From Cathy Wong,
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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 about supplements and claims of benefits for health. 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? This fact sheet provides some answers.

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 2002.3 In it, over 2,500 Americans reported on supplements they used (given the categories of vitamins/minerals and herbal products/natural supplements) and for what reasons. Their responses are summarized below:

Vitamins/Minerals

• 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%
  

Herbals/Supplements

• 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%
  

* Adapted from Kaufman DW, Kelly JP, Rosenberg L, et al. Recent patterns of medication use in the ambulatory adult population of the United States: the Slone survey. Journal of the American Medical Association. 2002;287(3):337-344. Copyright © 2002, American Medical Association. All rights reserved.

How can I get science-based information on a supplement?

There are several ways to get information on supplements that is 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 can access the latest medical guidance about its uses and risks.

You can find out yourself whether there are any scientific research findings on the CAM supplement you are interested in. NCCAM and other Federal agencies have free publications, clearinghouses, and databases with this information.

If I am interested in using a supplement as CAM, how can I do so most safely?

Here are some points to keep in mind:
1. It is important to talk to your health care provider (or providers, if you have more than one) about the supplement. This is for your safety and a complete treatment plan. It is especially important to talk to your provider if you:

• Are thinking about replacing your regular medical care with one or more supplements.
  
• Are taking any medications (whether prescription or over-the-counter). Some supplements have been found to interact with medications (see box below).
  
• Have a chronic medical condition.
  
• Are planning to have surgery. Certain supplements may increase the risk of bleeding or affect anesthetics and painkillers.
  
• Are pregnant or nursing a baby.
  
• Are thinking about giving a child a supplement. Many products being marketed for children have not been tested for their safety and effectiveness in children.
  

2. Do not take a higher dose of a supplement than what is listed on the label, unless your health care provider advises you to do so.

3. If you experience any side effects that concern you, stop taking the supplement, and contact your provider. You can also report your experience to the U.S. Food and Drug Administration's (FDA) MedWatch program, which tracks consumer safety reports on supplements.

4. If you are considering or using herbal supplements, there are some special safety issues to consider.

5. For current information from the Federal Government on the safety of particular supplements, check the "Alerts and Advisories" section of the NCCAM Web site or the FDA Web site.

Supplements and Drugs Can Interact

For example:

• St. John's wort can increase the effects of prescription drugs used to treat depression. It can also interfere with drugs used to treat HIV infection, to treat cancer, for birth control, or to prevent the body from rejecting transplanted organs.