On Nutrition

The dietary supplement industry brings in billions of dollars each year, with an estimated 90,000 products on the market — in a range that extends far beyond multivitamins.

A dietary supplement is any product that’s intended to supplement the diet with one or more dietary ingredients. This includes vitamins, minerals, herbs or other botanicals, amino acids, or other substances in pill, capsule, tablet or liquid form. But not all dietary supplements are as beneficial as they appear. Here’s what you need to know before you open your wallet.

Myth 1: Supplements are proven to be safe.

Yes or no: dietary supplements are vetted for safety by the U.S. Food and Drug Administration. The answer is “no.” Unlike prescription and over-the-counter drugs, which must be approved by the FDA before they can be marketed, the FDA is not authorized to review dietary supplements for safety and effectiveness before they are marketed. The FDA can take action if they receive reports that a supplement already on the market is causing harm, but this can take several years.

Myth 2: The label information is science-based.

Dietary supplement labels can claim that the product addresses a nutrient deficiency, supports health or is linked to a particular body function (like immunity, bone health, heart health or cognitive function). The claim may not necessarily be backed up by scientific evidence. Product labels containing health claims must also include a disclaimer that reads, “This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure or prevent any disease.” The FDA and the Federal Trade Commission can take action if a product on the market has false or misleading claims, but this is difficult to monitor.

Myth 3: Herbal supplements are safe, because they’re natural.

According to the Office of Dietary Supplements, part of the National Institutes of Health, the safety of an herb or botanical depends on many things, such as its form, dose and how it works in the body. The effects range from mild to powerful, and many herbal products can interact with prescription drugs, either increasing or decreasing the potency of the drug.

Myth 4: “Whole food” supplements are best.

According to ConsumerLab, there’s no clear benefit to using supplements made from whole foods. “When it comes to natural versus synthetic forms of vitamins in dietary supplements, sometimes natural is better, sometimes synthetic is better and sometimes it doesn’t matter.” The bottom line is that all vitamin supplements can help prevent or treat deficiencies, and nearly all can be harmful at too high a dose.

Myth 5: A “stamp” on the label assures quality.

Many supplement bottles have stamps all over them, but some stamps mean more than others. Several independent organizations — notably U.S. Pharmacopeia, ConsumerLab and NSF International — offer quality testing. Their seals of approval mean that the supplement was properly manufactured, contains the ingredients listed on the label and doesn’t contain harmful levels of contaminants. They don’t guarantee that a product is safe or effective.