A statement from the Harvard School of Public Health says, "There's good evidence that taking a daily multivitamin makes sense for most adults." It names five vitamins - folic acid and vitamins B6, B12, D, and E - as especially important for the prevention of several chronic diseases.
I certainly agree with the choice of vitamin D, but not with the statement that good evidence supports taking the others. Folic acid and vitamins B6 and B12 are recommended to reduce the risk of cardiovascular disease by lowering blood levels of homocysteine. But three large, randomized, controlled studies showed no reduction in cardiovascular disease in people taking this combination of supplements for as long as five years.
Vitamin E is recommended as an antioxidant to prevent coronary heart disease events, but several large studies have shown no protection from vitamin E against cardiovascular disease events, and one analysis found that large doses of vitamin E may even be harmful.
As with any and all marketing of products, my advice is "let the buyer beware." Some manufacturers try to lure buyers by selling vitamin concoctions aimed specifically at women or at people of different ages. Others add unproven non-vitamin supplements like lutein, lycopene, choline, or inositol.
Most multivitamins are undoubtedly safe, but some may not be. For example, one label I ran across tells people to take two pills daily of a multivitamin containing 800 IU of vitamin D - but 1600 IU of vitamin D can be a toxic dose!
Despite the ads, vitamins will not increase your strength or energy, yet we all know about the many professional athletes who take vitamins and other supplements by the handful.
It's not surprising that representatives of the dietary supplement industry, as well as others whose main business is to sell vitamins and supplements, criticized the conclusions of a National Institutes of Health panel whose members felt the evidence did not justify a recommendation that people take a daily multivitamin.
Critics complained that the panel relied only on data from randomized controlled trials and ignored the findings from many small observational studies which have shown benefits from taking vitamins.
Panel members responded - appropriately, I believe - that these uncontrolled studies are not reliable partly because people who take vitamins generally take better care of their health than most other Americans.
The bottom line is that there is simply not enough information from the few controlled studies on the benefits and safety of multivitamins, and the panel cited the need for more of these studies.
If you are among the half of American adults who spend an estimated $7 billion annually on multivitamins, you can at least save some money by buying the least expensive multivitamin you can find.
In a future entry, I'll tell you about who really needs to take some of the few vitamins with proven benefits.
