Can organ-accumulated iron get shed again?

Can organ-accumulated iron get shed again?

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Hemochromatosis can lead to an accumulation of iron in some organs. If the accumulated amount is not too high, will it go down again upon correction of blood iron levels?

Can organ-accumulated iron get shed again? - Biology

Get to Know Our Ingredients

You know that old adage that says, “It’s what’s on the inside that counts”? It applies as much to lawn care as it does people, which is why we at Sunday work painstakingly to find the hardest-working, most punch-packing ingredients for every single product.

Scroll on to see what we’re made of.


Not only is nitrogen an essential element for all living things, but also it’s what your grass needs the most—and it’s the first number you’ll see in those fertilizer ratios. You may recall from biology class that 80% of the air around us is already nitrogen (if so, pat yourself on the back!). But it’s not so readily available in soil, and even then, plants can’t use it until it’s converted into nitrate or ammonium (1). That’s where we come in. By encouraging the production of chlorophyll, nitrogen promotes rapid growth and lush, green color—basically, two of the main things you want from your lawn. No nitrogen? No growth. Period.

Found in: Lawn nutrients

Phosphorus is another one of the Big Three nutrients, and the P in N-P-K. It’s present in smaller amounts in plant tissue, but it’s working hard behind the scenes helping out with rooting, seedling development, cell division, and the absorption of nutrients (1). But there’s more to the story. Due to overfertilization and runoff, many regions are experiencing eutrophication , which causes mineral buildup and algal blooms in bodies of water. To reduce any negative environmental impacts, Sunday nutrient pouches use an extremely targeted and limited dose of phosphorus for those customers that have a deficiency in their soil.

Found in: Lawn nutrients

Rounding out the macronutrients is potassium (its chemical symbol, K, comes from the neo-Latin kalium ). It plays a vital role in regulating several physiological processes, the most important of which is activating enzymes used in protein, sugar, and starch synthesis (i.e. converting food into energy!). It moves readily through soil and also helps maintain turgor pressure, which keeps plants from drooping. If your lawn is deficient in potassium, you may not notice obvious visual signs or color changes, but your lawn will be more susceptible to drought, winter injury, and disease (1). Bananas, anyone?

Found in: Lawn nutrients

Secondary & Micronutrients

Along with magnesium and sulfur, calcium is considered a secondary macronutrient in lawn fertilizers. It’s most beneficial on soil that is overly acidic (this is where your soil test comes in handy!), because neutralizing soil pH helps plants absorb the nutrients they need to grow (1). Calcium also acts as something of a shield—a barrier between a plant’s cells and potential pathogens such as bacteria and viruses. Pretty cool? We think so.

Found In: Lawn nutrients

Did you know that plants pump iron too? Well, kind of. An essential micronutrient, iron helps your grass develop a dark emerald green color in fact, a major symptom of iron-deficiency in your grass is chlorosis , or yellow mottling of the blades. But this is about more than just aesthetics. That darker green will help your grass warm up more quickly in the spring, thus kick-starting growth! Iron also plays a starring role in a variety of vital mechanisms including respiration, chlorophyll synthesis, and nitrogen metabolism (1).

Found in: Pet Patch, lawn nutrients

Soil Amendments

Let’s review some chemistry 101! Like all compounds, soil surfaces and liquid nutrients have a molecular charge. If those charges are not attracted to each other, the nutrients will simply runoff and be wasted. Enter surfactants. These “surface acting agents” reduce that surface tension by breaking down adhesive properties, thus improving a product’s ability to penetrate the soil and be absorbed more evenly (1). This is particularly helpful for improving patchy areas in your grass, and it can really improve moisture retention in soil that dries too quickly.

Found in: Heat Defense, Pet Patch

Derived from leonardite coal, humic acid is one of the most concentrated forms of organic material available to your soil. It’s often referred to as a “soil conditioner,” which means it can increase aeration, water-holding capacity, and nitrogen uptake. Better nutrient uptake makes for a more efficient fertilizer—and we’re all about that efficient, targeted approach!

Found in: Pet Patch, lawn nutrients


As a natural source of nitrogen used frequently in organic farming, soy protein is great for boosting lush grass growth and helping with plant stability over time. It provides a slow release of nutrients, which has a number of benefits: Lower risk of leaf burning, sustained grass growth, and less leaching (2). And, importantly, it results in similar plant growth and quality as synthetic fertilizers. Yay! But there is one big difference. Because soybeans sequester carbon dioxide during their growth cycle, they reduce the impact of warming on our climate (3). Also yay!

Found in: Lawn nutrients

It’s not just for sushi! This sustainably harvested plant is filled with powerhouse minerals and nutrients that help your grass grow lush and green (think nitrogen, potassium, magnesium, iron, zinc, and … well, the list goes on). What’s more, its low cellulose content allows it to break down quickly—meaning it gets to work on your soil right away. It’s rich in cytokinins, which are often called “stay green” hormones because of their ability to slow chlorophyll degradation and enhance root growth. Finally, seaweed is high in moisture, which helps your soil stay saturated for longer and reduces your need to water as often. Win-win!

Found in: Pet Patch, lawn nutrients

“Why am I feeding my lawn sugar?” We’re glad you asked! In addition to being a natural surfactant, molasses feeds the microbes in your soil to help build its fertility. It contains small amounts of key nutrients like manganese, magnesium, copper, and vitamin B-6. And the main reason it stands out? It’s an industrial byproduct, which means we can give a second life to something that would otherwise go to waste! Save your soil, and save the planet while you’re at it.

Found in: Lawn nutrients

Beet juice extract is another industrial byproduct that works hard for your lawn. It contains glycinebetaine, which helps plants cope with drought stress by stabilizing cell membranes. It’s non-toxic, environmentally safe, and water soluble. Finally, it’s been shown to increase the rate of photosynthesis in stressed plants (4)!

Found in: Lawn nutrients

Naturally Derived Pesticides

This powerful pesticide is botanically derived and highly effective against a variety of pests, including ants, mosquitoes, moths, flies, cockroaches, beetles, spiders, mites, and fleas. It’s biodegradable (great for the environment!), safe for people and pets when used properly, and comes from chrysanthemum flowers. But don’t let its cute origins fool you—it works on contact by attacking the insects’ nervous system. Overall, we love it because it helps reduce out-of-control pest populations while avoiding the residual effects of long-lasting pesticides.

A natural substance (“biopesticide”) produced by a soil bacterium, spinosad contains a neurotoxin that affects a variety of insects like fire ants, thrips, leafminers, mosquitos, fruit flies, and more (5). For colony control, it’s often formulated as mound drench or bait granules that ants carry back to the mound—working quickly and effectively on contact. Bonus? Many formulations are approved for organic gardening (6), and it’s non-toxic to pets. In fact, many pet soaps include spinosad to—you guessed it!—keep away bugs.

Found in: Ant Adios, Fire Ant Fighter

Wait, iron again? This hardworking element is a key component of our nutrient pouches and helps your lawn grow lush and green, but it’s deadly to weeds! Because iron doesn’t volatilize (a.k.a., evaporate) once it’s on the plant, iron-based herbicides are safer than many traditional products. Only broadleaf weeds (like dandelions and spurge) will absorb it in quantities high enough to cause necrosis—which looks like drying out then turning black within a few hours of application—so it’s safe to spray around your grass!

Found in: Dandelion Doom

The active ingredient in this fact-acting, powerful potion is “ammoniated soap of fatty acids.” In essence, it works to break down the leaf cuticle and destroy the integrity of the leaf cells, which leads to rapid leaf death. In fact, you may begin to see results in as little as 20 minutes (7)! It’s biodegradable and approved for organic gardening, and it won’t harm your trees (i.e., great for treating poison ivy vines). However, it is non-selective, which means it can damage your grass.

Found in: Weed Warrior

An essential oil derived from the wood of various conifers (typically in the pine or cypress families), cedar oil is an effective fungicide and insect repellent. It targets mosquitoes, ticks, and moths especially well, killing adult insects on contact by dissolving their exoskeletons. As an oil applied to open water, it also targets mosquitos, ticks, and fleas in the larval stage (8). Because of its low mammalian toxicity and low risk to the environment, the EPA considers it a minimum-risk pesticide.

Found in: Nix Ticks, Mosquito Deleto

In addition to its invigorating verbena scent, lemongrass oil is prized for its knockdown efficacy and repellency against mosquitos. It is a common ingredient in many global cuisines (in other words, non-toxic to humans!), but its active agent, citral, is a powerful insecticide that controls the adults of three different mosquito species: Aedes aegypti , Culex quinquefasciatus and Anopheles dirus (9).


Length and duration

The first menstrual period occurs after the onset of pubertal growth, and is called menarche. The average age of menarche is 12 to 15 years. [1] [7] However, it may occur as early as eight. [2] The average age of the first period is generally later in the developing world, and earlier in the developed world. [3] [8] The average age of menarche has changed little in the United States since the 1950s. [3]

Menstruation is the most visible phase of the menstrual cycle and its beginning is used as the marker between cycles. The first day of menstrual bleeding is the date used for the last menstrual period (LMP). The typical length of time between the first day of one period and the first day of the next is 21 to 45 days in young women, and 21 to 31 days in adults. [2] [3] The average length is 28 days one study estimated it at 29.3 days. [9] The variability of menstrual cycle lengths is highest for women under 25 years of age and is lowest, that is, most regular, for ages 25 to 39 years. [10] The variability increases slightly for women aged 40 to 44 years. [10]

Perimenopause is when a woman's fertility declines, and menstruation occurs less regularly in the years leading up to the final menstrual period, when a woman stops menstruating completely and is no longer fertile. The medical definition of menopause is one year without a period and typically occurs between 45 and 55 years in Western countries. [4] [11] Menopause before age 45 is considered premature in industrialized countries. [12] Like the age of menarche, the age of menopause is largely a result of cultural and biological factors. [ dubious – discuss ] [ failed verification ] Illnesses, certain surgeries, or medical treatments may cause menopause to occur earlier than it might have otherwise. [13]


The average volume of menstrual fluid during a monthly menstrual period is 35 millilitres (2.4 US tbsp) with 10–80 millilitres (0.68–5.41 US tbsp) considered typical. Menstrual fluid is the correct name for the flow, although many people prefer to refer to it as menstrual blood. Menstrual fluid is reddish-brown, a slightly darker color than venous blood. [11]

About half of menstrual fluid is blood. This blood contains sodium, calcium, phosphate, iron, and chloride, the extent of which depends on the woman. As well as blood, the fluid consists of cervical mucus, vaginal secretions, and endometrial tissue. Vaginal fluids in menses mainly contribute water, common electrolytes, organ moieties, and at least 14 proteins, including glycoproteins. [14]

Many women and girls notice blood clots during menstruation. These appear as clumps of blood that may look like tissue. If there was a miscarriage or a stillbirth, examination under a microscope can confirm if it was endometrial tissue or pregnancy tissue (products of conception) that was shed. [15] Sometimes menstrual clots or shed endometrial tissue is incorrectly thought to indicate an early-term miscarriage of an embryo. An enzyme called plasmin – contained in the endometrium – tends to inhibit the blood from clotting. [ medical citation needed ]

The amount of iron lost in menstrual fluid is relatively small for most women. [ better source needed ] [16] In one study, premenopausal women who exhibited symptoms of iron deficiency were given endoscopies. 86% of them actually had gastrointestinal disease and were at risk of being misdiagnosed simply because they were menstruating. [ non-primary source needed ] [17] Heavy menstrual bleeding, occurring monthly, can result in anemia. [18]

Hormonal changes

The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that make pregnancy possible. The ovarian cycle controls the production and release of eggs and the cyclic release of estrogen and progesterone. The uterine cycle governs the preparation and maintenance of the lining of the uterus (womb) to receive a fertilized egg. These cycles are concurrent and coordinated, normally last between 21 and 35 days in adult women, with a median length of 28 days, and continue for about 30–45 years.

Naturally occurring hormones drive the cycles the cyclical rise and fall of the follicle stimulating hormone prompts the production and growth of oocytes (immature egg cells). The hormone estrogen stimulates the uterus lining to thicken to accommodate an embryo should fertilization occur. The blood supply of the thickened lining (endometrium) provides nutrients to a successfully implanted embryo. If implantation does not occur, the lining breaks down and blood is released. Triggered by falling progesterone levels, menstruation (a "period", in common parlance) is the cyclical shedding of the lining, and is a sign that pregnancy has not occurred.

