Woman's WorldWoman's WorldBy Jean Talbert, M.D.
Grocery stores, pharmacies and health food stores contain shelf after shelf of vitamin and nutritional supplements. Advertisements tout the benefits of supplements to treat or prevent disease. News reports come out weekly on the newest benefit or risk. The information is so conflicting that it is hard to know what to do. Research is limited, but some large studies are underway to help sort out some of the questions.
What do we know so far?
Folic acid: Folate, the natural form of folic acid, is found in green leafy vegetables, fruits, cereals, whole grains, nuts and meat. It is an essential nutrient for normal cell division. Even mild deficiencies at conception have been associated with an increased risk of spinal bifida and other neural tube defects in the fetus. Beginning the supplements after a positive pregnancy test may be too late.
Efforts to increase folic acid in the typical American diet started in 1998 and since that time, the incidence of neural tube defects in this country has declined by 27 percent.
Folic acid may also be beneficial in lowering the risk of breast and colon cancers, especially among moderate alcohol consumers. The use of folic acid to prevent cardiovascular disease has been less conclusive. Folic acid does lower at least one known risk factor for coronary artery disease, but it does not appear to lower the incidence of cardiovascular events.
Calcium: Inadequate calcium intake contributes to decreasing bone density, osteoporosis, and an increased risk of hip and vertebral fractures. Studies show that calcium supplements help to prevent bone loss, but increase the risk of kidney stones.
Food is the best source of calcium because it is the easiest to absorb.
Supplements, such as calcium citrate or calcium carbonate are recommended when dietary calcium is inadequate.
To ensure adequate absorption, overly large doses of calcium should be avoided. Also, avoid natural forms of calcium such as bone meal or oyster shell because they may contain small amounts of lead or other heavy metals. Once osteoporosis has developed, calcium alone may not prevent fractures.
Vitamin D: Vitamin D can be obtained in diet or through the skin in younger adults from the sun. Many food products are fortified with vitamin D.
Vitamin D is essential for bone strength, but excessive doses can be toxic. For optimal benefit, it should be taken in conjunction with calcium. Reports show no benefit of calcium and vitamin D supplements in the prevention of colon cancer.
Antioxidant vitamins (vitamin A, C, E): Antioxidant vitamins are found primarily in fruits and vegetables. Studies of whether these supplements would protect against cancer and cardiovascular disease have not been encouraging.
Vitamin A may slightly decrease the risk of breast cancer, but lung cancer rates are increased. There is no apparent benefit with cardiovascular disease. High doses of the retinal form of vitamin A have been associated with birth defects and possibly hip fractures. Vitamin E studies show no clear benefit preventing cardiovascular disease, cancer or Alzheimer’s.
A recent report shows a slight increase in overall mortality in men and women taking high doses of antioxidant vitamins and this is not currently recommended.
Omega-3 Fatty Acids (Fish Oil): Fish oil has recently been promoted as protective against cardiovascular disease, particularly hypertension. Low doses lower serum triglycerides. Some limited studies show a decreased risk of cognitive impairment and Alzheimer’s disease in people consuming fish twice a week, but these have not been confirmed. Care should be taken in using these supplements as even low doses can increase the risk of bleeding.
Until more randomized studies are conducted to answer lingering questions, most preventive health experts recommend:
· A daily diet with five or more servings of fruit and vegetables.
· Reproductive age women should take a daily vitamin supplement containing folic acid.
· A daily multivitamin containing no more than 100 percent of the Recommended Daily Allowances of vitamins may benefit all adults. Generic forms generally are fine.
· Pre-menopausal women should take in 1000 mg. per day of calcium and 400-800 IU per day of vitamin D. Post-menopausal women should increase the calcium to 1200-1500 mg. per day.
· Only patients with documented vitamin deficiencies should take high dose supplements.
· Diets rich in fish oil may lower the risk of cardiovascular disease and dementia.
WARNING! Discuss all supplements with your health care provider to avoid possible negative interactions with prescription medication.
(Dr. Talbert is a board certified OB/GYN specialist practicing with Cape Obstetrics, Midwifery & Gynecology in Falmouth and Sandwich, 508-457-0088.)