Vitamins: Science doesn't always match policy

Some one hundred years after the first vitamin was named, what is known about them has not translated into beneficial, standardized recommendations for public health, says Irwin Rosenberg, MD, University Professor, and director of the Nutrition and Neurocognition Laboratory at the Jean Mayer USDA Human Nutrition Research on Aging (USDA HNRCA) at Tufts University. Based on his presentation at the National Institutes of Health State-of-the- Science Conference "Multivitamin/Mineral Supplements and Chronic Disease Prevention" in 2006, Rosenberg outlines challenges and opportunities to advancing the scientific knowledge of vitamins and minerals in an article published in a January supplement of the American Journal of Clinical Nutrition.

"The evidence regarding vitamin use for prevention of chronic disease is still quite rudimentary, especially for multivitamins," says Rosenberg. Furthermore, Rosenberg points to research indicating that people who use multivitamins usually have better diets and participate in more physical activity. "Since multivitamin-users are generally healthier, it might not be feasible to attribute health outcomes to vitamin use until we have more information. The best source of vitamins is food," he adds.

To close the gap between the paucity of established scientific evidence and the widespread use of vitamin supplements, Rosenberg suggests that supplements be regulated, as they are currently subject to very little federal regulation. "Right now, the term multivitamin encompasses hundreds, if not thousands, of products with varied content and dose of vitamins and minerals. It's really difficult to guide customers if we don't even know what is in the vitamins they are taking. Standards would be helpful to both consumers and industry by rewarding those companies that do science-based marketing, rather than those that make unjustified health claims."

"In particular, issues needing more attention include the content and labeling of vitamin and mineral supplements and the effects of these products on nutrient adequacy as well as in chronic degenerative disease prevention. In this quest, the development of more and better surrogate markers of adverse effects will be critical. Dose-response assessments of safety are badly needed for updating recommended safe and tolerable Upper Intake Levels," he says.

Rosenberg also endorses a suggestion that multivitamins should be composed of clusters of vitamins and minerals that are presently supported by research to benefit public health. "We really need to encourage good study design and to establish indicators of efficacy and safety in vitamin research," he concludes. "At best, the research needed to translate scientific knowledge into policy will require a robust interaction between the public and private sectors in a regulatory framework that supports and rewards investment in good science."

Source : Tufts University