Who menstruates

In general, women may menstruate after they have started menarche and until the time of menopause. Women who do not menstruate include postmenopausal women, pregnant women, those experiencing amenorrhea, and trans women. [19] : 950 During pregnancy and for some time after childbirth, menstruation does not occur. The average length of postpartum amenorrhoea is longer when breastfeeding this is termed lactational amenorrhoea. [20] Trans men may or may not menstruate, depending on their individual circumstances. [21] : 1

Menstrual health overview

Although a normal and natural process, [22] some women experience problems sufficient to disrupt their lives as a result of their menstrual cycle. [23] These include acne, tender breasts, feeling tired, and premenstrual syndrome (PMS). [23] [24] More severe problems such as premenstrual dysphoric disorder are experienced by 3 to 8% of women. [25] [26] Dysmenorrhea or "period pain" [27] can cause cramps in the abdomen, back, or upper thighs that occur during the first few days of menstruation. [28] Debilitating period pain is not normal and can be a sign of something severe such as endometriosis. [29] These issues can significantly affect a woman's health and quality of life and timely interventions can improve the lives of these women. [30]

There are common culturally communicated misbeliefs that the menstrual cycle affects women's moods, causes depression or irritability, or that menstruation is a painful, shameful or unclean experience. Often a woman's normal mood variation is falsely attributed to the menstrual cycle. Much of the research is weak, but there appears to be a very small increase in mood fluctuations during the luteal and menstrual phases, and a corresponding decrease during the rest of the cycle. [31] Changing levels of estrogen and progesterone across the menstrual cycle exert systemic effects on aspects of physiology including the brain, metabolism, and musculoskeletal system. The result can be subtle physiological and observable changes to women's athletic performance including strength, aerobic, and anaerobic performance. [32] Changes to the brain have also been observed throughout the menstrual cycle [33] but do not translate into measurable changes in intellectual achievement – including academic performance, problem-solving, memory, and creativity. [34] Improvements in spatial reasoning ability during the menstruation phase of the cycle are probably caused by decreases in levels of estrogen and progesterone. [31]

Moods and premenstrual syndrome (PMS)

Premenstrual syndrome (PMS) refers to emotional and physical symptoms that regularly occur in the one to two weeks before the start of each menstrual period. [35] [36] Symptoms resolve around the start of bleeding. [35] Different women experience different symptoms. The common emotional symptoms include irritability and mood changes while the common physical symptoms include acne, tender breasts, bloating, and feeling tired these are also seen in women without PMS. [36] [35] Often symptoms are present for around six days. [37] An individual's pattern of symptoms may change over time. [37] Symptoms do not occur during pregnancy or following menopause. [35]

Diagnosis requires a consistent pattern of emotional and physical symptoms occurring after ovulation and before menstruation to a degree that interferes with normal life. [36] Emotional symptoms must not be present during the initial part of the menstrual cycle. [36] A daily list of symptoms over a few months may help in diagnosis. [37] Other disorders that cause similar symptoms need to be excluded before a diagnosis is made. [37]

The cause of PMS is unknown. [35] Some symptoms may be worsened by a high-salt diet, alcohol, or caffeine. [35] The underlying mechanism is believed to involve changes in hormone levels. [35] Reducing salt, caffeine, and stress along with increasing exercise is typically all that is recommended in those with mild symptoms. [35] Calcium and vitamin D supplementation may be useful in some. [37] Anti-inflammatory drugs such as naproxen may help with physical symptoms. [35] In those with more significant symptoms birth control pills or the diuretic spironolactone may be useful. [35] [37]

Up to 80% of women report having some symptoms prior to menstruation. [37] These symptoms qualify as PMS in 20 to 30% of pre-menopausal women. [37] Premenstrual dysphoric disorder (PMDD) is a more severe form of PMS that has greater psychological symptoms. [37] [35] PMDD affects three to eight percent of pre-menopausal women. [37] Antidepressant medication of the selective serotonin reuptake inhibitors class may be used for PMDD in addition to the usual measures for PMS. [35]


In most women, various physical changes are brought about by fluctuations in hormone levels during the menstrual cycle. This includes muscle contractions of the uterus (menstrual cramping) that can precede or accompany menstruation. Many women experience painful cramps, also known as dysmenorrhea, during menstruation. [38] Among adult women, that pain is severe enough to affect daily activity in only 2%–28%. [39] Severe symptoms that disrupt daily activities and functioning may be diagnosed as premenstrual dysphoric disorder. [40] These symptoms can be severe enough to affect a person's performance at work, school, and in every day activities in a small percentage of women. [5]

When severe pelvic pain and bleeding suddenly occur or worsen during a cycle, this could be due to ectopic pregnancy and spontaneous abortion. This is checked by using a pregnancy test, ideally as soon as unusual pain begins, because ectopic pregnancies can be life‑threatening. [41]

The most common treatment for menstrual cramps are non-steroidal anti-inflammatory drugs (NSAIDs). NSAIDs can be used to reduce moderate to severe pain, and all appear similar. [42] About 1 in 5 women do not respond to NSAIDs and require alternative therapy, such as simple analgesics or heat pads. [43] Other medications for pain management include aspirin or paracetamol and combined oral contraceptives. Although combined oral contraceptives may be used, there is insufficient evidence for the efficacy of intrauterine progestogens. [44]

One review found tentative evidence that acupuncture may be useful, at least in the short term. [45] Another review found insufficient evidence to determine an effect. [46]

Sexual activity and fertility

Sexual feelings and behaviors change during the menstrual cycle. Before and during ovulation, high levels of estrogen and androgens result in women having a relatively increased interest in sexual activity. [47] Unlike other mammals, women may show interest in sexual activity across all days of the menstrual cycle, regardless of fertility. [48]

Sexual intercourse during menstruation does not cause damage in itself, but the woman's body is more vulnerable during this time. Vaginal pH is higher and thus less acidic than normal, [49] the cervix is lower in its position, the cervical opening is more dilated, and the uterine endometrial lining is absent, thus allowing organisms direct access to the bloodstream through the numerous blood vessels that nourish the uterus. All these conditions increase the chance of infection during menstruation. [50]

Peak fertility (the time with the highest likelihood of pregnancy resulting from sexual intercourse) occurs during just a few days of the cycle: usually two days before and two days after the ovulation date. [51] This corresponds to the second and the beginning of the third week in a 28-day cycle. This fertile window varies from woman to woman, just as the ovulation date often varies from cycle to cycle for the same woman. [52] A variety of methods have been developed to help individual women estimate the relatively fertile and the relatively infertile days in the cycle these systems are called fertility awareness. [ medical citation needed ]

Interactions with other conditions

Known interactions between the menstrual cycle and certain health conditions include:

  • Some women with neurological conditions experience increased activity of their conditions at about the same time during each menstrual cycle. For example, drops in estrogen levels have been known to trigger migraines, [medical citation needed] especially when the woman who suffers migraines is also taking the birth control pill.
  • Many women with epilepsy have more seizures in a pattern linked to the menstrual cycle this is called "catamenial epilepsy". [53] Different patterns seem to exist (such as seizures coinciding with the time of menstruation, or coinciding with the time of ovulation), and the frequency with which they occur has not been firmly established.
  • Research indicates that women have a significantly higher likelihood of anterior cruciate ligament injuries in the pre-ovulatory stage, than post-ovulatory stage. [54]

Infrequent or irregular ovulation is called oligoovulation. [55] The absence of ovulation is called anovulation. Normal menstrual flow can occur without ovulation preceding it: an anovulatory cycle. In some cycles, follicular development may start but not be completed nevertheless, estrogens will be formed and stimulate the uterine lining. Anovulatory flow resulting from a very thick endometrium caused by prolonged, continued high estrogen levels is called estrogen breakthrough bleeding. Anovulatory bleeding triggered by a sudden drop in estrogen levels is called withdrawal bleeding. [56] Anovulatory cycles commonly occur before menopause (perimenopause) and in women with polycystic ovary syndrome. [57]

Very little flow (less than 10 ml) is called hypomenorrhea. Regular cycles with intervals of 21 days or fewer are polymenorrhea frequent but irregular menstruation is known as metrorrhagia. Sudden heavy flows or amounts greater than 80 ml are termed menorrhagia. [58] Heavy menstruation that occurs frequently and irregularly is menometrorrhagia. The term for cycles with intervals exceeding 35 days is oligomenorrhea. [59] Amenorrhea refers to more than three [58] to six [59] months without menses (while not being pregnant) during a woman's reproductive years. The term for painful periods is dysmenorrhea.

There is a wide spectrum of differences in how women experience menstruation. There are several ways that someone's menstrual cycle can differ from the norm:

Term Meaning
Oligomenorrhea Infrequent periods
Hypomenorrhea Short or light periods
Polymenorrhea Frequent periods (more frequently than every 21 days)
Hypermenorrhea Heavy or long periods (soaking a sanitary napkin or tampon every hour, menstruating longer than 7 days)
Dysmenorrhea Painful periods
Intermenstrual bleeding Breakthrough bleeding (also called spotting)
Amenorrhea Absent periods

Extreme psychological stress can also result in periods stopping. [60] More severe symptoms of anxiety or depression may be signs of premenstrual dysphoric disorder (PMDD) with is a depressive disorder. [61]

Dysfunctional uterine bleeding is a hormonally caused bleeding abnormality. Dysfunctional uterine bleeding typically occurs in premenopausal women who do not ovulate normally (i.e. are anovulatory). All these bleeding abnormalities need medical attention they may indicate hormone imbalances, uterine fibroids, or other problems. As pregnant women may bleed, a pregnancy test forms part of the evaluation of abnormal bleeding. [ medical citation needed ]

Women who had undergone female genital mutilation (particularly type III- infibulation) a practice common in parts of Africa, may experience menstrual problems, such as slow and painful menstruation, that is caused by the near-complete sealing off of the vagina. [62]


Dysmenorrhea, also known as painful periods or menstrual cramps, is pain during menstruation. [63] [64] Its usual onset occurs around the time that menstruation begins. [63] Symptoms typically last less than three days. [63] The pain is usually in the pelvis or lower abdomen. [63] Other symptoms may include back pain, diarrhea or nausea. [63]

Dysmenorrhea can occur without an underlying problem. [65] [66] Underlying issues that can cause dysmenorrhea include uterine fibroids, adenomyosis, and most commonly, endometriosis. [65] It is more common among those with heavy periods, irregular periods, those whose periods started before twelve years of age and those who have a low body weight. [63] A pelvic exam and ultrasound in individuals who are sexually active may be useful for diagnosis. [63] Conditions that should be ruled out include ectopic pregnancy, pelvic inflammatory disease, interstitial cystitis and chronic pelvic pain. [63]

Dysmenorrhea occurs less often in those who exercise regularly and those who have children early in life. [63] Treatment may include the use of a heating pad. [65] Medications that may help include NSAIDs such as ibuprofen, hormonal birth control and the IUD with progestogen. [63] [65] Taking vitamin B1 or magnesium may help. [64] Evidence for yoga, acupuncture and massage is insufficient. [63] Surgery may be useful if certain underlying problems are present. [64]

Estimates of the percentage of women of reproductive age affected vary from 20% to 90%. [63] [66] It is the most common menstrual disorder. [64] Typically, it starts within a year of the first menstrual period. [63] When there is no underlying cause, often the pain improves with age or following having a child. [64]

Menstrual products (also called "feminine hygiene" products) are made to absorb or catch menstrual blood. A number of different products are available - some are disposable, some are reusable. Where women can afford it, items used to absorb or catch menses are usually commercially manufactured products. Menstruating women manage menstruation primarily by wearing menstrual products such as tampons, napkins or menstrual cups to catch the menstrual blood.

The main disposable products (commercially manufactured) include:

    (also called sanitary towels or pads) – Rectangular pieces of material worn attached to the underwear to absorb menstrual flow, often with an adhesive backing to hold the pad in place. Disposable pads may contain wood pulp or gel products, usually with a plastic lining and bleached. – Disposable cylinders of treated rayon/cotton blends or all-cotton fleece, usually bleached, that are inserted into the vagina to absorb menstrual flow.

