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. As defined in the Dietary Supplement Health and Education Act, which became law in 1994, a dietary supplement is a 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 are these supplements helpful, harmful or worthless? EN explores the myths.
Myth 1: Supplements Are Proven to Be Safe. A 2015 Consumer Reports survey found that most people think that dietary supplements are vetted for safety by the U.S. Food and Drug Administration (FDA). Not true. Unlike prescription or 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: 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 (USP), 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. Duffy MacKay, ND, vice president of regulatory affairs for the Council for Responsible Nutrition, a supplement trade organization, points out that some major brands don’t use third-party testing because they have strong internal standards. “They’re using their brand as their seal.”
Myth 3: The Information on the Label 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, 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, but this is difficult to monitor.
Myth 4: Herbal Supplements Are Natural, So They’re Safe. The safety of an herb or botanical depends on many things, such as its form, dose, and how it works in the body, according to the Office of Dietary Supplements (ODS), part of the National Institutes of Health. The effects of herbal products range from mild to powerful, and many herbal products can interact with prescription drugs, either increasing or decreasing the potency of the drug.
Myth 5: Weight Loss Supplements are Safe and Effective. The FDA has identified weight loss supplements as a category of concern because they may contain ingredients that are harmful in high doses. A 2015 study led by the FDA and the Centers for Disease Control and Prevention found that among adults 25 percent of emergency room visits for adverse effects from dietary supplements were due to weight loss supplements, with cardiac symptoms being the primary complaint. MacKay says, “When you start talking about quick fixes and miracles cures, we just haven’t discovered those things yet.”
Myth 6: It’s Good “Insurance” to Take a Multi. There’s no evidence supporting use of multivitamins for people who are eating a healthy diet, but the ODS suggests that people who don’t get enough vitamins and minerals from food alone because they are on a low-calorie diet, have a poor appetite, or avoid certain food groups might consider taking a multivitamin/mineral.
Myth 7: Supplements Just Produce “Expensive Urine.” “It’s really alarming to lump all dietary supplements together and call them useless,” MacKay says, pointing out that the U.S. Dietary Guidelines for Americans has noted serious shortfalls in calcium, vitamin D, fiber and potassium, and that evidence supports the value of prenatal vitamins and supplementation of specific nutrients for individuals who don’t absorb them well.
Myth 8: It Doesn’t Matter When You Take Supplements. If the label recommends taking at a certain time of day, follow those instructions. Otherwise, it’s generally best to take them during or right after a meal containing fat to promote absorption and reduce the risk of stomach irritation. This is particularly important for the fat-soluble vitamins (A, D, E and K). Some supplements can interact with prescription medications, so you may need to take them separately.
Myth 9: “Whole Food” Supplements are Best. According to ConsumerLab, there’s no clear benefit to using supplements made from whole foods. Their website states, “When it comes to natural vs. synthetic forms of vitamins in dietary supplements, sometimes natural is better, sometimes synthetic is better, and sometimes it doesn’t matter.” They point out that all vitamin supplements can help prevent or treat deficiencies, and nearly all can be harmful at too high a dose.
—Carrie Dennett, MPH, RDN