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Is Antioxidant CoQ as Powerful as Supporters Claim?


Could an antioxidant with a strange-sounding name hold the answer to congestive heart failure and two debilitating and often-deadly neurological disorders? Could it also boost athletic performance in healthy people, improve memory and combat gum problems?

Those are just some of the health claims for coenzyme Q10, or "CoQ," a substance that proponents such as the Life Extension Foundation, a nonprofit organization based in Fort Lauderdale, Fla., tout as being able to make "old hearts young again." U.S. sales of CoQ, which is available in most places where vitamins and dietary supplements are sold, total about $110 million annually, according to Jed Meese, vice president of Vitaline, one of its makers.

As is often the case with dietary supplements, the science that has been done does not justify all of the claims. But some preliminary scientific evidence for CoQ looks "tantalizing," said Rebecca Costello, deputy director of the National Institutes of Health's Office of Dietary Supplements. In fact, it's been promising enough to launch a $2-million, NIH-sponsored, multi-center pilot study of CoQ in 80 people with early-stage Parkinson's disease and a second federally funded study, a $6.5-million, four-year trial of 347 people with Huntington's disease. The progressive neurological illnesses cause disability and death.

Coenzyme Q10 is produced by mitochondria, the power plants of cells. It was discovered in cow hearts in 1956 by University of Wisconsin biochemist Frederick Crane as he tried to determine how heart cells convert sugar into energy that enables the heart to beat.

At first, Crane and his team thought they might have stumbled upon a new vitamin, which they named Q. But further research showed that it was a coenzyme, a substance that serves as the spark for a chemical reaction in the body. Subsequently, CoQ, also known as ubiquinone, has been found in every human cell that contains mitochondria and is recognized as a key antioxidant, a substance that may help protect against heart disease and cancer.

But even many supporters caution that it's too early to know whether CoQ can play a role in the prevention and treatment of diseases. Results from a variety of clinical trials have often been contradictory.

Crane, who began taking 180 milligrams of CoQ daily about six years ago, cautions that there's still much to be learned about this potent antioxidant before it is widely used as a supplement. "If you are a healthy young person, you're probably making all that you need," he said.


Here's how the health claims and the latest scientific evidence stack up:

Can It Fight Heart Disease?

The most recent published report suggests that it can't.

Because CoQ is found in high concentrations in healthy hearts and at low levels in people with congestive heart failure, researchers surmised that CoQ supplementation might help those with heart disease.

The theory is that CoQ might work in the heart in two ways: as an antioxidant to help thwart damage from free radicals that contribute to arterial blockage and to help boost heart muscle action by improving energy efficiency. Plus, CoQ may boost the effects of vitamin E, also a potent antioxidant with some potential beneficial heart effects. But the scientific evidence for CoQ is mixed.

In 1983, Per Langsjoen, a cardiologist in Tyler, Texas, began some of the first U.S. studies of CoQ in patients with congestive heart failure and found some promising results. He teamed with his son, H. Peter Langsjoen, for follow-up studies of CoQ in people with high blood pressure, as well as in patients with a condition called diastolic dysfunction and in some suffering from mitral valve prolapse. Again, they found that people who took CoQ seemed to improve and published some scientific papers reporting their results.

Although promising, the majority of this research was not randomized or controlled. The few trials testing CoQ against a placebo often produced less-compelling results, but there were some promising leads. A 1998 pilot study of heart-attack patients published in Cardiovascular Drugs and Therapy concluded that coenzyme Q10 could help provide "rapid protective effects" if it was administered within three days of heart-attack symptoms. But the team of scientists also cautioned that more study was needed with a larger group of patients.

In 1999, the journal Biofactors published a 12-week study of 22 people with left ventricular heart failure and found that those who took 200 milligrams daily of CoQ showed significant improvement compared with those who took a placebo.

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