2002-12-01
Harvard Heart Letter

Almost every day readers ask us about herbs or other alternative remedies for high cholesterol, high blood pressure, and cardiovascular problems in general. Answering these questions is one of our toughest tasks.

Why? For most alternative therapies, there's little or no solid science on which to base clear recommendations. That's certainly the case for coenzyme Q10 and policosanol.

Coenzyme Q10

A claim such as "Improves the heart and circulation" is hard to pass up. Maybe that's why the magazine Vitamin Retailer called coenzyme Q10 (CoQ10) one of the "most important dietary supplements of the new millennium."

There's little question that coenzyme Q10 is an important source of revenue for vitamin sellers. There are big questions about whether this supplement is important for your health.

Virtually every cell in your body uses this vitamin-like substance. It helps transfer the energy stored in food into ATP, the body's energy molecule. It helps protect and stabilize cell membranes. And it is a powerful antioxidant.

Heart disease can reduce levels of coenzyme Q10. Does taking it prevent or fight heart disease?

Some studies say yes. In mostly small trials, use of the supplement appeared to lessen chest pain (angina), lower blood pressure, and improve the symptoms of heart failure. Other studies, though, showed that coenzyme Q10 had little effect in these situations.

Some preliminary research suggests that the statin family of cholesterol-lowering drugs interferes with the body's ability to make coenzyme Q10.

Yet a study published last year in the American Heart Journal showed that two commonly used statins, pravastatin (Pravachol) and atorvastatin (Lipitor), had no effect on coenzyme Q10 levels.

A report early this year in Science magazine shows how little we really know about coenzyme Q10 in the diet. Roundworms fed a diet without any coenzyme Q10 lived 60% longer than those with normal amounts in their food. We're certainly not roundworms. But the results suggest that you might not want to load up on this supplement until we know more about it.

Coenzyme Q10 seems to be safe. Side effects are uncommon and minor, such as an upset stomach, nausea, diarrhea, and itching or rash. But it may increase the risk of bleeding or blood clots. If so, it could pose a problem for anyone taking aspirin, clopidogrel (Plavix), or a blood thinner such as warfarin (Coumadin) or heparin.

The best advice right now about coenzyme Q10 is caveat emptor - let the buyer beware. It seems to be safe, but there's no good evidence that it improves heart health. National guidelines on the use of statins and the treatment of congestive heart failure recommend against coenzyme Q10. If you choose to use it, take it as insurance, not as a substitute for proven strategies.

Policosanol

Twenty years ago, Japanese scientists fed wax scraped from sugar cane leaves to rats and pigs. The animals' cholesterol levels fell. Then a Cuban team extracted the active ingredients - a mixture of alcohols - from this wax. This mixture, called policosanol, seems to act like a combination of a cholesterol-lowering statin and aspirin.

Reports indicate that this product lowers levels of LDL (bad) cholesterol in the blood and raises HDL (good) cholesterol. It may keep LDL from oxidation, and so block an early step toward cholesterol-clogged arteries. It also seems to make platelets less sticky, and thus less likely to clump and form clots in the bloodstream.

In comparisons of policosanol and statins, the sugar-cane extract performed quite well. Ten milligrams of policosanol a day lowered LDL levels by 20%-30%, about the same as a low-dose statin. It also increased HDL levels by 10%-20%.

What about safety? In a study of almost 30,000 people who took policosanol for almost three years, 86 reported negative side effects. The most common of these were weight loss, frequent urination, headache, dizziness, and overeating.

On the surface, this evidence looks impressive. Here comes the fine print.

First, almost all of the studies were carried out by a single research team in Cuba. Second, most of the information on policosanol comes from small, short-term studies. Third, and most important, no one knows if policosanol's beneficial effects actually translate into improved circulation or fewer heart attacks and strokes.

For protecting yourself against the dangers of high cholesterol, a healthy diet, exercise, and a statin are still your surest and safest bets. There's solid proof that they not only improve cholesterol levels but protect you against cardiovascular disease.

If you choose to use policosanol, keep in mind that some of what's sold in the United States comes from beeswax. This might have the same effects on cholesterol as policosanol from sugar cane wax. Then again, it might not.

As with any alternative medicine or dietary supplement, tell your doctor you are taking it. And realize that you are taking part in a large and not-carefully controlled experiment.

©2002 President and Fellows of Harvard College