The main reusable products include:

    – A firm, flexible bell-shaped device worn inside the vagina to collect menstrual flow. – Pads that are made of cotton (often organic), terrycloth, or flannel, and may be handsewn (from material or reused old clothes and towels) or storebought.
  • Padded panties or period-proof underwear – Reusable cloth (usually cotton) underwear with extra absorbent layers sewn in to absorb flow. Some also use patented technology to be leak resistant, such as the brand THINX.

Due to poverty, some women cannot afford commercial feminine hygiene products. [67] [68] Instead, they use materials found in the environment or other improvised materials. [69] [70] “Period poverty” is a global issue affecting women and girls who do not have access to safe, hygienic sanitary products. [71] In addition, solid waste disposal systems in developing countries are often lacking, which means women have no proper place to dispose used products, such as pads. [72] Inappropriate disposal of used materials also creates pressures on sanitation systems as menstrual hygiene products can create blockages of toilets, pipes and sewers. [67]

Due to hormonal contraception

Menstruation can be delayed by the use of progesterone or progestins. For this purpose, oral administration of progesterone or progestin during cycle day 20 has been found to effectively delay menstruation for at least 20 days, with menstruation starting after 2–3 days have passed since discontinuing the regimen. [73]

Hormonal contraception affects the frequency, duration, severity, volume, and regularity of menstruation and menstrual symptoms. The most common form of hormonal contraception is the combined birth control pill, which contains both estrogen and progestogen. Although the primary function of the pill is to prevent pregnancy, it may be used to improve some menstrual symptoms and syndromes which affect menstruation, such as polycystic ovary syndrome (PCOS), endometriosis, adenomyosis, amenorrhea, menstrual cramps, menstrual migraines, menorrhagia (excessive menstrual bleeding), menstruation-related or fibroid-related anemia and dysmenorrhea (painful menstruation) by creating regularity in menstrual cycles and reducing overall menstrual flow. [74] [75]

Using the combined birth control pill, it is also possible for a woman to delay or completely eliminate menstrual periods, a practice called menstrual suppression. [76] Some women do this simply for convenience in the short-term, [77] while others prefer to eliminate periods altogether when possible. This can be done either by skipping the placebo pills, or using an extended cycle combined oral contraceptive pill, which were first marketed in the U.S. in the early 2000s. This continuous administration of active pills without the placebo can lead to the achievement of amenorrhea in 80% of users within 1 year of use. [78]

Due to breastfeeding

Breastfeeding causes negative feedback to occur on pulse secretion of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH). Depending on the strength of the negative feedback, breastfeeding women may experience complete suppression of follicular development, follicular development but no ovulation, or normal menstrual cycles may resume. [79] Suppression of ovulation is more likely when suckling occurs more frequently. [80] The production of prolactin in response to suckling is important to maintaining lactational amenorrhea. [81] On average, women who are fully breastfeeding whose infants suckle frequently experience a return of menstruation at fourteen and a half months postpartum. There is a wide range of response among individual breastfeeding women, however, with some experiencing return of menstruation at two months and others remaining amenorrheic for up to 42 months postpartum. [82]

Traditions, taboos and education

Many religions have menstruation-related traditions, for example: Islam prohibits sexual contact with women during menstruation in the 2nd chapter of the Quran. Some scholars argue that menstruating women are in a state in which they are unable to maintain wudhu, and are therefore prohibited from touching the Arabic version of the Qur'an. Other biological and involuntary functions such as vomiting, bleeding, sexual intercourse, and going to the bathroom also invalidate one's wudhu. [83] In Judaism, a woman during menstruation is called Niddah and may be banned from certain actions. For example, the Jewish Torah prohibits sexual intercourse with a menstruating woman. [84] In Hinduism, menstruating women are traditionally considered ritually impure and given rules to follow. [85] [86]

Menstruation education is frequently taught in combination with sex education at school in Western countries, although girls may prefer their mothers to be the primary source of information about menstruation and puberty. [87] Information about menstruation is often shared among friends and peers, which may promote a more positive outlook on puberty. [88] The quality of menstrual education in a society determines the accuracy of people's understanding of the process. [89] In many Western countries where menstruation is a taboo subject, girls tend to conceal the fact that they may be menstruating and struggle to ensure that they give no sign of menstruation. [89] Effective educational programs are essential to providing children and adolescents with clear and accurate information about menstruation. Schools can be an appropriate place for menstrual education to take place. [90] Programs led by peers or third-party agencies are another option. [90] Low-income girls are less likely to receive proper sex education on puberty, leading to a decreased understanding of why menstruation occurs and the associated physiological changes that take place. This has been shown to cause the development of a negative attitude towards menstruation. [91]

Seclusion during menstruation

In some cultures, women were isolated during menstruation due to menstrual taboos. [92] This is because they are seen as unclean, dangerous, or bringing bad luck to those who encounter them. These practices are common in parts of South Asia including India. [93] A 1983 report found women refraining from household chore during this period in India. [94] Chhaupadi is a social practice that occurs in the western part of Nepal for Hindu women, which prohibits a woman from participating in everyday activities during menstruation. Women are considered impure during this time, and are kept out of the house and have to live in a shed. Although chhaupadi was outlawed by the Supreme Court of Nepal in 2005, the tradition is slow to change. [95] [96] Women and girls in cultures which practice such seclusion are often confined to menstruation huts, which are places of isolation used by cultures with strong menstrual taboos. The practice has recently come under fire due to related fatalities. Nepal criminalized the practice in 2017 after deaths were reported after the elongated isolation periods, but “the practice of isolating menstruating women and girls continues.“ [97]

Beliefs around synchrony

Effects of the moon

Even though the average length of the human menstrual cycle is similar to that of the lunar cycle, in modern humans there is no relation between the two. [98] The relationship is believed to be a coincidence. [99] [100] Light exposure does not appear to affect the menstrual cycle in humans. [101] A meta-analysis of studies from 1996 showed no correlation between the human menstrual cycle and the lunar cycle, [102] nor did data analyzed by period-tracking app Clue, submitted by 1.5m women, of 7.5m menstrual cycles, however the lunar cycle and the average menstrual cycle were found to be basically equal in length. [103]


Beginning in 1971, some research suggested that menstrual cycles of cohabiting women became synchronized (menstrual synchrony). [104] Subsequent research has called this hypothesis into question. [105] A 2013 review concluded that menstrual synchrony likely does not exist. [106]

Some countries, mainly in Asia, have menstrual leave to provide women with either paid or unpaid leave of absence from their employment while they are menstruating. [107] Countries with policies include Japan, Taiwan, Indonesia, and South Korea. [108] [109] The practice is controversial due to concerns that it bolsters the perception of women as weak, inefficient workers, [107] as well as concerns that it is unfair to men, [110] [111] and that it furthers gender stereotypes and the medicalization of menstruation. [108]


Menstrual Hygiene Day is an annual awareness day on May 28 to highlight the importance of good menstrual hygiene management at a global level.

At 16-years-old, Nadya Okamoto founded the organization, PERIOD, and wrote the book Period Power: a Manifesto for the Menstrual Movement. [112]

The word "menstruation" is etymologically related to "moon". The terms "menstruation" and "menses" are derived from the Latin mensis (month), which in turn relates to the Greek mene (moon) and to the roots of the English words month and moon. [113]

Some organizations have begun to use the term "menstruator" instead of "menstruating women", a term that has been in use since at least 2010. [19] : 950 The term menstruator is used by some activists and scholars in order to “express solidarity with women who do not menstruate, transgender men who do, and intersexual and genderqueer individuals”. [19] : 950 However, referring to people who menstruate as "menstruators" has also been criticized by some feminists who consider sex differences important and the term woman to be necessary to resist patriarchy. [19] : 950

Most female mammals have an estrous cycle, but not all have a menstrual cycle that results in menstruation. Menstruation in mammals occurs in some close evolutionary relatives such as chimpanzees. [114]

