In the first study of its type, researchers at Emory University and nine other centres nationwide have determined that the naturally occurring compound coenzyme Q10 can slow progressive deterioration associated with the early stages of Parkinson's disease by up to 44 per cent.
This is the first time a study has shown that any nutrient or vitamin might play a role in slowing progression of the disease. The greatest benefits were seen in motor skills and activities of daily life, such as walking, dressing, feeding and bathing.
"We are very encouraged with the results of this small trial, which consisted of 80 Parkinson's patients nationwide. However, a larger, multi-centered, controlled trial is still needed before this treatment can be recommended to patients with a high degree of certainty," said Ray Watts, M.D, professor of neurology at Emory University School of Medicine, and lead investigator of the study.
Parkinson's disease is a progressive disorder of the central nervous system affecting over one million people in the United States. Symptoms include tremor, slowness of movement and stiff muscles. Although certain medications, such as levodopa or L-dopa, can reduce the symptoms of PD, they do not slow the progressive deterioration in function.
Scientific evidence shows that mitochondrial function is impaired in Parkinson's disease patients. Mitochondria produce energy for the cells. Research also shows that levels of coenzyme Q10, which the body uses to aid in energy production, are reduced in the mitochondria of Parkinson's patients. In animal models of PD, scientists have determined that coenzyme Q10 supplements can protect the part of the brain affected by the disorder.
"Because of these findings, we've learned that supplementation of this nutrient, which is often described as an antioxidant, plays a role in helping mitochondria to function better and boost energy production in the cells of PD patients," said Watts.
"The study was designed to test the hypothesis that high doses of coenzyme Q10 would slow the progression of Parkinson's, as measured by movement difficulty or disability," he added.
At Emory, eight Parkinson's disease patients took part in the study, which ended in May 2001. Like the rest of the participants nationwide, they were randomly selected to receive high doses of coenzyme Q10 (300, 600 or 1200 mg/day) or a placebo four times a day. Participants had to be in the early stages of the disease (one to three years following diagnosis) where medications, such as L-dopa, were not yet needed for treatment.
Because the participants were only taking coenzyme Q10 and no other drugs, researchers felt they were able to produce very pure results of the effects of the nutrient. Participants remained in the trial for a maximum of 16 months, or until they needed medications to treat the symptoms of the disease.
A number of clinical tests were performed prior to and during the study to rate the participants' motor abilities, activities of daily living, mental function and mood. To determine the participants' progress, researchers used the Unified Parkinson Disease Rating Scale, which evaluates a patient's abilities through a battery of tests, using a scale of zero-four. Lower scores reflect less impairment and better function.
Halfway through the study the scores among the four groups clearly showed a difference. The groups taking the lowest and intermediate dosages (300 and 600 mg/day) had equivalent or lower scores than the placebo group, while the scores for the group receiving the highest dosage (1200 mg/day) were substantially lower. This pattern of disability reduction continued until the end of the study. The benefit was seen in assessment of mental function and mood, activities of daily living and motor skills.
"This is a very important study with positive results for Parkinson's patients," said Dr Watts, a world-renowned Parkinson's disease researcher. "But we are not at the stage yet where we feel comfortable telling patients to go to their local health food store and purchase coenzyme Q10 as a treatment for the disease. Right now, we know this study shows vitamin-type therapy may slow the progression of movement and motor disabilities associated with the disease, but more studies are needed to determine the true effects of the compound."
He added: "Emory will be involved in some larger coenzyme Q10 studies in the near future, in hopes of finding out these specific effects." Researchers found no safety or tolerability concerns or problems with the administration of coenzyme Q10.
The results of the study are published in today's issue of the American Medical Association's Archives of Neurology and will be discussed at the annual meeting of the American Neurological Association taking place in New York city today.