How are the health benefits of vitamin supplements tested?

Dwight L. McKee, MD
Hematology & Oncology
There are many different ways to study vitamin supplements, but the “gold standard” test for any medical treatment is called a randomized clinical trial. In a randomized clinical trial, researchers give a treatment to one group of people, then compare that group with another group -- known as the control group -- that does not receive the treatment. In many cases, people in the control group receive a fake pill called a placebo, or "sugar pill."

While this type of study may work for identifying safe and effective drugs, it isn't ideal for studying vitamin supplements. Vitamins aren't drugs. Unlike drugs, vitamins don't work in isolation; instead, they act together in complex networks with other vitamins, minerals, and nutrients. That means taking large doses of a single nutrient may not produce any benefits, especially if you eat a diet that's low in nutrients. This fact makes the results of some studies of vitamin supplements difficult to interpret. Doctors and scientists need to work together to find a better way to study the health benefits of nutrition supplements.
The health benefits of vitamin supplements are tested differently than the health benefits of drugs. Before a drug is available on store shelves or by prescription, the manufacturer does laboratory, animal and human testing on the medication, then submits all of the test results and other information available to an independent panel of experts at the Food and Drug Administration (FDA) for review. If the FDA decides that the drug is safe and effective, it may approve it for sale and distribution in the U.S.

In contrast, regulation of dietary supplements falls under a law passed by Congress in 1994 called the Dietary Supplement Health and Education Act. Under this law, the FDA does not review the safety, effectiveness or health claims of supplements before they are brought to market. The manufacturer is responsible for making sure that the product is safe and provides the benefits it claims to have on the label. Talk to your doctor for more information about the safety and effectiveness of dietary supplements.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.