  1. ^ ab
  2. Women's Gynecologic Health. Jones & Bartlett Publishers. 2011. p. 94. ISBN9780763756376 . Archived from the original on 26 June 2015.
  3. ^ abcdefg
  4. "Menstruation and the menstrual cycle fact sheet". Office of Women's Health. 23 December 2014. Archived from the original on 26 June 2015 . Retrieved 25 June 2015 .
  5. ^ abcde
  6. Diaz A, Laufer MR, Breech LL, American Academy of Pediatrics Committee on Adolescence, American College of Obstetricians and Gynecologists Committee on Adolescent Health (November 2006). "Menstruation in girls and adolescents: using the menstrual cycle as a vital sign". Pediatrics. 118 (5): 2245–50. doi: 10.1542/peds.2006-2481 . PMID17079600.
  7. ^ ab
  8. "Menopause: Overview". 28 June 2013. Archived from the original on 2 April 2015 . Retrieved 8 March 2015 .
  9. ^ ab
  10. Biggs WS, Demuth RH (October 2011). "Premenstrual syndrome and premenstrual dysphoric disorder". American Family Physician. 84 (8): 918–24. PMID22010771.
  11. ^
  12. "Premenstrual syndrome (PMS) fact sheet". Office on Women's Health. 23 December 2014. Archived from the original on 28 June 2015 . Retrieved 23 June 2015 .
  13. ^
  14. Karapanou O, Papadimitriou A (September 2010). "Determinants of menarche". Reproductive Biology and Endocrinology. 8: 115. doi:10.1186/1477-7827-8-115. PMC2958977 . PMID20920296.
  15. ^
  16. Alvergne A, Högqvist Tabor V (June 2018). "Is Female Health Cyclical? Evolutionary Perspectives on Menstruation". Trends in Ecology & Evolution. 33 (6): 399–414. arXiv: 1704.08590 . doi:10.1016/j.tree.2018.03.006. PMID29778270. S2CID4581833.
  17. ^
  18. Bull, Jonathan R. Rowland, Simon P. Scherwitzl, Elina Berglund Scherwitzl, Raoul Danielsson, Kristina Gemzell Harper, Joyce (27 August 2019). "Real-world menstrual cycle characteristics of more than 600,000 menstrual cycles". NPJ Digital Medicine. 2 (1): 83. doi:10.1038/s41746-019-0152-7. ISSN2398-6352. PMC6710244 . PMID31482137.
  19. ^ ab
  20. Chiazze L, Brayer FT, Macisco JJ, Parker MP, Duffy BJ (February 1968). "The length and variability of the human menstrual cycle". JAMA. 203 (6): 377–80. doi:10.1001/jama.1968.03140060001001. PMID5694118.
  21. ^ abCarlson, Eisenstat & Ziporyn 2004, p. 381.
  22. ^
  23. "Clinical topic — Menopause". NHS. Archived from the original on 7 July 2009 . Retrieved 2 November 2009 .
  24. ^
  25. Mishra GD, Chung HF, Cano A, Chedraui P, Goulis DG, Lopes P, Mueck A, Rees M, Senturk LM, Simoncini T, Stevenson JC, Stute P, Tuomikoski P, Lambrinoudaki I (May 2019). "EMAS position statement: Predictors of premature and early natural menopause". Maturitas. 123: 82–88. doi:10.1016/j.maturitas.2019.03.008. hdl: 10138/318039 . PMID31027683.
  26. ^
  27. Farage M (22 March 2013). The Vulva: Anatomy, Physiology, and Pathology. CRC Press. pp. 155–158.
  28. ^
  29. "Menstrual blood problems: Clots, color and thickness". WebMD. Archived from the original on 23 September 2011 . Retrieved 20 September 2011 .
  30. ^
  31. Clancy, Kate (27 July 2011). "Iron-deficiency is not something you get just for being a lady". SciAm. Archived from the original on 17 March 2012.
  32. ^
  33. Kepczyk T, Cremins JE, Long BD, Bachinski MB, Smith LR, McNally PR (January 1999). "A prospective, multidisciplinary evaluation of premenopausal women with iron-deficiency anemia". The American Journal of Gastroenterology. 94 (1): 109–15. PMID9934740.
  34. ^
  35. Mansour D, Hofmann A, Gemzell-Danielsson K (January 2021). "A Review of Clinical Guidelines on the Management of Iron Deficiency and Iron-Deficiency Anemia in Women with Heavy Menstrual Bleeding". Advances in Therapy. 38 (1): 201–225. doi:10.1007/s12325-020-01564-y. PMC7695235 . PMID33247314.
  36. ^ abcd
  37. Rydström, Klara (2020), Bobel, Chris Winkler, Inga T. Fahs, Breanne Hasson, Katie Ann (eds.), "Chapter 68: Degendering Menstruation: Making Trans Menstruators Matter", The Palgrave Handbook of Critical Menstruation Studies, Singapore: Springer Singapore, pp. 945–959, doi: 10.1007/978-981-15-0614-7_68 , ISBN978-981-15-0613-0 , PMID33347169 , retrieved 23 March 2021
  38. ^
  39. McNeilly AS, Tay CC, Glasier A (February 1994). "Physiological mechanisms underlying lactational amenorrhea". Annals of the New York Academy of Sciences. 709 (1): 145–55. Bibcode:1994NYASA.709..145M. doi:10.1111/j.1749-6632.1994.tb30394.x. PMID8154698. S2CID11608165.
  40. ^
  41. Frank, S. E. Dellaria, Jac (2020), Bobel, Chris Winkler, Inga T. Fahs, Breanne Hasson, Katie Ann (eds.), "Navigating the Binary: A Visual Narrative of Trans and Genderqueer Menstruation", The Palgrave Handbook of Critical Menstruation Studies, Singapore: Springer Singapore, pp. 69–76, doi: 10.1007/978-981-15-0614-7_7 , ISBN978-981-15-0613-0 , PMID33347161 , retrieved 10 May 2021
  42. ^Prior 2020, p. 50. sfn error: no target: CITEREFPrior2020 (help)
  43. ^ ab
  44. Gudipally PR, Sharma GK (2020). "Premenstrual syndrome". StatPearls [Internet] (Review). PMID32809533.
  45. ^
  46. Ferries-Rowe E, Corey E, Archer JS (November 2020). "Primary Dysmenorrhea: Diagnosis and Therapy". Obstetrics and Gynecology. 136 (5): 1047–1058. doi:10.1097/AOG.0000000000004096. PMID33030880.
  47. ^
  48. Reed BF, Carr BR, Feingold KR, et al. (2018). The Normal Menstrual Cycle and the Control of Ovulation. Endotext (Review). PMID25905282. Archived from the original on 28 May 2021 . Retrieved 8 January 2021 .
  49. ^
  50. Appleton SM (March 2018). "Premenstrual syndrome: evidence-based evaluation and treatment". Clinical Obstetrics and Gynecology (Review). 61 (1): 52–61. doi:10.1097/GRF.0000000000000339. PMID29298169. S2CID28184066.
  51. ^
  52. Nagy H, Khan MA (2020). "Dysmenorrhea". StatPearls (Review). PMID32809669.
  53. ^
  54. Baker FC, Lee KA (September 2018). "Menstrual cycle effects on sleep". Sleep Medicine Clinics (Review). 13 (3): 283–94. doi:10.1016/j.jsmc.2018.04.002. PMID30098748.
  55. ^
  56. Maddern J, Grundy L, Castro J, Brierley SM (2020). "Pain in endometriosis". Frontiers in Cellular Neuroscience. 14: 590823. doi:10.3389/fncel.2020.590823. PMC7573391 . PMID33132854.
  57. ^
  58. Matteson KA, Zaluski KM (September 2019). "Menstrual health as a part of preventive health care". Obstetrics and Gynecology Clinics of North America (Review). 46 (3): 441–53. doi:10.1016/j.ogc.2019.04.004. PMID31378287.
  59. ^ abElse-Quest & Hyde 2021, pp. 258–61. sfn error: no target: CITEREFElse-QuestHyde2021 (help)
  60. ^
  61. Carmichael MA, Thomson RL, Moran LJ, Wycherley TP (February 2021). "The impact of menstrual cycle phase on athletes' performance: a narrative review". Int J Environ Res Public Health (Review). 18 (4). doi:10.3390/ijerph18041667. PMC7916245 . PMID33572406.
  62. ^
  63. Pletzer B, Harris TA, Scheuringer A, Hidalgo-Lopez E (October 2019). "The cycling brain: menstrual cycle related fluctuations in hippocampal and fronto-striatal activation and connectivity during cognitive tasks". Neuropsychopharmacology. 44 (11): 1867–75. doi:10.1038/s41386-019-0435-3. PMC6785086 . PMID31195407.
  64. ^
  65. Le J, Thomas N, Gurvich C (March 2020). "Cognition, the menstrual cycle, and premenstrual disorders: a review". Brain Sci (Review). 10 (4). doi:10.3390/brainsci10040198. PMC7226433 . PMID32230889.
  66. ^ abcdefghijkl
  67. "Premenstrual syndrome (PMS) fact sheet". Office on Women's Health. 23 December 2014. Archived from the original on 28 June 2015 . Retrieved 23 June 2015 .
  68. ^ abcd
  69. Dickerson, Lori M. Mazyck, Pamela J. Hunter, Melissa H. (2003). "Premenstrual Syndrome". American Family Physician. 67 (8): 1743–52. PMID12725453. Archived from the original on 13 May 2008.
  70. ^ abcdefghij
  71. Biggs, WS Demuth, RH (15 October 2011). "Premenstrual syndrome and premenstrual dysphoric disorder". American Family Physician. 84 (8): 918–24. PMID22010771.
  72. ^
  73. Ju H, Jones M, Mishra G (1 January 2014). "The prevalence and risk factors of dysmenorrhea". Epidemiologic Reviews. 36 (1): 104–13. doi: 10.1093/epirev/mxt009 . PMID24284871.
  74. ^
  75. Ju H, Jones M, Mishra G (1 January 2014). "The prevalence and risk factors of dysmenorrhea". Epidemiologic Reviews. 36 (1): 104–13. doi: 10.1093/epirev/mxt009 . PMID24284871.
  76. ^
  77. "Premenstrual syndrome (PMS)". 12 July 2017 . Retrieved 3 January 2020 .
  78. ^
  79. "Ectopic Pregnancy Clinical Presentation: History, Physical Examination". Archived from the original on 29 March 2013.
  80. ^
  81. Latthe, PM Champaneria, R Hellman, Kevin M. (21 October 2014). "Dysmenorrhoea". BMJ Clinical Evidence. 2014: 390–400. doi:10.1016/j.ajog.2017.08.108. PMC4205951 . PMID25338194.
  82. ^
  83. Oladosu, Folabomi A. Tu, Frank F. Hellman, Kevin M. (April 2018). "Nonsteroidal antiinflammatory drug resistance in dysmenorrhea: epidemiology, causes, and treatment". American Journal of Obstetrics and Gynecology. 218 (4): 390–400. doi:10.1016/j.ajog.2017.08.108. PMC5839921 . PMID28888592.
  84. ^
  85. Latthe, PM Champaneria, R (21 October 2014). "Dysmenorrhoea". BMJ Clinical Evidence. 2014: 390–400. doi:10.1016/j.ajog.2017.08.108. PMC4205951 . PMID25338194.
  86. ^
  87. Woo, Hye Lin Ji, Hae Ri Pak, Yeon Kyoung Lee, Hojung Heo, Su Jeong Lee, Jin Moo Park, Kyoung Sun (June 2018). "The efficacy and safety of acupuncture in women with primary dysmenorrhea". Medicine. 97 (23): e11007. doi:10.1097/MD.0000000000011007. PMC5999465 . PMID29879061.
  88. ^
  89. Smith, Caroline A Armour, Mike Zhu, Xiaoshu Li, Xun Lu, Zhi Yong Song, Jing (18 April 2016). "Acupuncture for dysmenorrhoea". Cochrane Database of Systematic Reviews. 4: CD007854. doi:10.1002/14651858.CD007854.pub3. PMID27087494.
  90. ^
  91. Levay S, Baldwin J, Baldwin J (2015). "Women's Bodies". Discovering Human Sexuality. Massachusetts: Sinauer Associtates, Inc. p. 44. ISBN9781605352756 .
  92. ^
  93. Thornhill R, Gangestad SW (2008). "Background and Overview of the Book". The Evolutionary Biology of Human Female Sexuality. New York: Oxford University Press. p. 12. ISBN9780195340990 .
  94. ^
  95. Wagner G, Ottesen B (June 1982). "Vaginal physiology during menstruation". Annals of Internal Medicine. 96 (6 Pt 2): 921–3. doi:10.7326/0003-4819-96-6-921. PMID6807162.
  96. ^
  97. Oettel M, Schillinger E (6 December 2012). Estrogens and Antiestrogens II: Pharmacology and Clinical Application of Estrogens and Antiestrogen. Springer Science & Business Media. p. 355. ISBN9783642601071 . Archived from the original on 16 January 2017.
  98. ^
  99. "Archived copy". Archived from the original on 21 December 2008 . Retrieved 22 September 2008 . CS1 maint: archived copy as title (link)
  100. ^
  101. Creinin, Mitchell D. Keverline, Sharon Meyn, Leslie A. (2004). "How regular is regular? An analysis of menstrual cycle regularity". Contraception. 70 (4): 289–92. doi:10.1016/j.contraception.2004.04.012. PMID15451332.
  102. ^
  103. Herzog AG (March 2008). "Catamenial epilepsy: definition, prevalence pathophysiology and treatment". Seizure. 17 (2): 151–9. doi:10.1016/j.seizure.2007.11.014. PMID18164632. S2CID6903651.
  104. ^
  105. Renstrom P, Ljungqvist A, Arendt E, et al. (June 2008). "Non-contact ACL injuries in female athletes: an International Olympic Committee current concepts statement". British Journal of Sports Medicine. 42 (6): 394–412. doi:10.1136/bjsm.2008.048934. PMC3920910 . PMID18539658.
  106. ^
  107. Galan N (16 April 2008). "Oligoovulation". . Retrieved 12 October 2008 .
  108. ^
  109. Weschler T (2002). Taking Charge of Your Fertility (Revised ed.). New York: HarperCollins. pp. 107. ISBN978-0-06-093764-5 .
  110. ^Anovulation at eMedicine
  111. ^ abMenstruation Disorders at eMedicine
