Responding to the Negative NIH Report About Dietary Supplements

The National Institutes of Health (NIH) in mid-May announced certain conclusions reached during a panel from the State of Science Conference on Multivitamin and Mineral Supplements. Some of the conclusions appeared well-founded, while others were just confounding.

One of the easiest to agree with was their statement that more than half of American adults are taking dietary supplements, the majority of which are multivitamin and mineral supplements. According to the most recent National Health and Nutrition Examination Survey (NHANES) data more than half (52 percent) of American adults use some sort of dietary supplement. The number is higher for women than for men and varies by age group, with a 63-percent use rate among adults ages 60 and up. Other surveys have shown higher supplement usage amongst adults, with a Council for Responsible Nutrition (CRN) survey finding 62 percent of American adults take supplements.

However, the panel didn’t know for sure whether Americans were benefiting from the supplements. This was an odd conclusion since there is a preponderance of evidence demonstrating benefits from the use of supplements. In general, multivitamin users tend to adopt other healthy habits and to have a reduced risk of some chronic diseases.

Multivitamins help fill nutrition gaps and ensure adequate intake of a variety of nutrients, as well as help in promoting overall good health. The use of a daily multivitamin can help maintain proper immune function, and is particularly important in older Americans and may protect against infectious disease and cognitive decline. Additional benefits include:

• Antioxidant vitamins and minerals can support eyesight, help maintain cognitive function, combat oxidative damage from environmental exposures and potentially reduce the risk of some chronic diseases, including some cancers and heart disease. The panel did advocate that antioxidants and zinc be considered for use by nonsmoking adults with intermediate-stage, age-related macular degeneration, an eye condition that can cause blindness.
• Folic acid plays a critical role in protecting against neural tube birth defects such as spina bifida when taken by women of childbearing age before and during pregnancy. Again, the panel did support previous recommendations that women of childbearing age take daily folate to prevent neural tube defects.
• A calcium supplement with vitamin D can help to achieve peak bone mass, slow the rate of bone loss that occurs with aging and protect against the development of osteoporosis. The panel did recommend the combined use of calcium and vitamin D supplementation for postmenopausal women to protect bone health.

The panel was also concerned that some people may be getting too much of certain nutrients, with the resulting increased possibility of adverse effects. This is another odd conclusion, considering that nutrition surveys consistently show a substantial proportion of the American public fails to consume the Recommended Dietary Allowances (RDA) of various nutrients.

According to the 2005 Dietary Guidelines for Americans, the vitamins and minerals that are in especially low amounts in American diets include vitamins A, C and E, and calcium and magnesium. A 2002 article in The Journal of the American Medical Association (287:3127-29) stated: “Most people do not consume an optimal amount of all vitamins by diet alone. Pending strong evidence of effectiveness from randomized trials, it appears prudent for all adults to take vitamin supplements.”

Furthermore, the evidence overwhelmingly supports healthful benefits of vitamins. In general, for the healthy population, taking vitamin supplements in reasonable amounts is safe. The National Nutritional Foods Association (NNFA) made a good point in a press release it issued after NIH released its findings: “NNFA maintains that multivitamins do not pose a health risk as the panel theorizes and asserts that serious adverse health reactions would have long since been apparent. As an example, according to the most recent data from the American Association of Poison Control Centers, adverse reactions to all vitamins represented only 4 percent of the category that includes prescription and over the counter (OTC) drugs.”

The panel found insufficient data available to make a firm recommendation for or against the use of multivitamin and mineral supplements in the general population for the purpose of chronic disease prevention. Apparently the panel must not have reviewed the same data JAMA examined. In fact, the JAMA authors added: “Vitamin deficiency syndromes such as scurvy and beri beri are uncommon in Western societies. However, suboptimal intake of some vitamins, above levels causing classic vitamin deficiency, is a risk factor for chronic diseases and common in the general population, especially the elderly.” Apparently, the suboptimal intake of nutrients was significant enough to lead the AMA to the conclusion that supplementation is recommended for the general population.

Interestingly, the panel advocated that Congress expand the Food and Drug Administration’s (FDA) authority regarding the regulation of dietary supplements. NNFA gave an appropriate response: “The panel’s claim that FDA doesn’t have enough regulatory authority is irresponsible. While it certainly may be true that the agency that regulates dietary supplements is both underfunded and understaffed, it is not powerless to enforce the law. Among the powers granted by the Dietary Supplement Health and Education Act of 1994 (DSHEA), FDA has the authority to seize products determined to present an unreasonable or significant risk of injury or illness or an imminent hazard to the public health. Additionally, DSHEA authorized FDA to establish good manufacturing practices (GMPs) for dietary supplements.”

When used responsibly, dietary supplements are safe, effective and may play a valuable role in helping to prevent certain diseases. Don’t stop taking your supplements because of the new NIH report. I know I won’t.

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