Omega-3 fatty acids

What it does: Omega-3 fatty acids (which should not be confused with omega-6 fatty acids) are important for blood clotting, cell division and the relaxation and contraction of muscles.

Good to know: The omega-3 fatty acids plentiful in fatty fish and fish oil supplements have built a powerful reputation for reducing the risk of a second heart attack. Studies on fish oil and memory have had mixed results. Also, fatty acid supplements may interact with blood thinners.

Echinacea

What it does: This plant may reduce the duration of a cold.

Good to know: Study results are mixed about whether echinacea can prevent colds and other infections.

Gingko

What it does: Derived from the oldest living tree species, ginkgo extract improves walking in people with certain circulatory problems that affect the legs.

Good to know: Research on ginkgo's effect on Alzheimer's and memory loss has been disappointing. Ginkgo can increase bleeding risk, so talk to your doctor if you take blood thinners or have surgery scheduled.

Ginseng

What it does: The root of the ginseng plant appears to benefit people with heart disorders. It may also lower blood glucose levels in people with type 2 diabetes.

Good to know: People with diabetes should use caution with ginseng, especially if they are taking medication to lower blood glucose.

Nissa Simon, a health writer, lives in New Haven, Conn.

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