  112. ^ ab
  113. Oriel KA, Schrager S (October 1999). "Abnormal uterine bleeding". American Family Physician. 60 (5): 1371–80, discussion 1381-2. PMID10524483.
  114. ^
  115. Meczekalski B, Katulski K, Czyzyk A, Podfigurna-Stopa A, Maciejewska-Jeske M (November 2014). "Functional hypothalamic amenorrhea and its influence on women's health". Journal of Endocrinological Investigation. 37 (11): 1049–56. doi:10.1007/s40618-014-0169-3. PMC4207953 . PMID25201001.
  116. ^
  117. Mishra, Sanskriti Marwaha, Raman (2019). "Premenstrual Dysphoric Disorder". StatPearls. StatPearls Publishing. PMID30335340 . Retrieved 5 August 2019 .
  118. ^
  119. "Health risks of female genital mutilation (FGM)". World Health Organization. Archived from the original on 29 November 2014.
  120. ^ abcdefghijklm
  121. Osayande AS, Mehulic S (March 2014). "Diagnosis and initial management of dysmenorrhea". American Family Physician. 89 (5): 341–6. PMID24695505.
  122. ^ abcde
  123. American College of Obstetricians and Gynecologists (January 2015). "FAQ046 Dynsmenorrhea: Painful Periods" (PDF) . Archived (PDF) from the original on 27 June 2015 . Retrieved 26 June 2015 .
  124. ^ abcd
  125. "Menstruation and the menstrual cycle fact sheet". Office of Women's Health. 23 December 2014. Archived from the original on 26 June 2015 . Retrieved 25 June 2015 .
  126. ^ ab
  127. "Dysmenorrhea and Endometriosis in the Adolescent". ACOG. American College of Obstetricians and Gynecologists. 20 November 2018 . Retrieved 21 November 2018 .
  128. ^ ab
  129. Kaur, Rajanbir Kaur, Kanwaljit Kaur, Rajinder (2018). "Menstrual Hygiene, Management, and Waste Disposal: Practices and Challenges Faced by Girls/Women of Developing Countries". Journal of Environmental and Public Health. 2018: 1730964. doi:10.1155/2018/1730964. ISSN1687-9805. PMC5838436 . PMID29675047.
  130. ^
  131. "UK girls 'too poor to afford tampons ' ". 14 March 2017 . Retrieved 27 April 2019 .
  132. ^ Chin, L. (2014) Period of shame - The Effects of Menstrual Hygiene Management on Rural Women and Girls' Quality of Life in Savannakhet, Laos [Master's thesis] LUMID International Master programme in applied International Development and Management [accessed 10 August 2015]
  133. ^ House, S., Mahon, T., Cavill, S. (2012). Menstrual hygiene matters - A resource for improving menstrual hygiene around the worldArchived 24 September 2015 at the Wayback Machine. WaterAid, UK
  134. ^
  135. "Period poverty". ActionAid UK.
  136. ^ Kjellén, M., Pensulo, C., Nordqvist, P., Fogde, M. (2012). Global review of sanitation systems trends and interactions with menstrual management practices - Report for the menstrual management and sanitation systems project. Stockholm Environment Institute (SEI), Stockholm, Sweden
  137. ^
  138. Goldstuck N (2011). "Progestin potency – Assessment and relevance to choice of oral contraceptives". Middle East Fertility Society Journal. 16 (4): 248–253. doi: 10.1016/j.mefs.2011.08.006 . ISSN1110-5690.
  139. ^
  140. CYWH Staff (18 October 2011). "Medical Uses of the Birth Control Pill" . Retrieved 1 February 2013 .
  141. ^
  142. Curtis, Kathryn M. Tepper, Naomi K. Jatlaoui, Tara C. Berry-Bibee, Erin Horton, Leah G. Zapata, Lauren B. Simmons, Katharine B. Pagano, H. Pamela Jamieson, Denise J. (2016). "U.S. Medical Eligibility Criteria for Contraceptive Use, 2016". MMWR. Recommendations and Reports. 65 (3): 1–103. doi: 10.15585/mmwr.rr6503a1 . ISSN1057-5987. PMID27467196.
  143. ^
  144. "Delaying your period with birth control pills". Mayo Clinic. Archived from the original on 26 September 2011 . Retrieved 20 September 2011 .
  145. ^
  146. "How can I delay my period while on holiday?". National Health Service, United Kingdom. Archived from the original on 5 August 2011 . Retrieved 20 September 2011 .
  147. ^
  148. Rome, Ellen S. Strandjord, Sarah E. (22 September 2015). "Monthly Periods—Are They Necessary?". Pediatric Annals. 44 (9): e231–e236. doi:10.3928/00904481-20150910-11. ISSN0090-4481. PMID26431242.
  149. ^
  150. McNeilly AS (2001). "Lactational control of reproduction". Reproduction, Fertility, and Development. 13 (7–8): 583–90. doi:10.1071/RD01056. PMID11999309.
  151. ^
  152. Kippley J, Kippley S (1996). The Art of Natural Family Planning (4th ed.). Cincinnati, OH: The Couple to Couple League. p. 347. ISBN0-926412-13-2 .
  153. ^
  154. Stallings JF, Worthman CM, Panter-Brick C, Coates RJ (February 1996). "Prolactin response to suckling and maintenance of postpartum amenorrhea among intensively breastfeeding Nepali women". Endocrine Research. 22 (1): 1–28. doi:10.3109/07435809609030495. PMID8690004.
  155. ^
  156. "Breastfeeding: Does It Really Space Babies?". The Couple to Couple League International. Internet Archive. 17 January 2008. Archived from the original on 17 January 2008 . Retrieved 21 September 2008 . , which cites:
  157. Kippley SK, Kippley JF (November–December 1972). "The relation between breastfeeding and amenorrhea: report of a survey". Jogn Nursing. 1 (4): 15–21. doi:10.1111/j.1552-6909.1972.tb00558.x. PMID4485271.
  158. Kippley SK (November–December 1986). "Breastfeeding survey results similar to 1971 study". The CCL News. 13 (3): 10.
  159. Kippley SK (January–February 1987). "Breastfeeding survey results similar to 1971 study". The CCL News. 13 (4): 5.
  160. ^
  161. "Sahih Bukhari, Chapter: 6, Menstrual Periods".
  162. ^ Leviticus 15:19-30, 18:19, 20:18
  163. ^
  164. Dunnavant, Nicki (2012). "Restriction and Renewal, Pollution and Power, Constraint and Community: The Paradoxes of Religious Women's Experiences of Menstruation". Sex Roles.
  165. ^
  166. Garg, Suneela Anand, Tanu (2015). "Menstruation related myths in India: strategies for combating it". Journal of Family Medicine and Primary Care. 4 (2): 184–186. doi:10.4103/2249-4863.154627. ISSN2249-4863. PMC4408698 . PMID25949964.
  167. ^
  168. Sooki Z, Shariati M, Chaman R, Khosravi A, Effatpanah M, Keramat A (March 2016). "The Role of Mother in Informing Girls About Puberty: A Meta-Analysis Study". Nursing and Midwifery Studies. 5 (1): e30360. doi:10.17795/nmsjournal30360. PMC4915208 . PMID27331056.
  169. ^
  170. Hatami M, Kazemi A, Mehrabi T (30 December 2015). "Effect of peer education in school on sexual health knowledge and attitude in girl adolescents". Journal of Education and Health Promotion. 4: 78. doi:10.4103/2277-9531.171791 (inactive 31 May 2021). PMC4944604 . PMID27462620. CS1 maint: DOI inactive as of May 2021 (link)
  171. ^ ab
  172. Allen KR, Kaestle CE, Goldberg AE (February 2011). "More than just a punctuation mark: How boys and young men learn about menstruation". Journal of Family Issues. 32 (2): 129–56. doi:10.1177/0192513x10371609. S2CID145531604.
  173. ^ ab
  174. Kirby D (February 2002). "The impact of schools and school programs upon adolescent sexual behavior". Journal of Sex Research. 39 (1): 27–33. doi:10.1080/00224490209552116. PMID12476253. S2CID45063072.
  175. ^
  176. Herbert, Ann C. Ramirez, Ana Maria Lee, Grace North, Savannah J. Askari, Melanie S. West, Rebecca L. Sommer, Marni (April 2017). "Puberty Experiences of Low-Income Girls in the United States: A Systematic Review of Qualitative Literature From 2000 to 2014". The Journal of Adolescent Health. 60 (4): 363–379. doi:10.1016/j.jadohealth.2016.10.008. ISSN1879-1972. PMID28041680.
  177. ^
  178. Gottlieb A (2020). "Chapter 14: Menstrual Taboos: Moving Beyond the Curse". In Bobel C, Winkler IG, Fahs B, Hasson KA, Kissling EA, Roberts T (eds.). The Palgrave Handbook of Critical Menstruation Studies. Palgrave Macmillan. doi:10.1007/978-981-15-0614-7_14. ISBN978-981-15-0614-7 . PMID33347165.
  179. ^
  180. Arthur Kleinman Byron J. Good Byron Good (1985). Culture and Depression: Studies in the Anthropology and Cross-Cultural Psychiatry of Affect and Disorder. University of California Press. pp. 203–204. ISBN978-0-520-05883-5 .
  181. ^
  182. Janice Delaney Mary Jane Lupton Emily Toth (1988). The Curse: A Cultural History of Menstruation. University of Illinois Press. p. 14. ISBN978-0-252-01452-9 .
  183. ^
  184. "Nepal: Emerging from menstrual quarantine". United Nations High Commissioner for Refugees (UNHCR). August 2011.
  185. ^
  186. Sharma S (15 September 2005). "Women hail menstruation ruling". BBC News.
  187. ^
  188. Canning M (September 2019). "Menstrual Health and the Problem with Menstrual Stigma". The Federation of American Women's Clubs Overseas, Inc. (FAWCO).
  189. ^
  190. Vertebrate Endocrinology (5 ed.). Academic Press. 2013. p. 361. ISBN9780123964656 .
  191. ^
  192. Gutsch WA (1997). 1001 things everyone should know about the universe (1st ed.). New York: Doubleday. p. 57. ISBN9780385482233 .
  193. ^
  194. Barash DP, Lipton JE (2009). "Synchrony and Its Discontents". How women got their curves and other just-so stories evolutionary enigmas ([Online-Ausg.]. ed.). New York: Columbia University Press. ISBN9780231518390 .
  195. ^
  196. Kristin H. Lopez (2013). Human Reproductive Biology. Academic Press. p. 53. ISBN9780123821850 . Archived from the original on 21 June 2015.
  197. ^ As cited by Adams, Cecil, "What's the link between the moon and menstruation?" (accessed 6 June 2006):
  198. Abell GO, Singer B (1983). Science and the Paranormal: Probing the Existence of the Supernatural. Scribner Book Company. ISBN978-0-684-17820-2 .
  199. ^
  200. "The myth of moon phases and menstruation". Clue. 3 December 2018 . Retrieved 3 December 2018 .
  201. ^
  202. Stern K, McClintock MK (March 1998). "Regulation of ovulation by human pheromones". Nature. 392 (6672): 177–9. Bibcode:1998Natur.392..177S. doi:10.1038/32408. PMID9515961. S2CID4426700.
  203. ^
  204. Adams C (20 December 2002). "Does menstrual synchrony really exist?". The Straight Dope. The Chicago Reader . Retrieved 10 January 2007 .
  205. ^
  206. Harris AL, Vitzthum VJ (2013). "Darwin's legacy: an evolutionary view of women's reproductive and sexual functioning". Journal of Sex Research. 50 (3–4): 207–46. doi:10.1080/00224499.2012.763085. PMID23480070. S2CID30229421.
  207. ^ ab
  208. Matchar E (16 May 2014). "Should Paid 'Menstrual Leave' Be a Thing?" . Retrieved 21 June 2015 .
  209. ^ ab
  210. Levitt RA, Barnack-Tavlaris JL (2020). "Chapter 43: Addressing Menstruation in the Workplace: The Menstrual Leave Debate". In Bobel C, Winkler IG, Fahs B, Hasson KA, Kissling EA, Roberts T (eds.). The Palgrave Handbook of Critical Menstruation Studies. Palgrave Macmillan. doi:10.1007/978-981-15-0614-7_43. ISBN978-981-15-0614-7 . PMID33347190.
  211. ^ King S. (2021) Menstrual Leave: Good Intention, Poor Solution. In: Hassard J., Torres L.D. (eds) Aligning Perspectives in Gender Mainstreaming. Aligning Perspectives on Health, Safety and Well-Being. Springer, Cham. doi:10.1007/978-3-030-53269-7_9
  212. ^
  213. Price C (11 October 2006). "Should women get paid menstruation leave?". Salon . Retrieved 16 March 2016 .
  214. ^
  215. "Menstrual Leave: Delightful or Discriminatory?". Lip Magazine. 4 August 2013 . Retrieved 16 March 2016 .
  216. ^
  217. Petersen, Lilli. "Period Activist Nadya Okamoto Is Turning Adversity Into Purpose During Quarantine". Elite Daily . Retrieved 22 October 2020 .
  218. ^
  219. Allen K (2007). The Reluctant Hypothesis: A History of Discourse Surrounding the Lunar Phase Method of Regulating Conception. Lacuna Press. p. 239. ISBN978-0-9510974-2-7 .
  220. ^
  221. Strassmann BI (June 1996). "The evolution of endometrial cycles and menstruation". The Quarterly Review of Biology. 71 (2): 181–220. doi:10.1086/419369. PMID8693059.

