Updated: Jan 8
Dietary supplements are a topic of great public interest. Whether you are in a store, using the Internet, or talking to people you know, you may hear claims about their health benefits. How do you find out whether "what's in the bottle" is safe to take and whether science has proven that the product does what it claims?
What Are Dietary Supplements?
Dietary supplements (also called nutritional supplements, or supplements for short) are defined by the following criteria:
Are taken by mouth.
Contain a "dietary ingredient" intended to supplement the diet. Examples of dietary ingredients include vitamins, minerals, herbs (as single herbs or mixtures), other botanicals, amino acids, and dietary substances such as enzymes and glandulars.
Come in different forms, such as tablets, capsules, softgels, gelcaps, liquids, and powders.
Are not represented for use as a conventional food or as a sole item of a meal or the diet.
Are labeled as being a dietary supplement.
Dietary supplements are sold in grocery, health food, drug, and discount stores, as well as through mail-order catalogs, TV programs, the Internet, and direct sales.
Why Do People Take Supplements?
People take supplements for many reasons. A scientific study on this topic was published in 2002. Over 2,500 Americans reported on supplements they used (given the categories of vitamins/minerals and herbal products/natural supplements) and the reasons for taking them. Their responses are summarized below:1
Health/good for you - 35%
Dietary supplement - 11%
Vitamin/mineral supplement - 8%
Prevent osteoporosis - 6%
Physician recommended - 6%
Prevent colds/influenza - 3%
Don't know/no reason specified - 3%
Immune booster - 2%
Recommended by friend/family/media - 2%
Energy - 2%
All others - 22%
Health/good for you - 16%
Arthritis - 7%
Memory improvement - 6%
Energy - 5%
Immune booster - 5%
Joint - 4%
Supplement diet - 4%
Sleep aid - 3%
Prostate - 3%
Don't know/no reason specified - 2%
All others - 45%
How Can I Get Science-Based Information on a Supplement?
There are several ways to get information on supplements that are based on the results of rigorous scientific testing, rather than on testimonials and other unscientific information.
Ask your health care provider. Even if your provider does not happen to know about a particular supplement, he or she may have professional resources to turn to about uses, potential risks, and drug interactions.