This article reviews current literature dealing with nutritional impact on women's health, including fertility. The author, Dr. Seibel, suggests that gynecologists and reproductive endocrinologists should become more familiar with studies on nutrition and nutritional supplements so that patients obtain necessary vitamins and minerals as part of their treatment.

First, the basics. To date, 13 essential vitamins have been identified, each of which is soluble (capable of being dissolved) in either fat or water. The fat-soluble vitamins are A, D, E, and K, and beta-carotene. The water-soluble vitamins include vitamins C, B1, B2, B3, B5, B6, B12, biotin, and folic acid. Fat-soluble vitamins can be stored in the body and can accumulate. Additionally, they are not easily destroyed by heat during cooking or processing, or through exposure to air. On the other hand, water-soluble vitamins usually do not accumulate in the body. They are stored only in small quantities, and this quality allows deficiencies of these vitamins to occur faster.

Consumers and clinicians have been given mixed messages about the necessity and safety of vitamin and mineral supplements. Some information has suggested that the increased amount of vitamin and mineral intake recommended during pregnancy can be by obtained solely through diet and that multivitamin supplements are not necessary. However, this information fails to take into account the fact that pregnant women have substantially increased nutritional requirements, that at-risk populations need supplements, and that nutrition and nutritional supplements are important immediately before conception and throughout the reproductive years.

Male reproductive health and nutrition has also been under-treated in medical studies and literature. One area that has been explored is the role of antioxidants in maintaining peak sperm movement. Another area that has been explored is the role of minerals and trace elements in male infertility. Minerals and trace elements like zinc, magnesium, and selenium have controlling or regulatory roles in the testes and other sex glands. However, excessive consumption of selenium supplements can have a harmful effect on semen quality. While it is clear that nutritional supplements have an important role to play in male reproductive health, the lack of definitive studies limits the extent to which this information can be translated into clinical practice.

On the other hand, the role of nutrition and nutritional supplements in women is somewhat better documented, but still limited. One study looked at endometriosis and the role of diet and drug therapy on related gastrointestinal symptoms. Women with endometriosis were studied who exhibited symptoms such as chronic abdominal pain, nausea, vomiting, bloating, and altered bowel habits. Dietary changes included the reduction of glycemic carbohydrates (such as rice, potatoes, pasta, corn, fruit juices, and beets), while balancing with omega-9 fatty acids. Caffeine and tyramine foods were eliminated (coffee, tea, colas, aged cheeses, liquor, mixed Chinese vegetables), and omega-3 fatty acids were included. They were also treated with drug therapy (clonazepam). Eighty percent of the women showed a significant reduction in symptoms after eight weeks of treatment.

The ratio of calcium to magnesium throughout the menstrual cycle has also been studied. That this ratio is increased at the same time as the estrogen peaks and the progesterone increases lends credence to the idea that this ratio is related to premenstrual syndrome. This increased ratio has also been associated with the onset of tension and migraine headaches. In fact, administering magnesium has been shown to be effective in treating these symptoms. In addition, calcium and magnesium could have significant roles in ovulation and spontaneous abortion that probably merit more investigation.

Nutritional deficiencies may also play a role in spontaneous abortion, one of the most common complications of pregnancy. The addition of vitamins and amino acids has been proven to have positive effects on the rate of conception and on helping women achieve significantly shorter conception times. Studies have shown that even subtle nutritional deficiencies can play an important role in early pregnancy loss. This suggests the importance of obtaining a detailed nutritional and nutritional supplement history from patients who have infertility and/or recurrent pregnancy loss. Nutritional risk factors to look out for include adolescent age, smoking, substance abuse, frequent dieting, vegetarian diet, diabetes, depression, and evidence of an eating disorder.

The period of periconception and pregnancy is one in which information about nutrition and nutritional supplements is most confusing. While some authorities do not recommend a routine daily multivitamin and mineral supplement, more recent and exhaustive studies have suggested that the routine use of a supplement that contains folic acid and zinc by women of child-bearing age could translate into a $2.6 billion savings on hospital charges. The supplements are significantly effective only when they contain folic acid in addition to dietary folate.

Following is an outline of vitamin and mineral supplements that should be consumed both before and during pregnancy:

MINERALS

Iron. Lack of iron affects over a billion people - as the most common nutritional deficiency in the world. In the U.S., Japan, and Europe, 10-20 percent of reproductive-age women are anemic. Iron efficiency is associated with poor pregnancy outcome. One study has suggested that as little as 36 percent of pregnant women adhere to an iron supplementation program.

There are many reasons why pregnant women require more iron, including the demands of the fetus, the placenta, and an expanding maternal hemoglobin mass. So, depending on the size of the woman in question, the total iron requirement can be around 800-1,000 mg. And her requirement can be 400 mg higher if she is anemic at the beginning of pregnancy.

To meet the pregnant body's demands, a woman should double the regular RDA of 15 mg daily to 30 mg daily. Iron is absorbed best when it is ingested (without milk, tea, or coffee) between meals or at bedtime. Along with the 30 mg of iron daily, 15 mg of zinc and 2 mg of copper are also recommended because iron can interfere with the absorption of these elements.