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Can organ-accumulated iron get shed again? - Biology

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Experiment sheds new light on prehistoric ocean conditions

Graduated cylinder model of the ocean. The green shows cyanobacteria and the brown shows the oxidized iron. Credit: Iowa State University's College of Liberal Arts and Sciences

A new experiment by Iowa State University's Elizabeth Swanner that evaluates the reduction of iron in prehistoric oceans may reinterpret the conditions under which iron-rich sedimentary rock is formed.

Swanner, an assistant professor of geological and atmospheric sciences, was part of an international research team including researchers from the University of Tuebingen in Germany and the Chinese Academy of Sciences in Beijing. The team modeled the prehistoric ocean, similar to that of the Archean Era 2.5 billion years ago within a graduated cylinder.

"We really only wanted to simulate it in the vertical dimension, so we used a graduated cylinder and modified it," Swanner said.

In a previous experiment, the researchers had modified the cylinder to simulate an Archean ocean with large amounts of iron and no oxygen except for what was made by cyanobacteria. Ports along the cylinder's side allowed for sampling at various levels.

"We were studying cyanobacteria because these are the organisms which we think put all of the oxygen in the atmosphere originally," she said.

The research, recently published by Scientific Reports, showed that despite the oxygenation by the cyanobacteria, much of the iron did not remain oxidized but was reduced again into its dissolved form.

This unexpected result may be explained by an enzyme on cyanobacteria which reduces iron. In the modern ocean, which contains at least 1,000 times less iron, cyanobacteria reduce a small amount of iron, but the experiment showed a larger amount of iron reduction than the researchers anticipated. Another possible explanation is that the iron is reduced by a photochemical reaction occurring when the iron is hit by light.

The implications of this finding could change the conditions under which iron-rich sedimentary rocks are thought to be formed from the ancient oceans.

"Traditionally if you see iron enriched in sediments from the ocean you tend to think it was deposited under anoxic conditions," Swanner said. "But potentially we have a way to still deposit a lot of iron but have it be deposited under fully oxygenated conditions."

The initial results in the laboratory prompt new questions for Swanner, including whether she will find evidence of this process in the Midwestern lakes that her research group is now studying. These lakes have iron at the bottom and oxygen only in the top of the water column, and also contain cyanobacteria.

Did You Know Your Hair Follicle Is Considered an Organ?

We’re obviously hair obsessed, but the little we know about what’s actually going on with our manes (read, what it’s made of, and how or why it grows) is kinda cray. To find out the true biology of hair, we reached out to Dr. Dominic Burg, Chief Scientist for évolis Professional and he gave us an entire course worth of information. Break out the caffeine and prepare for Hair Bio 101.

Why Hair Grows

“The hair on your head is actually a dead fiber,” explains Dr. Burg. What makes it grow is the action of small organs known as hair follicles, and these follicles control hair growth over repeating hair cycles. “Hair follicles are actually true organs, much like any other organ in your body and like other organs, are made up of different parts that do different jobs,” he says.

The key areas of a hair follicle are outlined below:

(Image courtesy of Dr. Burg)

The body requires a lot of energy to get hair in a good place. “Ultimately, hair follicles are little machines geared up to manufacture hair shafts out of keratins. The follicles have to work extremely hard to do this 24/7, burning a lot of energy in the process. The body’s control over the process is complex and like anything complex, it can be quite easy to disrupt the balance and for things to go a little awry. This is part of aging, but it is also the root cause of hair loss and thinning,” says Dr. Burg.

“Individual hair follicles can be thought of as cycling, dynamic, independent mini organs,” he explains further. That is, all hair follicles on the human head independently go through a cycle of growth, rest, shedding and regrowth that occurs many times throughout life. While in many animals (like cats and dogs) the hair cycle is seasonal and relatively synchronized resulting in molting, the hair cycle in humans is not synchronized and hair follicles on your head will all be at different points in the hair cycle. “This means that humans will shed about 100-120 scalp hairs a day, every day of the year,” says Dr. Burg – and I suddenly feel more chill about my post-shower hair cluster.

Hair Growth Cycle

(Image courtesy of Dr. Burg)

Dr. Burg explains that the hair cycle is a repeating pattern of growth, rest and fall that happens many times over your life, with the average hair cycle being 6 or 7 years in length. The hair on the head is not cycling in unison, rather the hair cycles asynchronously, with each hair following its own timing and pattern. This leads to the loss of about 100 hairs a day, which is completely normal — if this sounds like a lot, you have to remember that you have around 100 000 to 150 000 hairs on your head, so this only represents 0.1% of your total hair, and after they fall they are generally replaced by a new hair growing in its place. “Each new hair is regenerated from a reservoir of different types of stem cells epithelial and mesenchymal, that live near the bulge region and dermal papilla, respectively,” he emphasizes.

If you really want to know about how your hair functions, you have to familiarize yourself with the growth phases, summarized by Dr. Burg.

Anagen: The anagen phase is the growth phase of the hair where the hair fiber is growing and elongating. In a normal adult, about 80% of the follicles on the head will be in anagen at any given time. The anagen phase for scalp hair follicles usually lasts for between 5 and 7 years.

Catagen: In the catagen phase, the hair stops growing and goes through a process known as regression that lasts about 10 days. During regression, the dermal papilla detaches and the follicle shrinks. About 1% of the hair follicles on the head will be undergoing catagen.

Telogen: Telogen is the resting phase of the hair cycle where the follicles are relatively dormant for approximately 2 to 4 months. Approximately 9% of the hair follicles are in Telogen at any given time. During telogen the stem cells from the bulge come into proximity to the remnant dermal papilla cells and when a critical concentration of growth signaling molecules is reached, the new hair follicle (also called a hair germ) migrates downwards and a new hair begins to form.

Exogen: As a new hair is forming in the telogen phase, the old hair is gradually released and pushed out. This shedding of the old hair shaft to make way for a new one is known as exogen, or sometimes called kenogen.

Signaling in the Hair Cycle

“The different stages in the hair cycle are mediated by signaling molecules and growth factors,” he continues. “The concentrations of these molecules in and around the cells in the hair follicle changes during the hair cycle, and this invokes the specific hair cycle events in the different parts of the follicles.” In general, there are two main types of signaling molecules: positive regulators which tell the cells to grow divide and produce the hair shaft and negative regulators that tell the cells to stop growing and rest, illustrated here.

(Image courtesy of Dr. Burg)

If the hair cycle is the center of hair growth, it is also at the forefront in hair loss. The hair cycle has quite a complicated physiology and biochemistry, and like anything complicated, it is very easy to upset the balance and get out of control. Things like changes in diet, stress, hormones, and the aging process can upset the hair cycle. “What we see in almost all forms of hair loss and hair aging is shortening of the growth phase of the hair cycle. When the growth period becomes too short, hair falls out too quickly, excess shedding occurs, and the regenerating hair comes in finer and is less substantial. Unfortunately for some, follicles can become so dysfunctional that they no longer produce hair at all. Once you have reached this stage the only option is hair transplantation,” he notes.

“At evolis our breakthrough technology revolves around one of the key players in the hair cycle hair cycle dysfunction and hair loss: a special molecule called fibroblast growth factor 5, or FGF5 for short,” he says. FGF5 is what is known as a negative regulator of hair growth and is often referred to the “master regulator” of the hair cycle. The only job of FGF5 is to tell hair to stop growing and start resting. So too much FGF5 means that there is more hair fall, less hair growth, slower hair growth, and the growth of finer, less substantial hair. “We also know of a FGF5 is hair specific, meaning it doesn’t have any other jobs in the body. Its only job is to signal hair to slow down, stop growing and start resting. The fact that FGF5 is hair specific means that it can be targeted without unwanted effects in other parts of the body. In fact, humans that naturally don’t have any FGF5 are healthy, but are just super hairy with fast growing hair and amazingly long eyelashes!”

All About Keratin

Aside from the live part of the follicle mentioned above and the pre-follicle stem cells, hair is essentially made of keratin – a hard structural protein.

The hair fiber has three distinct layers, which Dr. Burg describes. “The majority of the hair fiber is represented by the elongated keratinized keratinocytes: These hair cells form the cortex. The cortex is surrounded by different keratinized cells, which form the cuticle. Thick human hairs can have another cell type at their center, which form a structure known as the medulla. This is not present in all hairs, but is sometimes found in terminal hair”

(Image courtesy of Dr. Burg)

While we’ve heard a ton about keratin, you probably are unsure of exactly what it is. “Keratins are a family of proteins whose role is to provide structure and rigidity,” says Dr. Burg, noting that proteins are the body’s building blocks and that DNA is actually a recipe that your body uses to build proteins. “The human genome codes for around 20,000 different proteins that have a variety of functions in the human body, from converting sugars to energy, to fighting disease, to making more proteins, “ he says. You might remember from actual bio that proteins are made from combinations of amino acids, of which there are 20 different types — of these, the various combinations of amino acids in different chain lengths gives rise to the huge diversity in protein shapes, functions and activities.

“There are 54 different types of keratin proteins and these have a range of different roles in the body,” he continues. The main role of keratin is to provide strength and structure to the skin, nails, and hair, and also in many different cell types in the body. In animals, horns are often made of keratins as well.

“One of the reasons keratin is so strong is because it contains a high amounts of the sulfur containing amino acid cysteine (human hair is

14% cysteine). The cysteine forms very strong cross links with other cysteine amino acids (known as disulfide bridges), which helps give keratin its rigidity and strength. Keratin proteins in the hair have high numbers of helical structures with the disulfides bridging between the coils of the helices giving strength to the molecule,” he says.

(Image courtesy of Dr. Burg)
The amino acid Cysteine, with the sulfur group circled in red (Left) and models of keratin 85 (right), one of the main hair cuticle keratins. Top right is a generalization of the helical structures and bottom right is the molecular ball and stick model

The Scalp’s Role in Hair Growth

The scalp is the environment in which the hair follicle organs are situated and scalp tissue acts as a media through which growth factors diffuse, allowing various cell types, such as immune cells, move around performing housekeeping duties and defense. “That scalp, as an extension of your skin, is the first line of defense against the environment and as such, can be impacted by the environment. Things like sunburn, harsh chemicals, pollution and our beauty routines can all cause changes in the scalp that lead to things such as imbalance in the microbiome and inflammation,” he explains.

This is where the microbiome comes in. The term microbiome refers to the ecosystem of microbes (bacteria, fungi and small creatures) that live on and in the human body. A good balanced microbiome will out compete and fight off bad microbes, maintain a healthy pH and can actually work in concert with your immune system to maintain scalp and follicle health. However, imbalances in the scalp microbiome are known to be associated with dandruff, skin inflammation and seborrheic dermatitis. “Harsh chemical detergents or too frequent deep washing of the scalp with strong cleansers, can upset the microbiome, causing imbalance,” he confirms.

Like with most health issues, inflammation is using an underlying influence. “Inflammation is a generalized immune response to insult or injury,” says Dr. Burg. “Inflammation sets up a whole range of signaling and repair processes in the body. When there is a low level of chronic inflammation, from repeated sunburn, use of harsh cleansers, heat styling, tight hairstyles and the like aberrant signaling can begin to occur in the hair cycle, resulting in hair cycle imbalance. In this way, inflammation and irritation of the scalp can impact the way that follicles grow and cycle, which impacts overall hair health,” he adds.

Hair Loss, Cause and Prevention

“Hair biology is complex, we actually know only a little about how hair grows, cycles, ages and why we experience hair loss,” continues Dr. Burg. “What we do understand is that at the center of it all: almost all forms of hair loss and hair aging is shortening of the growth phase of the hair cycle. When the growth period becomes too short, hair falls out too quickly, excess shedding occurs, and the regenerating hair comes in finer and is less substantial.”

Recognizing hair loss is key. The first signs of an issue in women can be a widening of the part, more hair in the brush, or you may notice that your ponytail has become thinner. “For many women, a short growth phase also means they can’t grow their hair past a certain length, e.g. not past the shoulders. In men, increased hair in the shower, comb and on the pillow, as well as being able to see their scalp shining under bright lights are often signs that hair loss is occurring.”

“For men there is thought to be a strong genetic component of hair loss, but this is also quite complex and still relatively poorly understood, but some recent very large studies of the genes of men with early, severe hair loss have uncovered around 150 genes that appear to contribute to the problem, including the androgen receptor (which responds to Dihydrotestosterone – DHT) and other factors including the hair cycle regulator FGF5, and interestingly some genes involved in the metabolism of vitamin D,” he says. However, genes aren’t the only factor contributing to hair loss with things such as stress, poor diet, medications, severe illness/surgery also contributing and, with many men, aging is also a strong contributing factor. While hair loss in men can have a variety of contributing factors, the end result and process tends to follow the same path and also tends to occur over the same pattern, with the hair at the crown and front of the head being lost first.

Other Contributing Hair Loss Factors, According to Dr. Burg:

Hormonal changes – this can happen after and during pregnancy, when starting or changing contraceptive medication, or during menopause. Changes in hormone levels alter the body’s signals in truly profound ways, affecting many peripheral processes including the hair cycle.

