Female Athletes and Amenorrhea

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By Jen our Resident Nutrition Writer

Women are becoming more and more involved in competitive sports and intense workout regimes, but with this rise, amenorrhea (loss of menses for at least 3 months) is also increasing. Amenorrhea from athletics can be due to a number of things such as a high physical demand, low body fat, and negative calorie balance. While some quickly say, “it’s a blessing,” that statement is a far cry from the truth; amenorrhea is associated with serious reductions in heart, reproductive, and bone health.

Being an athlete in a low body-weight driven sport, I know how hard finding the right balance can be. Furthermore, there is far too little information about the effects of excessive exercise and low body fat on female health out there, probably because our society typically praises thin and fit women. With that said, this article will be a resource for those struggling with amenorrhea as well as an eye opener for the rest.

Maintaining low body weight for performance and looks is common, especially in females. Increased energy expenditure without high enough calorie intakes will lead to an energy deficit, which is required for weight loss. While this is okay short term, a sustained negative net calorie intake eventually will result in a reduction of many important functions such as growth, reproduction, heat control, etc. In females, low energy causes a disruption in the hypothalamo-pituitary-gonadal axis that results in first irregular periods and then loss of menses all together. With body fat in mind, approximately 17% body fat (regardless of how heavy you are) is the minimum females need to maintain reproductive health, but for many sports, athletes are even below 12%.

Menstruation is a particularly sensitive function that is a sign of reproductive health. It requires complex interactions between the hypothalamus, pituitary, and ovaries. Menstrual dysfunction is characterized by reduced or absent luteinizing hormone (LH) pulses; decreased follicular development, ovulation, and luteal activity; and ultimately low levels of estrogen and progesterone. These changes result in a halt in endometrial proliferation and an absence in menses. The main factors for amenorrhoea in athletes are body weight, body fat, physical and psychological stress, and energy balance. Low-fat and high fiber diets also seem to decrease estrogen in the body by decreasing energy and usable fats to produce hormones (keep in mind, this is typically a good thing in most people).

So what’s the big deal about having a disruption in reproductive health while you’re young and not ready for kids anyways? Aside from a higher risk for heart failure, risk factors for low bone density and osteoporosis significantly increase with each missed period. Irregular periods are associated with a four-fold higher risk for stress fractures in athletes, and the prevalence of low bone density is even higher in females with amenorrhoea. Think I’m exaggerating about the effects of amenorrhea? Low bone density was actually found in 21.8% of American elite female athletes who were tested. Pre-menopausal females who have lost their period for 6 or more months should get a bone density scan done.

Bone remodeling begins at conception and is determined by both bone degradation and bone formation, which are crucial for maintaining the skeleton as well as blood calcium. Estrogen is vital for bone growth during early adolescence; bone mass doubles during puberty and peak bone mass occurs at about 17 years of age. Estrogen stimulates osteoblasts and inhibits osteoclasts, as well as increases growth hormone secretion; for this reason, a deficiency will favor demineralization. The effect of an estrogen deficiency during puberty is even greater and results in a much lower peak bone density. Although a restoration of menses in females with amenorrhea is associated with increases in bone density, at a certain point of bone loss, bone mass will not be fully restored.

But wait, I thought exercise helps increase bone density? To a point, that is most certainly true and certain exercises seem to be particularly effective at this. For example, weight-bearing and high-impact sports like gymnastics have positive effects on bone density, even when amenorrhoea is present, while the opposite is true for non-load bearing, endurance sports like running. Athletes who do weight-bearing activity are seen to have 5–15% higher bone mineral density than other athletes. The main reason for this variation between endurance and weight bearing sports is mechanical stress increases mineral deposits while promoting collagen production. The problem with exercise comes when you don’t get enough calories to support your physical demands. In exercising females, bone formation is supressed within 5 days of a calorie restriction while the rate of bone degradation is increased. Earlier onset of intense training (through and before puberty) with inadequate calories presents an even greater risk for low bone density.

Clearly amenorrhea should be taken seriously and managed quickly to avoid significant bone loss; what steps can females take? Treatment is highly individual according to age, sport, diet, and lifestyle. The most important adjustment is a higher net calorie intake, whether that comes from eating more, exercising less, or both. Hormone replacement therapy and oral contraceptives are the most commonly prescribed treatment but, while menses will return, there is very little evidence that this option will replace bone loss. When only estrogen deficiency is present without a calorie deficiency, less bone is lost than the reverse, when there is a calorie deficit but no estrogen deficiency. Calorie intake seems to be the most important contributor for bone health improvements.

Specific nutrients are also important considerations while managing amenorrhea. Higher fat diets support enhanced estrogen (made from cholesterol) in women, especially diets higher in omega-6s (contrary to what most Americans would want). Other than fat, adequate protein, vitamins, and minerals are required for bone health. Calcium and phosphorous are needed for mineralization, vitamin D for calcium absorption, vitamin C for collagen formation, and vitamin K and B12 for protein synthesis and calcium utilization. Calcium and vitamin D insufficiency are quite high in athletes; in fact, a study on adolescent gymnasts showed that 83% of them had vitamin D insufficiency and 72% of them had inadequate calcium intakes. While managing amenorrhea, supplementation with calcium, vitamin D (and K2), and possibly B12 if you’re a vegetarian, as well as eating more fruits, vegetables, and fatty and protein rich foods is important to maintain and enhance bone density.

To wrap things up, amenorrhea should be quickly managed with a higher intake of calories, fat, protein, and essential nutrients. If you have amenorrhea, take it seriously! Visit a doctor or naturopath, but make sure you’re equipped with information; many doctors still do not know how to adequately manage this problem (feel free to print this article out and bring it with you). Awareness for low body fat in female athletes has yet to appropriately addressed, given the pedestal most fit females are put on. By no means am I saying that female fitness is a bad thing, just that when fitness gets to the point of a loss of periods, something needs to be done for the sake of your long term health. Amenorrhea is not a blessing; more people need to see it that way.

This article can also be found on the Sunwarrior website! http://www.sunwarrior.com/news/female-athletes-and-amenorrhea/

Lambrinoudaki I, Papadimitriou D. (2010) Pathophysiology of bone loss in the female athlete. Ann N Y Acad Sci.1205:45-50.

Roupas N, Georgopoulos N. (2011) Menstrual function in sports. Hormones 10(2):104-16.

Turner L. (2011) A meta-analysis of fat intake, reproduction, and breast cancer risk: an evolutionary perspective. Am J Hum Biol. 23(5):601-8.

Vyver E, Steinegger C, Katzman DK. (2011) Eating disorders and menstrual dysfunction in adolescents. Ann N Y Acad Sci. 1135:253-64.

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