Once we believed it was possible to compensate for dietary deficiencies by popping a multivitamin every day. But research suggests that multivitamins may not be all they’re cracked up to be.
Moreover, many multivitamins contain some micronutrients in amounts greater than those recommended in the government’s Dietary Guidelines for Americans. If you choose to take a multivitamin, take one daily—no more. It’s an especially bad idea to take extra multivitamins in an effort to ramp up your intake of a single micronutrient. Doing so means you’re sure to get too much of other vitamins and/or minerals, which can be harmful.
Meanwhile, the benefits of multivitamins remain uncertain. The Women’s Health Initiative study concluded that postmenopausal women who took multivitamins did not have a lower death rate than others and were just as likely to develop cardiovascular disease or cancers of the lung, colon and rectum, breast, and endometrium. These results are consistent with findings from other studies. And in 2006, the NIH said there wasn’t enough evidence for a recommendation about taking multivitamins.
Little or no evidence of protection
There’s also been little or no evidence of protection against cardiovascular disease or cancers from a number of individual vitamin supplements, including vitamin E, vitamin C, beta carotene, and the B vitamin trio — B6, B12 , and folic acid. Recent research suggests that potential harm has been added to the mix. In 2008, a Cochrane Collaboration review found that low-risk people in trials for a host of diseases who were given supplements of vitamin A, vitamin E, and beta carotene had a slightly higher death rate. And there’s some evidence that excess folic acid (the synthetic version of folate, a vitamin found abundantly in vegetables, fruits, and grains) may be contributing to an uptick in colon polyps. Both observations warrant further study.
Experts agree that the best way to get the nutrients we need is through food (see list of nutrient-dense foods below). It is likely that what counts is the synergistic interactions of these nutrients — which might also help explain why trials of single nutrients often don’t pan out.
However, it may be too soon to draw the line on all supplements. Adequate calcium and vitamin D are essential in preserving bone density. Although you may be getting the recommended 1,200-mg calcium requirement in your diet, it may be almost impossible to get the recommended 1,000 mg of vitamin D, which is essential for calcium absorption, through food intake and sun exposure.