Hereditary factors – some women have hair loss that runs in families, similar to the situation in men, the specific genetic factors associated with this are not well known or well-studied. In men the situation is complex with >100 genes involved, and it is highly likely that hereditary hair loss in women is equally as complex

Diet – yo-yo or extreme dieting can lead to hair loss in many women, as the body shuts down hair growth to direct nutrients to the organs. A balanced diet is critical for strong, healthy hair growth. It is important to maintain healthy levels of the B vitamins such as biotin, as well as Zinc, Iron, and vitamin E

Stress – extremely stressful events can result in hair loss. Generally, the stress levels have to be very high for the impact to be large, such as the death of a loved one, a divorce or bankruptcy. Stress promotes high levels of cortisol, which when combined with a “fight or flight” energy preservation strategy, can result in the body shutting down hair growth in favour of other organ functions.

Illness – any periods that put stress on the body can affect hair growth. Similar to the situation in extreme dieting and stress, the body shuts down hair growth to preserve energy. Treatments for cancer such as chemotherapy are well known to cause a temporary hair loss, but in many cases the hair will not grow back as strongly as before. A special case for women is ongoing hormonal treatment following breast cancer. These can cause ongoing hair challenges.

Separate to the issue of hair loss is hair greying. Hair greying happens as we age and as our hair goes through multiple cycles. As the hair cycles, falling and re-growing again, we gradually lose some of the special pigment producing cells known as melanocytes. Melanocytes produce two pigments, eumelanin (brown/black) and pheomelanin (red), which together account for all the different hair colors when combined in different quantities. As we start to lose melanocytes, hair-by-hair, our pigmented shafts are replaced by grey ones. These hairs are not actually grey but clear/ colorless. Unfortunately, no one has worked out how to stop this process from happening.

A Lifetime of Hair Changes

Here’s what Dr. Burg wants you to expect from your hair as you age.

Hair will generally be at its best in the early 20’s where hair is cycling with a long growth phase and growing quickly. Hair shafts are thick, and cuticles are tight. Hair challenges can occur in your 20’s due to stress, for example college exams and break ups, dieting. Often, hair changes occur as a result of the contraceptive pill or active IUD’s, which all can interrupt the hair cycle, leading to increased hair fall, poor quality growth and thinning. Some men have a strong response to androgens at this age these are thought to be a driver of difficult to treat early onset male hair loss.

Pregnancy, childbirth and breastfeeding change the hormones in the body, which can profoundly affect the hair cycle, leading to excess shedding and hair thinning. Pregnancy also affects the oil glands that lubricate and moisturize hair, with hair becoming more lustrous and beautiful during pregnancy, followed by a big change after childbirth where hair becomes dull and more brittle. Towards the end of the 30’s the hair follicles will also begin to get tired, grey hairs will start appearing and the hair may also start to thin out as the hair cycle changes.

Hair shafts can become more brittle and prone to breakage, cuticles less tight and hair may also become dull. The associated coloring that many women regularly perform damages the hair further. In addition, hair follicles are becoming increasingly tired, more grey is appearing and thinning may become noticeable. By the time many women and men notice thinning at this point, they have already lost 30-50% of their follicles.

Hair growth rates decrease, hair follicles become more tired, and towards the middle and end of the decade, menopause often begins. These factors combine to result in a shorter hair cycle, more hair fall, shorter maximum length and dull brittle hair as the oil glands change their production. Many people are completely grey by this point, as their melanocytes have disappeared

In the decade of the 60’s menopause is complete metabolism slows and with these there are more changes to the hair. With menopause comes a drop in the female hormones (estrogens etc.), leading to a relative increase in the influence of testosterone. Testosterone can affect women’s follicles in the same way as in some men, so a proportion of susceptible women will experience some hair loss due to this. In the 60’s hair will also be noticeably more brittle and dry, hair fall may be increased and for some women their hair will be quite noticeably, thinner meaning that hair style choices change to cover up the effects many men will notice a slow decline in the density and thickness of their hair

Hair SOS

Apart from choosing products that look after the hair cycle, prevent oxidative damage and nourish the follicles, such as the FGF5 blocking évolis range, there are a number of things that can be done to look after the hair, outlines Dr. Burg.

Eat a balanced diet: a balanced diet will be rich in B vitamins, Zinc, iron, and the other trace elements important for hair growth. After menopause, natural dietary sources of phytoestrogens such as flax seeds can also be beneficial

Get plenty of exercise: exercise boosts metabolism, which is important for rate of hair growth. Exercise also reduces stress levels, preventing stress hormones from shortening your hair cycle

Be kind to your hair: Avoid too many harsh chemical treatments. If you are going to wear extensions or weaves make sure that these are not too heavy. Heavy extensions can place traction stress on the follicles, leading to damage and potentially follicle death.

Use gentle naturally based cleansers: Natural is best! Avoid things like SLS and SLES, as well as parabens and silicones (often seen as dimethicone on the label), which can build up in the pores and cause further problems. Silicones can also weigh thinning hair down, which is not ideal. Ensure you are using products with natural antioxidants to fight the signs of aging. Also be careful not to wash too often as this can strip out the natural oils, resulting in brittle hair and breakages.

Iron: Deficiency and toxicity

Iron is an essential nutrient that is vital to the processes by which cells generate energy. Iron also can be damaging when it accumulates in the body. In fact, iron is a problem nutrient for millions of people. Some people simply don’t eat enough iron-containing foods to support their health optimally while others have so much iron that it threatens their well-being. The principle that too little or too much of a nutrient is harmful seems particularly apropos for iron.

Iron has a knack of switching back and forth between two ionic states. In the reduced state, iron has lost two electrons and therefore has a net positive charge of two. Iron in the reduced state is known as ferrous iron. In the oxidized state, iron has lost a third electron, has a net positive charge of three and is known as ferric iron. Because iron can exist in different ionic states, iron can serve as a co-factor to enzymes involved in oxidation-reduction reactions. In every cell, iron works with several of the electron-transport chain proteins that perform the final steps of the energy yielding pathways. These proteins transfer hydrogens and electrons from energy- yielding nutrients to oxygen, forming water and, in the process, make ATP for the cells’ use. If you recall from my previous article on this website, ATP is adenosine triphosphate, the cellular energy currency of the body. A direct precursor to this substance is nicotinamide adenine dinucleotide (NADH).

Most of the body’s iron is found in two proteins: hemoglobin in the red blood cells and myoglobin in the muscle cells. In both, iron helps accept, carry and then release oxygen. Iron also is found in many enzymes that oxidize compound reactions so widespread in metabolism that they occur in all cells. Enzymes involved in the making of amino acids, hormones and neurotransmitters require iron.

Iron absorption and metabolism:

The body conserves iron zealously and has devised many special provisions for its handling. Two special proteins in the intestinal mucosal cells help the body absorb iron from food. One protein called mucosal ferritin receives iron from the GI tract and stores it in the mucosal cells. When the body needs iron, mucosal ferritin releases some iron to another protein, called mucosal transferrin. Mucosal transferrin transfers the iron to a carrier in the blood called blood transferrin, which transports iron into the rest of the body. Intestinal mucosal cells are replaced approximately every three days. When the cells are shed from the intestinal mucosa and excreted in the feces, they carry some iron out with them. The iron holding capacity of these cells provides a buffer against short-term changes in iron need or supply.

Let’s quickly examine iron routes and storage centers in the body to further understand its absorption and metabolism. Iron in food reaches the intestinal cells during digestion where some is stored in intestinal cells in ferritin. Some iron is lost during the shedding of intestinal cells. If the body needs iron, it is packaged into transferrin, a transport protein, and carried in the blood. From here, some iron is delivered tothe myoglobin of muscle cells and bone marrow which then incorporates iron into hemoglobin of red blood cells, of which excess is stored in ferritin and hemosiderin. Iron containing hemoglobin in red blood cells carries oxygen. The liver and spleen dismantles red blood cells and packages iron into transferrin, and the cycle begins again. Some losses of iron occur via sweat, skin, bleeding, urine and the shedding intestinal cells.

Heme and non-heme iron:

How much iron is absorbed depends in part on its source. Iron occurs in two forms in foods, heme and non-heme. Heme iron is found only in foods derived from the flesh of animals, such as meats, poultry and fish. Non-heme iron is found in both plant and animal foods. Heme iron is so well absorbed that it contributes significant iron to the body. It is absorbed at a relatively constant rate of about 23 percent. The rates of absorption of non-heme iron are lower, ranging from 2 percent to 20 percent, and are strongly influenced by dietary factors and body iron stores. People with severe iron deficiencies absorb heme and non-heme iron more efficiently and are more sensitive to dietary enhancing factors than people with better iron status.

Absorption enhancing factors: MFP and vitamin C

Meat, fish and poultry contain not only the highly bioavailable heme iron, but also MFP factor that promotes the absorption of non-heme iron from other foods eaten with them. Vitamin C, which also enhances non-heme iron absorption from foods eaten in the same meal, is the most potent promoter of non-heme iron absorption. Vitamin C captures iron and keeps it in the ferrous form, ready for absorption. Other factors that enhance non-heme iron absorption include citric acid and lactic acid from foods, as well as HCl from the stomach.

Absorption inhibitors:

Some dietary factors bind with non-heme iron, inhibiting absorption. These include the phytates and fibers in whole grain cereals and nuts, the calcium and phosphorus in milk and supplements, the EDTA in food additives, and tannic acid. Tannic acid is present in tea, coffee, nuts, and some fruits and vegetables. Recent studies reveal that soy may inhibit iron absorption.

If absorption cannot compensate for losses or low dietary intakes, and body stores are used up, then iron deficiency sets in. Because so much of the body’s iron is in the blood, iron losses are greatest whenever blood is lost. Bleeding from any site incurs iron losses. Active bleeding ulcers, menstruation and injury result in iron losses.

Women are especially prone to iron deficiency during their reproductive years because of repeated blood losses during menstruation. Pregnancy places iron demands on women as well because iron is needed to support the added blood volume, the growth of the fetus and blood loss during childbirth. Infants and young children receive little iron from their high milk diets, yet extra iron is needed to support their rapid growth. The rapid growth of adolescence, especially for males, and the menstrual losses of teen females demand extra iron that a typical teen diet may not provide.

Assessment of iron deficiency:

Iron deficiency develops in stages. In the first stage of iron deficiency, iron stores diminish. Measures of serum ferritin reflect iron stores and are most voluble in assessing iron status.

The second stage of iron deficiency is characterized by a decrease in iron being transported within the body. Serum iron falls, and the iron carrying protein transferrin increases (an adaptation that enhances iron absorption). Together, these two measures can determine the severity of iron deficiency the more transferrin and the less iron in the blood, the more advanced the deficiency.

The third stage of iron deficiency occurs when the supply of transport iron diminishes to the point that it limits hemoglobin production. Now the hemoglobin precursor, erythrocyte protoporphyrin, begins to accumulate as hemoglobin and hematocrit values decline.

Iron deficiency and anemia:

Iron deficiency and anemia are not the same. People may be iron deficient without being anemic. The term iron deficiency refers to depleted body iron stores without regard to the degree of depletion or to the presence of anemia. The term anemia refers to the severe depletion of iron stores that results in a low hemoglobin concentration. The red blood cells in a person with iron deficiency anemia are pale and small. They can’t carry enough oxygen from the lungs to the tissues, so energy metabolism in the cells falters. The result is fatigue, weakness, headaches, apathy, pallor and poor resistance to cold temperatures. Since hemoglobin is the bright red pigment of the blood, the skin of a fair person who is anemic may become noticeably pale. In a dark skinned person, the eye lining, normally pink, will be very pale.

Overview of iron deficiency symptoms:

Eyes: Blue sclera (sclera is a tough fibrous tissue that covers the white of the eye, blue sclera has an abnormal degree of blueness).

Immune system: Reduced resistance to infection.

Nervous/muscular systems: Reduced work productivity, reduced physical fitness, weakness, fatigue, impaired cognitive function, reduced learning ability, increased distractibility, impaired reactivity and coordination.

Skin: Itching, pale nail beds and palm creases, concave nails, hair loss, impaired wound healing.

General: Reduced resistance to cold, inability to regulate body temperature, pica (clay eating and ice eating).

