Vitamins: Sifting Through The Cure All ClaimsPam Black
Bolstered by an aging population and a push for preventive health care, vitamins have grown into a $4 billion industry, promising weapons against everything from colds to cancer. It's no small measure of their importance that vitamins have come under intense scrutiny from the Food & Drug Administration, which wants to impose standards on content and health claims. This effort is bitterly opposed by vitamin makers, who want to continue to police themselves, and by users who fear losing easy access to products.
Yet even as the opposing forces duke it out in the "war of the rose hips," the popularity of nutritional supplements is growing. Devotees go so far as to swear that vitamins can restore gray hair to its former color and let you lose weight while you sleep, even though much of the evidence is more anecdotal than scientific.
Sorting through the health claims is difficult even for the authorities. Hoping to clear up some of the confusion, the government is sponsoring a number of vitamin studies. Already, the FDA has approved claims that calcium supplements can reduce bone loss due to osteoporosis, and that daily doses of 0.4 mg of folic acid for pregnant women can prevent neural-tube birth defects of the spine and brain, such as spina bifida.
More exciting is the latest research showing that beta-carotene and vitamins E and C may help cut the risk of heart disease and some cancers. The theory is that as antioxidants, these substances stymie the formation of free radicals--molecules that are missing an electron, a void they fill by robbing other tissues, thereby damaging them. Antioxidants have extra electrons they donate to free radicals, which halts the damage. For example, vitamin E seems to prevent "bad" (low-density lipoprotein) cholesterol from oxidizing, or losing an electron, and binding to artery walls. And a recent study in China suggests the mineral selenium may reduce the risk of some cancers. But this may not apply in the U.S. because the study used a selenium-deficient population.
NEON LIGHTS. Scientists hesitate to vouch for some results until randomized testing is done. The risk of disease may have dropped for certain participants because of lifestyle--not the vitamin. "We can't exclude that some of this benefit is due to women [and men] being generally more health-conscious," says Dr. JoAnn Mason, co-director of women's health at Boston's Brigham & Women's Hospital, who found positive results in a cardiovascular study of nurses using antioxidants.
Even if future research bears out claims, nutritionists and scientists say you should be getting most of your nutrients from a healthy diet rather than pill-popping. "You can't smoke and be overweight and take E and not have to worry anymore," says Jeffrey Blumberg, associate director of the U.S. Drug Administration's Human Nutrition Research Center on Aging at Tufts University. A high-fiber diet containing five daily servings of fruits and vegetables should provide adequate antioxidants--except for E, which can't be consumed in food in doses as high as those used in tests (100 to 400 international units).
Vitamin proponents such as Dr. Earl Mindell, author of The Vitamin Bible, go further, saying that the government should do more to keep people from eating unhealthy foods. "They should put a giant neon sign on fast-food restaurants saying: 'This food is dangerous to your health,'" he says. It's unrealistic to think most people will eat properly, he adds, and vitamins provide a kind of insurance.
To hedge your bets, you might want to take a daily multivitamin with minerals. Tuft's Blumberg favors multivitamins with one to two times the U.S. recommended daily allowance. The Center for Science in the Public Interest in Washington recommends adding antioxidants. "Most scientists are still gun-shy about recommendations because the evidence isn't conclusive," says Bonnie Liebman, CSPI's director of nutrition. "But many are taking antioxidants, E especially, themselves." She advocates the levels employed in tests: 100 to 400 IU of E, 25,000 IU of beta-carotene, and, because the evidence is weaker for C, 250 to 500 mg--enough to saturate body tissues.
SUN SUBSTITUTE. It may be cheaper to buy your antioxidants separately from your multivitamin. But be sure to distinguish between vitamin A and beta-carotene, which are often lumped together as one dosage. Since beta-carotene makes as much A as you need, preformed A (listed as fish oil, acetate, or retinol) isn't necessary. It's not an antioxidant and can be toxic in high doses.
It's important to get at least the following minerals from your vitamin supplements: iron, zinc, copper, chromium, selenium, and magnesium, according to CSPI. Most people get other nutrients such as phosphorus, biotin, and chloride from food. Above all, be wary of taking too much of any one nutrient. While healthful in moderation, some nutrients disrupt the effects of others. And realize that "we need to know more about people taking large amounts over a long time," says Dr. William Harlan, nutrition coordinator at the National Institutes of Health.
Postmenopausal women may want to pay special attention to getting enough calcium to prevent osteoporosis. Studies suggest that vitamin D helps women retain calcium. CSPI says women living in northern climes may not be getting enough D from the sun in winter and hence should take up to 400 IU.
CSPI is one of the few organizations that can provide some signposts in the health-supplement jungle. Another source is the Consumer Nutrition Hotline (800 366-1655), backed by the American Dietetic Assn. It's staffed by a registered dietician who can answer questions and has recorded messages that relay nutrition news.
Otherwise, CSPI's newsletter, Nutrition Action, which mostly covers food, includes some valuable guidance on shopping for vitamins. For one thing, you should be able to get all the vitamins you need for $10 a month. Cheap vitamins are just as good as expensive ones. Safeway Central-Vites are identical to Centrum yet sell for less. All supplement makers buy their vitamins and minerals for a pittance from a few international companies. Marketers then brew up whatever doses they like--you can't even be sure you're getting the dose stated on the label. CSPI suggests sticking with the brands of big national retailers such as Kmart, Wal-Mart, and Safeway, which are fairly stringent about vitamin content.
E CHOICE. Ignore claims about natural ingredients--except with natural E, which the body metabolizes better than synthetic versions, according to some studies. Look for d-alpha-tocopheral (not dl-) on the label if you want natural E. But even synthetic E seems to be an effective antioxidant.
Check the rate at which vitamins dissolve in the stomach. Some have been known not to dissolve or be absorbed, hence providing no benefit. The U.S. Pharmacopoeia, which sets standards for drug com- position, offers dissolution rates that some vitamin makers have adopted voluntarily. Water-soluble vitamins such as the Bs and C should dissolve in 30 to 45 minutes. Standards for fat-soluble vitamins (A, D, and E) should be issued in 1994. According to CSPI, all vitamins made by P. Leiner Nutritional Products--about half of the store-labeled brands--dissolve well.
In the future, it may be easier to evaluate what's in a vitamin bottle and how it can help you. For now, there appears to be little risk in taking supplements in moderate doses. At worst, you'll simply enrich the vitamin makers. At best, you'll improve your quality of life.
GETTING THE PROPER DOSAGE COMMON OSAGE HEALTH VS. RECOMMENDED CLAIM DAILY ALLOWANCE TOXICITY COMMENTS VITAMIN A Promotes good Up to 5,000IU More than 10,000 Beta-carotene is vision, fortifies (RDA 5,000IU) IU can cause liver preferable mucous damage, possibly membranes birth defects VITAMIN B COMPLEX Strengthens Varies Can cause neuro- Take as group nervous system logical damage to avoid imbalance BETA-CAROTENE May help prevent 15-30mg Too much Better source of cancers and (No RDA) may turn vitamin A than heart disease skin orange premade A VITAMIN C May help Up to Above 5,000mg Best to buy prevent cancer, 1000mg may cause diar- the kind with heart disease, (RDA 60mg) rhea, kidney stones rose hips VITAMIN E Fights cancer and 100-400IU None Natural may work heart disease (RDA 30IU) better than synthetic DATA: FOOD & DRUG ADMINISTRATION, CENTER FOR SCIENCE IN THE PUBLIC INTEREST, THE VITAMIN BIBLE
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