This study looked at whether higher intakes of total flavonoids and their subclasses (flavanones, anthocyanins, flavan-3-ols, flavonols, flavones, and polymers) were associated with a lower risk of developing Parkinson disease (PD). The analysis included 49,281 men in the Health Professional Follow-up Study and 80,336 women from the Nurses' Health Study. The results found men with the highest intake of total flavonoids had a 40% lower PD risk compared to those with the lowest intake. No significant relationship was observed in women. In the subclasses, a higher intake of berries, a rich source of anthocyanins was significantly associated with a lower PD risk. The authors conclude "Our findings suggest that intake of some flavonoids may reduce PD risk, particularly in men, but a protective effect of other constituents of plant foods cannot be excluded".
Gao X, Cassidy A, Schwarzschild MA, Rimm EB, Ascherio A. Habitual intake of dietary flavonoids and risk of Parkinson disease. Neurology. 2012 Apr 10;78(15):1138-45.