Can taking dietary supplements improve my health?

Probably not. Although manufacturers of dietary supplements market their products as an easy way to get and stay healthy, there is little clinical research that supports these statements.

Note: Two important exceptions are calcium and Vitamin D, which can be effective in helping some people meet their daily intake needs.

Are dietary supplements safe?

Despite the fact that there are hundreds of dietary supplements that promise everything from improved memory to weight loss to staving off the common cold, dietary supplements are not regulated or reviewed by the FDA before they are made available to the public.

Although lack of FDA approval does not necessarily mean that supplements are unsafe, studies have shown that some dietary supplements do not contain the advertised ingredients or contain other, unlisted ingredients—increasing the risk of unintended side effects such as allergic reactions. Research has also shown that dietary supplements can be harmful in high doses and can interact dangerously with other medications.

Are there any supplements that have been studied?

Yes. Several supplements have been studied or are being studied now, including:

• Calcium. Although high doses of calcium from supplements do not have much effect on bone density, calcium supplements can be used to help you meet your daily intake needs, up to 600 mg per day. High doses of calcium can increase your risk of heart disease and kidney stones.
• Vitamin C. There is very little proof that Vitamin C has any effect on the common cold.
• Melatonin. Melatonin is a synthetic copy of a natural hormone that is used to treat jet lag and sleep problems such as insomnia. Studies show that it can be effective at doses as low as 0.5 mg, but you should talk to your doctor about the right dosage and timing for you.
• Vitamin D. Vitamin D supplements can be used to help nutrient-deficient people meet their recommended daily intake. The 25,000-person VITAL study is currently being conducted to determine if high doses of Vitamin D can reduce the risk of heart attack, stroke or cancer. Results of the study are expected in 2017.
• Omega-3 fatty acids. Studies have shown that consuming foods high in omega-3s reduced risks of heart disease and inflammation. However, it is unclear if omega-3 supplements such as fish oil have the same effect. The VITAL study is currently exploring this question.

Are there any herbal remedies that have been studied?

Yes. Several herbal remedies have been studied, including:

• Chamomile. Although less potent than prescription drugs, this herb appears to help relieve anxiety. Because it is related to ragweed, marigolds, chrysanthemums and daisies, it may trigger allergies in some people.
• Echinacea. There is no evidence that echinacea either prevents colds or reduces cold symptoms. Like chamomile, it may trigger allergies in people allergic to ragweed, marigolds, chrysanthemums and daisies.
• Ginseng. There is no evidence that ginseng is a remedy for colds, fatigue or forgetfulness. It can interact with aspirin and the anti-clotting drug warfarin (Coumadin).
• Ginkgo biloba. In a study of 3,000 men and women older than age 75, there was no evidence that ginkgo biloba slowed cognitive decline or reduced the incidence of dementia during a six-year period. Ginkgo biloba can increase the risk of bleeding.
• St. John’s wort. Although a few early studies showed that St. John’s wort might alleviate depression, larger trials failed to confirm those results. St. John’s wort interacts with a large number of prescription medications.

If you are thinking about taking a dietary supplement, you should talk to your doctor about the potential benefits, risks, side effects and recommended dosage for you.