By Brierley Wright, M.S., R.D., Nutrition Editor, EatingWell Magazine
A recent government study said more than half of all Americans take dietary supplements, which in my opinion is surprisingly high, considering these pills and powders arenât regulated like drugs but like foods.
The Dietary Supplement Health and Education Act (DSHEA) of 1994 defined âdietary supplementâ 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 come from natural foods, say advocates. The law also permitted supplement makers to use several kinds of marketing claims (some that donât require FDA approval), including structure/function statements, which describe how a nutrient is intended to affect the body.
Allowing such claims -- without requiring proof of strong science to back them -- is why thereâs so little conclusive science on supplements, say the lawâs critics. âThe marketing has been quite effective without studies,â says Irwin Rosenberg, M.D., senior scientist and interim director of the Neuroscience and Aging Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. Even some in the supplement industry warn that lax marketing can be misleading. âThere are a few real egregious folks who go over the line with loose structure/function claims,â says Andrew Shao, Ph.D., Vice President, Global Product Science & Safety at Herbalife. âUnfortunately consumers get the message, âall supplement makers are out to dupe me.ââ What do the claims really mean? The answers may surprise you. Here are 5 myths about vitamins busted, originally reported on in EatingWell Magazine by Nicci Micco.
Myth 1: All âMultivitaminsâ Are the Same
The Truth: Thereâs no legal definition for âmultivitamin.â Manufacturers apply the term to any product supplying two or more vitamins (minerals, phytochemicals and herbs too). In a 2006 study of 26,735 people out of the University of Hawaii in Honolulu, the âmultivitaminsâ subjects reported using included 1,246 different formulas. Nearly 70 percent were âone-a-dayâ types; 16 percent, B-complex blends; and 14 percent, âantioxidantâ mixes. Products in the same group (e.g., B-complex) varied wildly; many provided megadoses of some nutrients.
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The Bottom Line: Read labels to find a âmultiâ that doesnât exceed 100 percent of the Daily Value (DV) for any nutrients.
Myth 2: Whatâs Listed on the Label Is Whatâs Really in the Product
The Truth: Supplement manufacturers must list each ingredient (and its quantity) in a product, but they donât have to prove the accuracy of these lists. Limited in resources, the FDA doesnât check that whatâs inside a product jibes with whatâs on its label, either. Often labels donât match contents: 30 percent of âmultivitaminsâ tested by ConsumerLab.com, an independent nutrition product testing service and consumer watchdog group, were âoffâ for at least one ingredient, says Tod Cooperman, M.D., the groupâs president. Some delivered doses well below those listed on the label; one was tainted with potentially dangerous levels of lead.
Manufacturers can pay to have products tested by ConsumerLab.com or a similar independent company, U.S. Pharmacopeia (USP), usp.org, to verify that the formula: 1) is what itâs supposed to be, 2) doesnât contain contaminants, and 3) dissolves properly in the body. (Note: Such certification doesnât guarantee safety or effectiveness, just that a product is what the label says.) âPassingâ products earn the right to bear a special seal. The absence of a seal doesnât necessarily signal a bad product: Big companies often do their own quality-assurance testing.
The Bottom Line: Buy products with a certified seal -- such as the USP seal or certification from ConsumerLab.com -- or an established brand.
Myth 3: Calcium Is Calcium
The Truth: Vitamins and minerals occur in different forms -- all of which may not function equally. A 2005 study in the Journal of the American Dietetic Association showed that an orange juice fortified with calcium citrate malate was absorbed 48 percent better than one fortified with the same amount of calcium in a different form. Manufacturers donât have to prove that nutrients they add to foods are actually absorbed.
Bottom line: A dietitian can help you pick products likely to be well absorbed.
Myth 4: Structure/Function Claims Are Backed By Solid Science
The Truth: Structure/function claims (e.g., "Zinc helps maintain immunity,") describe what an ingredient is intended to do in the body. Often, the research behind the claim has no scientific consensus. (Look closely: Packages with structure/function claims must also bear the disclaimer, âThis statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.â) âClaim-featuredâ nutrients sometimes are included purely for marketing.
Example: Research on phytochemicals (such as lycopene) is still new, and their potential benefits are poorly understood. Yet âmanufacturers will throw in just a tiny bit,â says Cooperman. âIf consumers have heard of an ingredient, they assume it has some value.â âPremiumâ ingredients can mean the difference between charging $50, versus $8, for a bottle of multivitamins.
The Bottom Line: Watch out for âbuzz wordâ nutrients and claims that appear too good to be true.
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Myth 5: âStudies Have ShownâŠâ Means That Clinical Research Conclusively Showed Whatever Statement Follows
The Truth: Most studies that âshowâ a vitamin/mineral supplement provides a health benefit are observational ones, which survey people about various behaviors (e.g., diet, exercise, supplement use), then use statistical analyses to identify links with disease. When an observational research finds, âPeople who took a multivitamin, daily, for âXâ number of years have an âXâ percent lower chance of developing colon cancer than those who didnât,â one canât assume that the multivitamin (not a combination of factors) was fully responsible. Surveys show that supplement users tend to practice other healthy habits, too -- eating lots of vegetables, shunning cigarettes and exercising regularly -- so itâs hard to tease out a single protective factor.
This is why diet/disease links found in observational studies must be confirmed in controlled randomized clinical trials. In these âgold-standardâ investigations, researchers deliver specific nutrient doses to one group and placebo âsugar supplementsâ to another (neither the subjects nor the investigators know whoâs getting what) to test whether a supplement is really responsible for observed benefits.
The Bottom Line: Supplement makers donât have to say how scientifically conclusive their studies are.
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By Brierley Wright, M.S., R.D.
Brierley's interest in nutrition and food come together in her position as nutrition editor at EatingWell. Brierley holds a master's degree in Nutrition Communication from the Friedman School of Nutrition Science and Policy at Tufts University. A Registered Dietitian, she completed her undergraduate degree at the University of Vermont.
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