A comparative analysis of effects of daily green tea consumption on non-motor symptoms among community-dwelling older patients with Parkinson's disease

Background Non-motor symptoms (NMS) are prominent features of advanced Parkinson's disease (PD) that contribute to disability severity and quality of life impairment. Polyphenols in green tea are known to offer several health benefits. Aim We examined the effects of daily green tea consumption on NMS in community-dwelling older individuals with PD. Methods Patients were divided into three groups based on their daily green tea consumption: <0.5 L/day ( n = 42), 0.5–1 L/day ( n = 12), and >1 L/day ( n = 24). Summary Patients who consumed green tea daily required significantly fewer medications than those who did not consume green tea daily ( p = 0.042). The proportion of patients with moderate and severe sleep disturbances assessed via the Movement Disorder Society-Unified Parkinson's Disease Rating Scale was significantly lower in the >1 L/day group ( p = 0.029). Sleep disturbances and constipation correlated significantly with daily green tea consumption ( r = −0.35, p = 0.002 and r = −0.28, p = 0.018, respectively). Logistic regression analysis adjusted for age, sex, and number of medications showed that normal and slight sleep disturbances and constipation were significantly associated with daily green tea consumption quantity (odds ratio [OR]: 0.57, 95% confidence interval [CI]: 0.39–0.83, p = 0.004 and OR: 0.71, 95% CI: 0.50–0.99, p = 0.043, respectively). Daily green tea consumption may correlate with reduced sleep disorders and constipation in older patients with PD. Our research generates a new hypothesis that warrants further clinical trials and prospective investigations.