By Sally Squires
Washington Post Staff Writer
Tuesday, May 23, 2006
If you're among the majority of Americans who regularly take a multivitamin and mineral pill, last week's conclusion by a federal panel that there's no evidence to recommend for or against these dietary supplements may leave you feeling a bit perplexed.
The report was written by a panel of 13 experts who were convened by the Office of Dietary Supplements and the Office of Medical Applications of Research at the National Institutes of Health to explore questions about patterns of multivitamin use and their effectiveness in a generally healthy population.
Before tossing your multivitamin pills into the trash, here's what you need to know from the 19-page report.
If I eat healthfully, do I need a multivitamin?
It's possible for most people to cover the nutritional bases with food alone, but you'll need to choose very wisely. For example, the 2005 Dietary Guidelines Advisory Committee found that adults and children typically fall short on vitamin E and the minerals calcium, magnesium and potassium. Adults also often don't get enough of vitamins A and C.
What does it take food-wise to meet the recommended intake?
This won't be easy. To start, figure on two cups a day of fruit and about 2 1/2 cups of vegetables, which means at least a serving at every meal plus more for snacks. Variety is essential. Dark leafy vegetables -- especially spinach, kale, chard and mustard greens -- as well as orange vegetables and fruit such as sweet potatoes and cantaloupe are especially important to eat at least two to three times per week. They provide beta carotene, folic acid and many other nutrients. Then you need three servings of whole grains each day. That could be met by eating a cup of oatmeal for breakfast and having a whole wheat sandwich at lunch. Three glasses of nonfat milk (or another calcium- and vitamin-D-fortified substitute, such as orange juice, soy milk, cheese or yogurt) will meet 90 percent of the daily calcium for adults 50 and younger. Nuts and healthy oil, such as olive or canola oil, go a long way toward providing the recommended daily amount of vitamin E.
Can I get eat all that food without going overboard on calories?
That's another challenge. Some scientists think it's tough to get all the nutrients you need from food alone. The guidelines committee did the calculations and found that with diligence it's possible to meet all the recommended intakes and still not overeat, but there are few calories left for splurges on desserts, soft drinks, alcoholic beverages or even a little margarine on your morning toast. How few? Just 181 calories for those who eat 1,800 calories daily -- or about the amount of calories found in one tall skim latte. At 2,000 calories daily, about 200 discretionary calories remain. The good news: If you boost physical activity, you may be able to eat a little more -- emphasis on the "little."
Did the multivitamins panel find that taking the pills can help prevent any chronic diseases?
Yes, but just a few.
· The panel underscored the importance of folic acid for all women of childbearing age. This B vitamin has been proven to help reduce the risk of birth defects that cause problems with the spinal cord and nervous system. Since 1998, foods have been fortified with folic acid, and rates of spina bifida and other neural tube birth defects have dropped. Women need 400 micrograms daily of folic acid -- about the amount found in one cup of lentils and one cup of cooked spinach--and also the amount provided by many multivitamins.
· The panel also said that one federally funded study of 3,600 people has shown benefits of taking high levels of the antioxidants vitamins A, C and E and also the mineral zinc to prevent some age-related vision loss , such as macular degeneration in people who already have early signs of the condition. In the study, participants took 500 milligrams of vitamin C, 400 IU of vitamin E, 15 milligrams of beta carotene and 80 milligrams of zinc daily. The vitamins reduced the risk of developed advanced macular degeneration by 25 percent. There was no effect in preventing cataracts.
· Calcium and vitamin D were also recommended for post-menopausal women . Both nutrients have been shown to help reduce the risk of bone fractures that often occur with osteoporosis. Current recommendations are for men and women 51 and older to consume 1,200 milligrams daily of calcium -- about the amount found in a quart of skim milk -- and 400 IU of vitamin D. Those 70 and older need 600 IU of vitamin D daily.
So if I eat fortified food and take a multivitamin, could I get too much of a good thing?
"We're concerned that some people may be getting too much of certain nutrients," said the panel's chair, J. Michael McGinnis. That's because a growing number of foods and drinks are fortified with vitamins and minerals. In 2005, the majority of Americans consumed fortified foods or beverages, which include bread, crackers, cereals, milk, eggs, juices and even fortified water. Among the nutrients whose consumption could easily exceed upper limits are vitamin A, high doses of which have been linked to an increased risk of osteoporosis. That's why experts say if you take a multivitamin, pick one whose ingredients don't exceed 100 percent of the daily value.
I read that as people age, some vitamins are not as well absorbed. What about that?
You're thinking of vitamin B12. After age 50, the stomach produces less acid; this reduces absorption of B12found naturally in food. But the crystalline form found in fortified food and in dietary supplements can be absorbed well at all ages. This is why the National Academy of Sciences recommends that people over 50either eat fortified food or take supplements. Many multivitamins contain 100 percent of the recommended daily intake, but the latest federal panel did not address vitamin B12in its report.
My multivitamin has lots of ingredients for which there is no daily value given, such as boron, lutein, lycopene and zeaxanthin. Are these useful or safe?
These ingredients are increasingly showing up in dietary supplements. They may have benefits (or hazards) that are suggested but not proven in the scientific literature. They may be there for marketing purposes, to set one multivitamin apart from the others on the shelf. In any case, the Institute of Medicine's Food and Nutrition Board has not set recommended dietary intakes for these substances.
Can multivitamins interact with drugs?
Adverse effects and drug or food interactions are enough of a concern that the panel recommended developing ways to understand and track them. These and other safety concern also prompted the panel to advise Congress to expand the Food and Drug Administration's "authority and resources to require manufacturers to disclose adverse events, ensure quality production and facilitate" consumers' reporting of adverse events. One suggestion: include information, including a toll-free telephone number to the FDA's Medwatch center, on dietary supplement labels.
So what's the bottom line?
Healthy eating. Food remains the best source of essential vitamins and minerals. Plus, scientists have found that something called food synergy--interaction that occurs between nutrients in food--that has yet to be duplicated by simply taking multivitamins. This may in part be due to the fact that food has lots of other nutrients that are still being identified and whose purpose is not yet known.
"I've always told my patients that [multivitamin] pills are not a substitute for food and healthy lifestyles," said Boston ophthalmologist Johanna Seddon, a co-author of the study that showed vision health benefits of taking antioxidants. "That hasn't changed." ·
Join Sally Squires, author of the newly published "Secrets of the Lean Plate Club" (St. Martin's Press), today online at www.washingtonpost.com/leanplateclub, where you can also subscribe to the free, weekly Lean Plate Club e-mail newsletter.