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.
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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.
But for every study showing positive effects, there was usually another showing no beneficial results. In the most recent research, Stephen Gottlieb and his colleagues at the University of Maryland Medical Center in Baltimore randomly assigned 55 patients with congestive heart failure to receive either 200 milligrams of CoQ or a placebo daily. The results, which were published last month in the Annals of Internal Medicine, showed no benefit from taking coenzyme Q10 and no adverse effects--except to the wallet. Coenzyme Q10 can easily cost a patient $50 to $100 a month, depending on the dose.
Proponents of CoQ say the study included patients who were too sick to benefit from the supplement and that the dose was not large enough to show effects. But other studies have found positive results from the same 200 milligrams a day--one reason that scientists are still struggling to sort out the pros and cons of CoQ.
“This study was well-executed,” said David Meyerson, a cardiologist at Johns Hopkins Medical Institutions and a national spokesman for the American Heart Assn. “And it found that coenzyme Q10 was of no benefit to these patients at all.”
Can CoQ Cure Gum Disease?
Not exactly. Reports that coenzyme Q10 might somehow bolster the immune system and help the body thwart the bacteria that causes gum disease date from the 1970s. But a comprehensive review of the scientific literature by the British Dental Journal in 1995 found no evidence for the health claims and uncovered studies suggesting that “coenzyme Q10 has no place in periodontal treatment.”
The American Academy of Periodontology agrees with that assessment. “Previous studies were basically uncontrolled observations on small populations using scientific methods not acceptable today,” said the group’s president, Jack Caton.
Can CoQ Relieve Brain Disorders?
Maybe, although definitive answers won’t be available until two NIH-funded studies are completed, which will take at least another year.
The theory is that CoQ temporarily restores mitochondrial activity in cells. There’s some evidence that Parkinson’s disease, Huntington’s disease and some other neurological diseases may impair the mitochondria throughout the body, but particularly in nerve and brain cells. If that’s true, “then coenzyme Q10 might slow the progression of these diseases,” said M. Flint Beal, chairman of neurology at the New York Presbyterian Hospital, Cornell Weill campus. “That’s the hypothesis that we are working on.”
And as a potent antioxidant, CoQ might also help prevent the cell death that occurs in both diseases by blocking buildup of a potent, toxic substance called NMDA.
Preliminary studies in animals and humans look promising. In one, Beal and his colleagues gave CoQ to Parkinson’s patients, and found that it not only reversed, but also normalized some of the mitochondrial defects in their platelets, which help the blood to clot. But the study was too short to determine whether that improvement also translated to fewer neurological symptoms, Beal said.
In another study, at Massachusetts General Hospital in Boston, Walter Korshetz and his colleagues showed that coenzyme Q10 helped lower levels of lactate in the brains of people with Huntington’s disease. Increased lactate levels suggest a problem with energy metabolism in brain cells. When CoQ was stopped, lactate levels rose again, especially in the striatum, which is most affected by Huntington’s. Whether lowering lactate could help improve neurological symptoms is still not known.
Can It Aid Athletic Performance?
In theory, CoQ’s antioxidant effects might improve performance and it could hike the use of oxygen in muscles. Again, the potential appears to outstrip the current scientific literature.
In one study of 25 top-level Finnish cross-country skiers, 94% said CoQ supplementation improved their performance and recovery time compared with 33% of those who took a placebo. But in another randomized trial of 18 European male cyclists and triathletes, half the participants were given CoQ for 28 days. The other half received a placebo. The regimen had “no consistently significant effect” on oxygen, blood pressure, heart rate, blood sugar or several other standard exercise measures, the team of scientists led by S.B. Weston reported in the International Journal of Sports Nutrition in 1997.
