What it is. An antioxidant made by our bodies, coenzyme Q10 helps to make ATP (adenosine triphosphate), the fuel that allows our cells to do their jobs. Every cell in our bodies contains this antioxidant, but it's most concentrate in heart muscle cells, which require the most fuel. We have plenty of coenzyme Q10 until we hit age 40. After that, our levels take a nosedive.

How it delays aging: Coenzyme Q10 may help prevent or treat many common forms of heart disease, says Peter Langsjoen, M.D., a staff cardiologist at Mother Francis Hospital and the East Texas Medical Center in Tyler. "It provides such dramatic improvement, it's unthinkable for me to practice medicine without it."

Research shows that people with various types of heart disease are deficient in coenzyme Q10, and that the more severe the heart disease, the lower these levels drop. This substance appears to improve the heart's ability to contract. And because it's a powerful antioxidant, coenzyme Q10 also helps prevent "bad" LDL cholesterol from sticking to the walls of the arteries and clogging blood vessels.

Coenzyme Q10 is used to treat a variety of heart conditions, from heart pain (angina) to cardiomyopathy (any non inflammatory disease of the heart muscles). Some studies suggest that this antioxidant helps treat angina by allowing heart muscle cells to use oxygen more efficiently. In a small study of 19 people with cardiomy

opathy conducted by Dr. Langsjoen, those who took 100 milligrams of coenzyme Q10 a day along with their conventional therapy did far better than those who got conventional therapy and a placebo.

Coenzyme Q10 also helps treat congestive heart failure, which occurs when the heart is too weak to pump blood through the body. In a large study conducted by Dr. Langsjoen, 58 percent of people taking coenzyme Q10 improved by one New York Heart Association classification (the standard doctors use to assess heart patients' condition), 28 percent improved by two classes, and 43 percent stopped using one or more drugs.

What you'll find. Coenzyme Q10 can be found in 10 to 200 milligram capsules. Dr. Langsjoen prefers the soft gel supplements prepared with oil because they're better absorbed by the body.

How much to take: As a preventive measure, take from 30 to 60 milligrams per day, says Dr. Langsjoen. He prescribes higher doses 120 to 360 milligrams for people with heart problems.

This nutrient dissolves only in the presence of fat, so if you're using coenzyme Q10 supplements that aren't in gel form, take them with a meal or snack that contains a small amount of fat, says Dr. Langsjoen.

Be aware: Some medications deplete the body's supply of coenzyme Q10 These include cholesterol lowering drugs such as lovastatin (Mevacor). In rare occurrences, a slight decrease in the effectiveness of the blood thinner warfarin (Coumadin) has been observed. Also, if you have heart disease, consult your doctor before taking coenzyme Qio, says Dr. Langsjoen.