The Truth Behind the Top 10 Dietary Supplements
What you need to know about the most popular dietary and nutritional supplements on the market.
By Kathleen Zelman, MPH, RD/LD
Reviewed By Louise Chang, MD
A visit to the health food store can be an overwhelming experience. It's tough to figure out what to choose from among the dizzying assortment of dietary and nutritional supplements on the shelf. From vitamins to minerals to weight loss pills, there are thousands of options to choose from. But do you really need any of them? Do they really work, and if so, which ones are best?
WebMD turned to some experts for answers about the multibillion-dollar dietary and nutritional supplement industry.
Total sales for the U.S. dietary supplement industry in 2006 are estimated at $22.1 billion, with vitamins accounting for $7.2 billion of that, says Patrick Rea, editor of the market research publication Nutrition Business Journal. Included in this total are not only sales of vitamins, but also those of minerals, herbs/botanicals, sports supplements, meal supplements, and weight loss products.
How Are Dietary Supplements Regulated?
The Dietary Supplement Health and Education Act, approved by Congress in 1994, defines dietary supplements as products that:
The Food and Drug Administration (FDA) once regulated dietary supplements the same way it does foods, but that changed as of Aug. 24, 2007. The FDA's new good manufacturing practices ruling ensures that supplements:
"Making cereal is very different from making dietary supplements. ... This new ruling is very specific to the production of capsules and powders and will give consumers great confidence that what is on the label is indeed in the product," says Vasilios Frankos, PhD, of the FDA's Division of Dietary Supplement Programs.
The FDA provides manufacturers with guidelines for making claims about what effects their products have on the body, Frankos says.
"If they make a claim, they must notify us so we can review it," Frankos says. "Manufacturers have to provide us with evidence that their dietary supplements are effective and safe."
Who Needs Dietary Supplements?
It's important to remember that dietary supplements are designed to supplement your diet, not to replace nutritious foods.
"Supplements can enhance a diet where there are shortfalls, but a handful of vitamin, mineral or other dietary supplements can never take the place of a healthy diet," says David Grotto, RD, a spokesperson for the American Dietetic Association (ADA).
"Foods are so complex, offering not only vitamins and minerals, but fiber, nutrients (carbohydrates, proteins, and fats), phytochemicals, and a whole host of nutritious substances that science has not fully identified that work together with other foods and provide the benefits of a healthy eating pattern."
Still, the ADA recognizes that some people may require supplements because the vitamins and/or minerals they need are hard to get in adequate amounts in the diet. These groups include:
Top 10 Dietary Supplements
Whether they really need them or not, sales figures show that plenty of people are purchasing supplements. Here are the top 10 most popular supplement categories, based on sales calculated by the Nutrition Business Journal:
Dietary Supplement No. 1: Multivitamins
Multivitamins lead the pack, and with good reason. Taking a daily multivitamin with minerals has long been considered nutritional "insurance" to cover dietary shortfalls.
"There is no harm in taking a once-daily multivitamin, as long as you select one based on your age and sex," says Grotto. "Take one daily or just on days when your diet is inadequate. But better than a multivitamin is to fill in the gaps with food that offers so much more than supplements."
Dietary Supplement No. 2: Meal Replacements
Powdered and liquid products like SlimFast and Ensure might not be what most of us think of as dietary supplements. But they're included in the list because they are designed to supplement the diet.
For people who can't eat regular food because of illnesses, these products are good alternatives. Still, "eating a wide variety of nutrient-rich foods is better, if tolerated," says Grotto.