Calcium. Because of the diversion of ionized calcium to the fetus during pregnancy, calcium requirements increase by 200-300 mg daily. The RDA for calcium during pregnancy and lactation is 1,200 mg per day. Adolescents and lactose-intolerant women may benefit from an even higher intake of calcium. Supplementation of calcium has been associated with significant reduction in hypertension and the risk of preeclampsia. Since calcium supplements diminish iron absorption, sufficient iron intake should also be ensured.

Zinc. Low birth weight is associated with about 80 percent of perinatal deaths. Studies have indicated that zinc affects metabolic pathways, making it essential to growth. Low levels of the mineral have been strongly associated with fetal death, skeletal defects, central nervous system defects, and growth retardation in animal studies. A study with women in particular found that providing daily zinc supplements during very pregnancy to those with relatively low plasma zinc concentrations resulted in increased infant birth weights. On the basis of studies such as these, some specialists estimate that between 7-59 percent of all cases of low birth weight could be prevented through women's daily use of a multivitamin and mineral supplement containing 15-20 mg of zinc during the first trimester.

VITAMINS

Folic Acid. An essential vitamin, folic acid is necessary for normal metabolism, tissue turnover, and growth. The rapid growth of the placenta, fetus, uterus, and breasts during pregnancy increases the need for the vitamin. Doctors now know that inadequate nutritional intake of folic acid during the first few weeks of pregnancy increases the risk of neural tube defects. The risk of spontaneous abortion, pre-term delivery, and small-for-gestational age infant are also increased by low folic acid intake throughout pregnancy.

The good news is that there is a significant and positive relationship between the maternal intake of folic acid, plasma folate concentrations, and amniotic fluid levels. On average, Americans consume only 0.2 mg per day of folate. Foods rich in folate include spinach, turnips, mustard greens, and other raw, leafy vegetables. Citrus fruits are good sources, and beans and legumes such as lentils, pinto beans, and chick peas are good as well. More than half of the nutritional value, though, may be lost in the cooking process. Experts say that pregnant women should supplement their diets with 400-800 mg of folic acid per day.

Vitamin B12. This vitamin is essential for protein synthesis and normal cell division. It can be found only in foods that contain animal protein - like meat, fish, eggs, and milk. Levels of vitamin B12 normally decrease during pregnancy, but if a pregnant woman eats such foods, a sufficient level can be easily maintained. Those who might benefit from a vitamin D supplement (400 IU) are those who have abnormalities in gastrointestinal absorption, who exclude vitamin D-fortified milk, or are strict vegetarians, particularly if they breast-feed.

Vitamin B6. This is essential for protein, carbohydrate, and lipid metabolism, as well as immune function. A pregnant woman is more in need of this vitamin. Studies indicate that women in the U.S. consume less than the RDA for vitamin B6. Particularly at risk for deficiency are substance abusers, pregnant adolescents, and women with higher-order pregnancies. This vitamin can be found in meats (especially organ meats such as liver) and enriched grains, but during pregnancy a daily 2 mg supplement is still recommended. Supplementation of this vitamin has also been recommended to treat nausea and vomiting during the first trimester of pregnancy. However, a prolonged use of more that 200 mg per day can lead to numbness in the feet and hands and ifficulty in walking.

Vitamin C. Found in fresh fruits and vegetables, this vitamin is essential to many metabolic processes. However, drying, salting, cooking (especially in copper pots), mincing, and mashing fresh vegetables reduces the amount vitamin C. During pregnancy, vitamin C levels fall by 10-15 percent. The RDA of this vitamin is 70 mg per day, an amount that can usually be ingested through the diet without nutritional supplements. Some authorities recommend a supplement of 50 mg per day for women smokers, women who drink alcohol considerably, and long-term users of oral contraceptives. However, since vitamin C is actively carried to the fetus, vitamin C intakes should be less than a gram per day.

Vitamin A. Vitamin A is critical for normal growth and for eye and skin health. It is produced by the conversion of beta carotene. It is found in carrots and dark green, leafy vegetables as well as in eggs, milk, butter, and liver. The RDA for vitamin A is 2700 IU as retinol or 4,800mg of beta-carotene. Pregnancy does not create significantly more demand for vitamin A, so excessive intake of supplements is unneeded and unadvised.nIn fact, there has been concern that excess vitamin A taken by a pregnant woman might be toxic to the fetus. One study shows that an intake of more than 10,000 IU per day results in an increased risk of cranial, neural, and crest tissue-related abnormalities, but more study is needed before this can be called conclusive. The risk of vitamin A toxicity is relatively small, unless one consumes large amounts of animal protein in addition to large amounts of nutritional supplements.

Choline. Choline is an essential nutrient found in high concentrations in eggs, liver, peanuts, and various meats and vegetables. It aids in preventing losses that result from aging. It also appears to be important to the fetus during pregnancy, when it improves spatial and temporal memory as well as attention. Maternal levels of choline decline and need to be restored through diet or supplements. Sufficient choline should be ingested during pregnancy and after the onset of menopause.

Soy Isoflavones. Much attention and research has been focused on the potentially major benefits associated with isoflavones during the last six years. Soy is a significant source of isoflavones. Isoflavones can also be found in lesser quantities in over 300 plants. Prospective benefits include increased levels of sex hormone-binding globulin, reduced vaginal dryness, and less frequent hot flashes. Studies are also investigating their observed positive role in preventing breast and prostate cancer, osteoporosis, and other serious conditions.