Dietary supplement is any product taken in addition to a normal balanced diet that is not a food or a drug. Dietary supplements include vitamins, minerals, amino acids, herbal preparations, and other substances derived from plants. Millions of people take dietary supplements to help ensure adequate nutrition, increase energy, reduce stress, or relieve some condition. They often regard the supplements as “natural” substitutes for drugs. Dietary supplements are sold as pills, capsules, liquids, extracts, teas, and powders. Many supplements are based on traditional folk or herbal remedies.
Many kinds of supplements, such as vitamins, provide substances that are necessary to maintain good health. Most people, however, get enough of these substances in a balanced diet. Other dietary supplements contain naturally occurring compounds that can act like drugs. In the United States, drugs must be approved by the Food and Drug Administration (FDA) before they can be sold. The FDA ensures that drugs are safe and are effective to treat the conditions for which they are prescribed. Dietary supplements can be sold without FDA approval, and thus may not be safe or effective.
Most dietary supplements are safe when taken according to directions, but some can be dangerous. Ephedra, also called ma huang, an herb taken to help people increase energy, contains the natural chemical ephedrine. Ephedrine is a stimulant that is also an ingredient in several drugs. It may cause serious side effects, including irregular heartbeat, seizures, stroke, and even death. In 2004, the FDA banned all products containing the herb. The ban was removed in 2005, however, when a federal court ruled the FDA did not have the authority to ban ephedra as a dietary supplement.
Dietary supplements can also cause harmful reactions by interacting chemically with prescription drugs. Responsible manufacturers have added labels to their products warning people not to take a supplement if they are taking certain medications. People should consult a physician before taking any dietary supplement.
Scientists are studying many kinds of dietary supplements to determine if they are effective in treating diseases. One supplement under study is made from the leaves of the ginkgo tree, which have been used as medicine for hundreds of years in China. Researchers have found that ginkgo extract may help improve short-term memory and concentration in people with Alzheimer’s disease. The FDA, however, forbids manufacturers from claiming that any dietary supplement can treat, cure, or prevent disease.