dietary supplement

:  a product taken orally that contains one or more ingredients (such as vitamins, minerals, herbs, or amino acids) that are intended to supplement one's diet and are not considered food The study is looking at whether taking daily dietary supplements of vitamin D₃ or omega-3 fatty acids reduces the risk for developing cancer, heart disease and stroke.—Mary Brophy Marcus, USA Today, 4 Oct. 2011 A hormone produced by the pineal gland in the brain, melatonin also occurs naturally in some foods. It therefore may be sold as a dietary supplement in the United States under the Dietary Supplement Health and Education Act of 1994, without premarket approval from the FDA.—Lynne Lamberg, The Journal of the American Medical Association, 2 Oct. 1996 … batches of a dietary supplement L-tryptophan that have been implicated in a mysterious disease were produced by a genetically engineered organism.—Leslie Roberts, Science, 31 Aug. 1990