Parkinson’s disease is a progressive neurodegenerative disorder characterized by loss of dopamine-producing neurons, motor impairments, and the accumulation of alpha-synuclein, a neuronal protein that regulates synaptic vesicle movements and neurotransmitter release. However, a growing body of evidence suggests that dietary components protect against the development and progression of the condition. A 2015 study found that polyphenols in tea mitigated neuronal loss, motor impairments, and alpha-synuclein accumulation in a primate model of Parkinson’s disease.

Researchers treated a group of monkeys with Parkinson’s disease with a mixture of tea polyphenols, including epicatechin, epicatechin gallate, epigallocatechin, and epigallocatechin gallate (commonly known as EGCG), daily for 80 days. Another group of monkeys received no treatment. The researchers assessed the animals' motor function every two weeks and examined their brains.

They found that treatment with tea polyphenols alleviated motor impairments and neuronal loss in the monkeys and reduced alpha-synuclein accumulation. Monkeys that didn’t receive polyphenols showed marked disease progression.

These findings suggest that tea polyphenols exert neuroprotective properties in a primate model of Parkinson’s disease. Polyphenols are one of the most common classes of bioactive compounds found in plants. Evidence suggests they exert potent anti-inflammatory, antioxidant, and cardioprotective properties. Learn more about polyphenols in our overview article.