Whatever your age, the time to prevent heart disease is now, starting with eating a plant-based diet, stepping up exercise, slimming down, and not smoking. For those at high risk, or with existing heart disease, there's evidence that certain supplements may help. Before trying the ones here, talk with your doctor, especially if you're taking medication.

Omega-3 Fatty Acids
These healthy fats have emerged as the runaway heart-helpers, with numerous studies showing they can help reduce the risk of heart attack, stroke, and atherosclerosis. If you've had a heart attack, omega-3s appear to reduce the risk of suffering another one. Fish oil is by far the best supplement source of omega-3s. (If you're a vegetarian, sources such as flaxseed oil are better than nothing.) If you're concerned about mercury and PCBs in supplements, know that independent researcher consumerlab.com found no evidence of contaminants in 42 brands. Freshness is of greater concern, says Dr. David Rakel, director of the Integrative Medicine Program at the University of Wisconsin's School of Medicine and Public Health, because fish oil breaks down when exposed to light and heat. To avoid buying rancid oil, check the label for natural preservatives like vitamin E or rosemary and purchase supplements from a reputable natural-foods store with high turnover. Store fish oil in the refrigerator.
Dosage Up to 3,000 mg per day of fish oil, split among three doses (discuss with your physician); 3,000 mg flax oil.

Coenzyme Q10
Produced by the body for cell growth, this vitamin-like substance may reduce the muscle aches that plague some patients who take cholesterol-lowering statin drugs. It also has shown promise as a treatment for congestive heart failure when used alongside other conventional treatments. "Coenzyme Q10 improves quality of life and energy levels, but doctors aren't sure of the exact mechanism," says Dr. Brent Bauer, director of the Complementary and Integrative Medicine Program at the Mayo Clinic.
Dosage:  50 to 150 mg per day.

Hawthorn
The berries, leaves, and flowers of this shrubby bush, a member of the rose family, have a long history as a heart tonic to treat irregular heartbeat, high blood pressure, and chest pain. Hawthorn relaxes blood vessels and improves central blood flow to the heart, says Mark Blumenthal, founder and executive director of the American Botanical Council. The benefits are attributed to proanthocyanidins in the plant, the same antioxidants found in grapes. A 2003 review of 13 clinical studies published in the American Journal of Medicine showed that hawthorn also provides a significant benefit as an adjunct treatment for patients with congestive heart failure.
Dosage:  160 to 900 mg powdered extract of hawthorn leaf with flowers (available in capsule form), split between two or three doses per day.

Grape-Seed Extract
It is well-known that men and women in France have a relatively low incidence of coronary heart disease despite eating a diet rich in fats. In attempting to decipher "the French paradox," scientists previously focused on resveratrol, a compound found in the seeds and skin of red grapes (and hence wine), for its role in reducing heart disease. According to a newer theory, it's not just the resveratrol that provides protection -- it's also procyanidins, powerful antioxidants in grapes that may help boost the function of blood vessels and prevent heart disease. Grape-seed extract contains both heart-healthy compounds, says Rakel, and was shown to help lower blood pressure in a recent small clinical study at the University of California-Davis.
Dosage:  200 to 300 mg per day.