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Jennifer Grebow is editor-in-chief of Nutritional Outlook.
The multivitamin is still working to win the endorsement of U.S. scientific bodies. Why?
The multivitamin stands at a crossroads. Beloved by many, it still ranks most popular among U.S. supplements; yet, it is still working to win the endorsement of U.S. scientific bodies.
More than half of American adults take multivitamins, according to the Council for Responsible Nutrition’s (CRN; Washington, DC) annual Consumer Survey on Dietary Supplements. America’s vote of confidence, though, is not mirrored in the opinions of those who set healthcare recommendations, such as the U.S. Preventive Services Task Force (USPSTF). This past February, in its official recommendation statement on the use of vitamins, minerals, and multivitamin supplements for the primary prevention of cardiovascular disease and cancer, USPSTF concluded that “current evidence is insufficient to assess the balance of benefits and harms of the use of multivitamins for the prevention of cardiovascular disease or cancer.” Take, also, researchers’ conclusions in the Physicians’ Health Study II (PHS-II), a large-scale, randomized, double-blind, placebo-controlled trial in predominantly older, white, male physicians to study the long-term effects of a multivitamin on chronic disease. In 2012, PHS-II researchers stated that “taking a daily multivitamin did not reduce major cardiovascular events” in the study population; in 2013, reporting on the cognitive arm of that same trial, the researchers concluded that cognitive decline was actually worse in the multivitamin group. (There were some positive takeaways, however, including benefits for the reduced risk of cancer and cataracts.)
These reports are weighty, given that the U.S. Department of Health and Human Services and the USDA are gearing up to release the 2015 Dietary Guidelines for Americans (DGFA; updated every five years). In 2010, the DGFA’s official stance on multivitamins was very much like that of the USPSTF’s: “Sufficient evidence is not available to support a recommendation for or against the use of multivitamin/mineral supplements in the primary prevention of chronic disease for the healthy American population.”
Industry groups like CRN are working to frame the multivitamin message appropriately, as the supplements industry has always advocated: for filling nutrient gaps and shoring up general good health. As Duffy MacKay, ND, CRN’s senior vice president of scientific and regulatory affairs, said in response to the PHS-II study, “no one should expect the multivitamin to wipe out all diseases known to man.”
With this in mind, CRN’s comments this September to the Dietary Guidelines Advisory Committee (DGAC) encouraged the committee to recommend multivitamins as a “no-calorie, low-cost, convenient way to fill…nutrient gaps when nutrient recommended intakes are not first met through the consumption of food.” As the association wrote, “It is important to underscore that a [multivitamin] is not meant as a replacement for a healthy diet, but as a supplement to a healthy diet that can help to achieve adequate nutrient intake.”
Neither USPSTF nor the DGAC necessarily believes multivitamins are worthless. The 2010 DGFA point out that supplements may indeed benefit nutrient-deficient populations, such as those low in vitamin D, folic acid, and vitamin B12. But these scientific bodies would like to see more definitive research on multivitamins. The supplements industry would like to see this, too. After all, as CRN’s MacKay reminded following the USPSTF’s recommendation, “there is a big difference between lack of research and lack of positive results.” More studies, for instance, are needed in subjects representative of the general population. The USPSTF said there is currently “a critical gap in the evidence…[in] studies of multivitamin combinations in groups generalizable to the U.S population.”
USPSTF also noted, however, that “There are substantial challenges to studying nutrient supplementation by using methods similar to those used in studying pharmaceutical interventions. New and innovative research methods for examining effects of nutrients that account for the unique complexities of nutritional research but maintain rigorous designs should be explored.”
And this is what the supplements industry has been saying all along. “CRN and others in the academic community have made some headway in differentiating evidence-based nutrition, and the need to look beyond drug-like RCTs when considering scientific standards for nutrients, but there’s still more to be done, particularly among scientists whose expertise is in conventional medical research,” says Judy Blatman, CRN’s senior vice president, communications.
“However," she adds, "even as we try to change that mindset, we should still be supporting more well-designed research on the multivitamin.”
Until definitive data indicates otherwise, neither scientific bodies nor media nor consumers should write off the multivitamin just yet-far from it. “We’re hopeful that the [Dietary Guidelines Advisory] Committee will expand its view of what constitutes nutrition, and focus on getting nutrients not only through conventional foods, but considering other delivery methods as well,” Blatman says.
Read my full interview with Judy Blatman on what’s happening with the multivitamin here.
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