WEDNESDAY, May 16, 2007 (HealthDay News) -- Low doses of an antioxidant called coenzyme Q10 (CoQ10), sold as a dietary supplement, do not appear to improve Parkinson's disease symptoms, a German study finds.
It's believed that a malfunction of the mitochondria (the part of a cell that converts food to energy) may play a role in Parkinson's disease. CoQ10 also affects mitochondrial processes, according to background information in the study.
"Because of these functions, CoQ10 has attracted attention concerning neuroprotective actions in neurodegenerative disorders linked to mitochondrial defects or oxidative (oxygen-related) stress, such as Huntington's disease and Parkinson's disease," the study authors wrote.
They noted that previous studies had suggested that high doses (1,200 milligrams) of CoQ10 may slow the physical deterioration (such as tremors and movement problems) in people with Parkinson's disease.
In this new study, researchers at the Technical University of Dresden studied the effects of CoQ10 in Parkinson's patients who did not have changes in their motor function and were on stable treatment for the condition.
The patients were divided into two groups. The treatment group of 55 patients took 100 milligrams of CoQ10 three times a day for three months, followed by a two-month "washout" where they did not take the antioxidant. The other 51 patients took a placebo.
Both groups were assessed for Parkinson's symptoms before the start of the study, each month during treatment, and again after the washout period. After three months, blood levels of CoQ10 in the treatment group increased from an average of 0.99 milligrams per liter to 4.46 milligrams per liter.
But the study found that CoQ10 did not improve Parkinson's disease symptoms.
The findings were published online Monday in the Archives of Neurology and are expected to appear in the July print issue of the journal.
More information
The American Academy of Family Physicians has more about Parkinson's disease.
