The Dietary Supplement Health and Education Act (DSHEA) of 1994 defined “dietary supplement” (to include vitamins, minerals, botanicals and other ingredients) and ruled that supplements would be regulated like foods. This exempted companies from having to prove the safety or efficacy of their products—entirely reasonable, given that the nutrients comprise natural foods, say advocates. The law also permitted supplement makers to use several kinds of marketing claims (some that don’t require FDA approval), including structure/function statements, which describe how a nutrient is intended to affect the body. (This opened doors for food producers to do the same.)
Allowing such claims—without requiring proof of strong science to back them—is why there’s so little conclusive science on supplements, say the law’s critics. “The marketing has been quite effective without studies,” says Irwin Rosenberg, M.D., senior scientist and director at the Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University. “So there’s no reason for supplement makers to do them.” Even some in the supplement industry warn that lax marketing can be misleading. “There are a few real egregious folks who go over the line with loose structure/function claims,” says Andrew Shao, Ph.D., senior vice president for scientific and regulatory affairs for the Council for Responsible Nutrition, a trade-based association that represents supplement manufacturers and suppliers. “Unfortunately consumers get the message, ‘all supplement makers are out to dupe me.’” What do the claims really mean? The answers may surprise you.