A dietary supplement, also known as a food supplement or nutritional supplement, contains a “dietary ingredient” intended to supplement the diet by providing an element that might not otherwise be consumed. “Dietary ingredients” include vitamins, minerals, herbs and other botanicals, amino acids, and substances such as enzymes, organ tissues, and metabolites. Dietary supplements, which may be extracts or concentrates, come in many forms, including tablets, capsules, soft gels, gelcaps, liquids, powders, and bars.
In some countries, dietary supplements are considered to be drugs. In the US, they are considered foods. The US Food and Drug Administration (FDA) oversees dietary supplements and mandates what must be on their labels. Manufacturers must include a descriptive name of the product, stating that it is a “supplement”; the name and place of business of the manufacturer, packer, or distributor; a complete list of ingredients; and the net contents of the product. In addition, most dietary supplements are required to have a “Supplement Facts” panel that identifies each dietary ingredient contained in the product. (Producers that make only a small amount of product and small businesses with fewer than 500 employees may apply for a waiver of this requirement.)
“Other ingredients” must also be listed; for example, rose hips as a source of vitamin C, ingredients like water and sugar, and additives required for processing, such as gelatin, colorants, preservatives, and flavors.
Dietary supplements are not intended to treat or cure illness. A supplement won’t prevent a disease the way a vaccine can. However, certain supplements decrease the risk of some conditions and can say so on their label. For instance, folic acid supplements may make a claim about reducing the risk of birth defects of the brain and spinal cord.
Before taking a dietary supplement, you should talk to a healthcare professional. Some supplements contain ingredients that have strong biological effects and may not be safe for everyone. Using supplements improperly can be harmful. Taking a supplement “combo,” taking a supplement along with medicine, or substituting a supplement for a prescribed medicine can be dangerous and even life-threatening.
Some supplements may be dangerous if taken before, during, or after surgery. For example, bleeding is a potential side effect of garlic, ginkgo biloba, ginseng, and vitamin E. Kava and valerian act as sedatives and can increase the effects of anesthetics and other medications used during surgery. Before surgery, tell your healthcare professional about every single supplement that you use.
Some supplements have been recalled because they have or may have harmful side effects. Recalls have been made for supplements that contain microbiological, pesticide, and heavy metal contamination; ingredients other than those claimed to be in the product; or more or less of the dietary ingredient than claimed on the label.
Talk with your healthcare professional to be sure your information about your supplements is reliable. Some supplement ingredients can be harmful if you take a lot of the product, take it for a long period, or take it with certain drugs or foods. Don’t substitute a supplement for medicine prescribed by your healthcare professional. Never assume that because a product is labeled “natural,” it is safe. If a product sounds too good to be true, it probably is.
If you take a dietary supplement and don’t feel well afterward, get in touch with your doctor right away. Both you and your doctor are urged to report any problems to the FDA by going to ConsumerInfo@fda.hhs.gov or by calling the FDA at 1-800-FDA-1088.