MIAMI BEACH — Green tea polyphenols taken daily provide minor symptomatic improvement for people with Parkinson's disease, particularly those with more severe disease at baseline, according to findings in a 12-month study. However, the green tea did not provide any disease-modifying effect, Dr. Piu Chan said.
The study lends some confirmation to observations in China of a dose-dependent protective effect of tea drinking against Parkinson's disease, Dr. Chan said at the World Federation of Neurology World Congress on Parkinson's Disease and Related Disorders.
To determine the safety, tolerability, and efficacy of green tea polyphenols for slowing progression of Parkinson's disease, Dr. Chan and his colleagues conducted a randomized, double-blind, placebo-controlled, and delayed-start study. They enrolled 410 untreated people with Parkinson's disease at 32 sites. Participants were randomized to 0.4 g (102 people), 0.8 g (103), or 1.2 g (104) of green tea polyphenols daily, or placebo (101). At 6 months, the placebo group switched to 1.2 g of green tea polyphenols daily as well.
For comparison, Dr. Chan said two cups of green tea typically contain about 300 mg polyphenols. Patients were assessed at baseline and at 3, 6, 9, and 12 months. They also kept a tea consumption diary. Change in Unified Parkinson Disease Rating Scale (UPDRS) score was the main outcome. Although a significant improvement in UPDRS scores was observed at 6 months for patients in each dosage group, they were no longer significantly different at 12 months compared with placebo.
Although green tea extract was safe and well tolerated, there was “no obvious disease-modifying effect seen,” said Dr. Chan, director, Beijing Institute of Geriatrics and Department of Neurology, Xuanwu Hospital of Capital University of Medical Sciences, Beijing.
“You pretty much don't see a significant difference around 12 months,” Dr. Chan said. There was a 2.5- to 3.5-point increase in UPDRS scores in all groups compared with baseline.
The UPDRS improvement was most marked in the patients with more severe disease at baseline, Dr. Chan said.
Adverse events were similar between groups, with the exception of a slight increase in insomnia in patients treated with green tea polyphenols.
Despite the less than encouraging disease modification results, the study is ongoing. “We are following up with about 2,000 patients now,” he said.
Disclosures: Dr. Chan reported having no conflicts of interest.