The body normally absorbs less iron if its stores are full, but some individuals are poorly defended against iron toxicity. Once considered rare, iron overload has emerged as an important disorder of iron metabolism.

Iron overload is known as hemochromatosis and usually is caused by a gene that enhances iron absorption. Other causes of iron overload include repeated blood transfusions, massive doses of dietary iron and rare metabolic disorders. Additionally, long-term overconsumption of iron may cause hemosiderosis, a condition characterized by large deposits of the iron storage protein hemosiderin in the liver and other tissues.

Iron overload is most often diagnosed when tissue damage occurs, especially in iron-storing organs such as the liver. Infections are likely to develop because bacteria thrive on iron-rich blood. Ironically, some of the signs of iron overload are analogous to those of iron deficiency: fatigue, headache, irritability and lowered work performance. Therefore, taking supplements before measuring iron status is clearly unwise.

Other common symptoms of iron overload include enlarged liver, skin pigmentation, lethargy, joint diseases, loss of body hair, amenorrhea and impotence. Untreated hemochromatosis aggravates the risks of diabetes, liver cancer, heart disease and arthritis.

In the United States, an estimated 10 percent of the population is in positive iron balance, with 1 percent having iron overload. Iron overload is more common in men than women and is twice as prevalent in men as iron deficiency. Some researchers have expressed concern about the widespread iron fortification of foods. Such fortification does make it hard for people with hemochromatosis to follow a low-iron diet but equal dangers lie in indiscriminate use of iron supplements.

Blood letting is the best treatment for hemochromatosis along with following a low-iron diet designed by a certified nutritionist containing substances that interfere with iron absorption. Some examples of substances that block iron absorption in such a diet include black tea, phytic acid found in whole grains, taking calcium with meals containing iron, and reducing vitamin C intake.

Iron recommendations and intakes:

  • Infants up until 6 months require 6 mg per day. From 6 months to 1 year, 10 mg is required.
  • Children age 1 to 10 require 10 mg per day.
  • Males age 11 to 18 require 12 mg per day.
  • Males age 19 to 51+ require 10 mg per day.
  • Females age 11 to 50 require 15 mg per day.
  • Females older than age 51 require 10 mg per day.
  • Pregnant women require 30 mg per day.
  • Lactating women require 15 mg per day.

Iron in selected foods:

Meat, poultry and fish will contribute highly absorbable iron. Legumes, dark green leafy vegetables, green beans, tomato juice, parsley, artichoke, dried fruits and corn flour contain respectable amounts of non-heme iron.

At the Hoffman Center, iron supplements are employed in a clear deficiency state, especially when dietary sources are not prevalent in one’s diet. Iron supplements can induce gastrointestinal distress. Common iron supplements are ferrous fumarate, ferrous sulfate and ferrous gluconate. Our choice is a product called slow iron, which is enteric coated and poses the least risk of gastrointestinal upset. Iron supplements should never be taken without the direct recommendation of a doctor.

Has anyone ever taken too many iron supplements?

I [20F] am a vegetarian, transitioning to vegan, who has had iron deficiency anemia several times in the past.

About six months ago, I began experiencing similar symptoms to what I experienced when I had anemia a few years ago. I decided to take a multivitamin to see if this helped, but the ones I liked didn’t have iron. Therefore, I decided to take a separate iron supplement in addition to this. My mom bought one for me and it was 65mg.

I have been taking this daily for the past six months. I attend college and the food here is not vegan friendly, so I knew I wasn’t getting enough iron and protein from their vegan food. Therefore, even after feeling better, I thought I was doing a good thing by continuing to take them.

It did not strike me to look this information up until I noticed my stool was foul smelling in a chemical/metallic way. This started a few weeks ago.

After googling results, I am now absolutely terrified. I do not have any symptoms of organ damage, but am still freaking out. I am going to urgent care as soon as it opens to get a blood test, but I really would like some peace of mind to help me sleep.

Is it likely that I actually damaged something permanently? I do get headaches occasionally and sometimes have gastrointestinal issues, but I attributed those to having covid a couple of months ago or to ongoing IBS struggles.

Nothing else has been out of the ordinary.

Can this be undone? How long will it take? Is it possible that I was iron deficient and that I hopefully have normal/close to normal levels?

Please do not judge or berate me as I had no reason to think that something found naturally in foods could be dangerous in excess. Nor did I think to check and see if 65mg was excessive. I know I messed up big time. I’ve already dumped the bottle out and won’t be touching another iron pill again. I’m already feeling stupid about having to explain to the doctor that I made a horrible mistake and I don’t want to feel any more hesitant to reach out to urgent care.

Can organ-accumulated iron get shed again? - Biology


A brief review of salient points regarding the origin of life:

Cosmic calendar: Earth formed 4.6 billion years ago there has been a long time for life to evolve. It took about a billion years to get through the early stages of chemical evolution such that there is some form of self-replicating system (e.g., a primitive living thing in its simplest definition). Miller experiments lead to formation of amino acids under lab conditions simulating a primitive earth atmosphere. Subsequent reactions could produce short polymers of the amino acids. When polymers are heated to 130°C to 180°C and then cooled in water to 25°C - 0°C proteinoid microspheres form. These provide evidence that simple cells could have formed from some of the earliest compounds.

Progress has also been made on the synthesis of nucleic acids. One significant bit of evidence, much further down the line, was the discovery of catalytic RNAs that performed enzyme like functions. This, and other evidence, suggested that RNA may be ancestral and DNA is a derived molecule for the storage of genetic material.

By 3.2 billion years ago, first procaryotes (Bacteria, blue green algae). By 2.5 - 2.0 billion years ago, communities of procaryotes emerge. e.g. Stromatolites as colonies of Blue green algae , formed biosedimentary domes of calcium carbonate = some of the earliest fossils. Photosynthetic bacteria have significant effect on the earth's atmosphere and the subsequent evolution of life. Blue green algae are photosynthetic and produce oxygen as a waste product. This was initially a poisonous molecule (as environment was an anoxic one) Lead to the production of an oxidizing atmosphere.

Large amounts of Oxygen oxidize the vast quantities of dissolved iron in the oceans: i.e., the oceans "rust." This counteracts the poisonous atmosphere problem, but only until the reservoir of iron is depleted and the iron settles out as the banded ironstone formation = layers of iron which form iron ore deposits. Ultimately, with the absence of iron to oxidize, the oxygen builds in the atmosphere and produces an ozone layer. This is a singular event which eukaryotes will ultimately take advantage of in the form of oxidative respiration. Subsequent cellular (at this time = organismal) evolution is contingent on this singular event. If we started earth over again, would this event re-occur? at the same time?, if not would we have evolved.

1.5 Billion years ago, a diverse flora of Eukaryotes present as asexual species. 1.4 By eukaryotic algae present. First metazoans seen in the Ediacara fauna for Australia (680 MyrBP).

Before considering the diversity of fossils we need to think about how representative the fossils are of past life which is largely a function of what gets preserved and where it might get preserved.

What gets preserved? Hard parts , and other parts that can be mineralized. Sequence of events from death to scavenging to decay to covering with soil. Example from heard of elephants : "wet" stage = two weeks (too much tissue for vultures so many invertebrates helped out). By the end of the third week, Dermestid beetles had removed all the skin and sinew from the bones. Within five weeks the temperature fluctuations caused the bones to crack and flake. Within one year the skeletons were completely disarticulated. Within two years many bones were covered with soil. Current day events can shed light on the fossilization process.

Fossilization : percolation of mineral grains (e.g. calcium carbonate) into interstitial spaces of hard part tissue. In bone the mineral is calcium phosphate which can incorporate fluorine, present in minute amounts in water, into the Calcium Phosphate to produce a crystal more resistant to erosion.

Death assemblage : become fossils at a site away from their actual habitat due to death and transport to an area. Life assemblage : organisms preserved in their natural habitat. Obvious example: If large mammal bones were found scattered among fossil fish, one presumably would not invoke the existence of primitive mammals that walked on lake or ocean floors!

Environments: fossils are generally restricted to areas of deposition. Upland areas less likely to preserve fossils: more erosion. In deserts material is covered by sand and has a good chance of being fossilized. In shallow seas sediment is being deposited and can cover skeletons. Some of the best fossil assemblages are from shallow sea deposits, lake beds, outwash plains from periodic river floodings, etc.

Ediacara fauna (640 MyBP) Many forms that bear some resemblance to modern phyla. Appears as if it were a major "evolutionary experiment" that did not work as it appears that none of their representatives made it into the Cambrian.

Burgess shale (530 MyBP, British Columbian rockies) Discovered in 1909 by Charles Doolittle Walcott: remarkable diversity of many different forms. Some of these are represented today many others are not (about 15-20 distinct, and now extinct, phyla ). e.g. Hallucigenia , Opabinia, Yohoia, Pikaia (first chordate), etc. Nicely illustrate the nature of Contingency (see S. J. Gould, Wonderful Life , 1989, Norton). The " iconography of the cone " led Walcott to erroneous pigeonholing of the Burgess shale organisms into "known" groups. The more appropriate image is " decimation " where only some organisms get through alive and those that do may be simply lucky. Harry Whittington in the 1960s and 1970s with Simon Conway Morris in the mid to late 1970s reanalyzed Walcott's collections. Concluded that there were many unique morphologies so new that they deserve the status of new phyla! . Many of Walcott's classifications were wrong. What would have happened if Pikaia had not made it through the "decimation"? (would you be here reading this? Another example of contingency ).

Other important points in interpreting the fossil record: Dating fossils requires radiometric dating of associated igneous rock . (sedimentary rock is of highly mixed origin). Moreover, fossils and the bed in which they lay have been reworked and redeposited. Careful stratigraphy and analyses of surrounding strata must be done to provide meaningful data about the relative and absolute ages of fossils. Gaps in the record . The nature of the fossilization process almost assures that there will be gaps in the fossil record. We have to live with it.

What do we know about fossil organisms? Certain associated information allows informed speculation about the biology of fossil organisms. Large dinosaurs that left tracks without tail dragging marks suggest an active lifestyle ? (other fossil remains do show clear evidence of tail dragging and footprints). Other assemblages show fossil bones of adults associated with nest sites and eggs: suggests parental care ? Simple footprints may seem like a cute form of fossil evidence. Actually a lot can be learned about the organisms: one can corroborate estimates of the animal's size one can measure distance between prints and obtain information about gait, travel speeds, etc. these interpretations further dictate a host of different physiological processes that might be able to sustain such a manner of locomotion. These types of issues are the main point of this lecture: from a small amount of fossil information, certain biological interpretations are implied simply by the necessary biological attributes that go along with a given footprint size, shape, etc.

Has anyone ever taken too many iron supplements?

I [20F] am a vegetarian, transitioning to vegan, who has had iron deficiency anemia several times in the past.

About six months ago, I began experiencing similar symptoms to what I experienced when I had anemia a few years ago. I decided to take a multivitamin to see if this helped, but the ones I liked didn’t have iron. Therefore, I decided to take a separate iron supplement in addition to this. My mom bought one for me and it was 65mg.

I have been taking this daily for the past six months. I attend college and the food here is not vegan friendly, so I knew I wasn’t getting enough iron and protein from their vegan food. Therefore, even after feeling better, I thought I was doing a good thing by continuing to take them.

It did not strike me to look this information up until I noticed my stool was foul smelling in a chemical/metallic way. This started a few weeks ago.

After googling results, I am now absolutely terrified. I do not have any symptoms of organ damage, but am still freaking out. I am going to urgent care as soon as it opens to get a blood test, but I really would like some peace of mind to help me sleep.

Is it likely that I actually damaged something permanently? I do get headaches occasionally and sometimes have gastrointestinal issues, but I attributed those to having covid a couple of months ago or to ongoing IBS struggles.

Nothing else has been out of the ordinary.

Can this be undone? How long will it take? Is it possible that I was iron deficient and that I hopefully have normal/close to normal levels?

Please do not judge or berate me as I had no reason to think that something found naturally in foods could be dangerous in excess. Nor did I think to check and see if 65mg was excessive. I know I messed up big time. I’ve already dumped the bottle out and won’t be touching another iron pill again. I’m already feeling stupid about having to explain to the doctor that I made a horrible mistake and I don’t want to feel any more hesitant to reach out to urgent care.