August 23, 2019

Effect of a Cup of Green Tea on Treatment of Parkinson's Disease

Parkinson’s disease (PD) is the most common movement disorder and after Alzheimer’s disease (AD), the second most frequent progressive neurodegenerative disease.

The prevalence of PD worldwide ranges from 0.5 to 4 % among people aged 65 years or older. This figure is expected to rise significantly with the accelerated aging of human society. In fact, it was predicted that by 2030, the number of PD sufferers will reach 9.3 million.

PD is characterized by nigrostriatal degeneration which might involve oxidative stress, α-synuclein (αS) aggregation, and neurotoxicity. (1)

Oligomer versions of alpha-synuclein (αS) are emerging as having a key role in Parkinson’s disease. They lead to the generation of fibrils and may cause damage by themselves. (2)

Although the exact cause remains unknown, both genetic and environmental factors have been implicated.

Among the various environmental factors tea consumption has attracted increasing interest, as besides being one of the most consumed beverages in the world, tea contains specific polyphenols which can play an important role in delaying the onset or halting the progression of PD.

There is now consistent mechanistic data on the neuroprotective and neuroregenerative effects of tea polyphenols, indicating that they do not just possess anti-oxidant or anti-chelating properties but may directly interfere with aggregation of the αS protein and modulate intracellular signalling pathways, both in vitro and in animal models. (1)

In a study, the researchers tested 79 different chemical compounds for their ability to inhibit the assembly of alpha-synuclein into fibrils. They found several compounds of interest, but one of them in particular stood out: Epigallocatechin Gallate or EGCG. In this particular study, the researchers found that EGCG has the ability to not only block the formation of alpha synuclein fibrils and stabilize monomers of alpha synuclein, but it can also bind to alpha synuclein fibrils and restructure them into the safe form of aggregated monomers. (2)

In 2009, a double-blind, randomized, placebo-control delayed clinical study to evaluate the safety, tolerability, and efficacy of green tea polyphenols in slowing disease progression in patients with early PD, was conducted by the Chinese Parkinson Study Group (CPSG). 410 untreated people with early PD were enrolled at 32 Chinese Parkinson Study Group sites. Participants were randomized to 0.4, 0.8, or 1.2 g of green tea polyphenols daily or placebo in the first phase of the study, and at 6 months the placebo group switched to 1.2 g of green tea polyphenols daily for 6 more months. Although insomnia was slightly increased, it was found that green tea polyphenols were well tolerated and provided a mild symptomatic relief in early untreated PD.

Data from Chow and colleagues also confirmed that a daily dose of 800 mg caffeine-free EGCG for 4 weeks is safe and well tolerated in healthy human subjects. (1)

According to a study in 2009, consumption of tea more than 3 cups per day delayed age of motor symptoms onset by 7.7 years. The results of this study were published in Parkinsonism & Related Disorders. (3)

EGCG in green tea has been by far the most studied compound and therefore future investigations should address more the effects of other polyphenols, especially theaflavins in black tea. (1)

1- Caruana, M., & Vassallo, N. (2015). Tea Polyphenols in Parkinson’s Disease. In: Vassallo N. (eds) Natural Compounds as Therapeutic Agents for Amyloidogenic Diseases. Advances in Experimental Medicine and Biology, vol 863, 117-137. Springer, Cham. Retrieved from


2- (2016, November 29). Get More EGCG. Drink Green Tea. The Science of Parkinson's disease. Retrieved from


3- Kandinov, B., Giladi, N., &  D.Korczyn, A. (2009). Smoking and Tea Consumption Delay Onset of Parkinson's Disease. Parkinsonism & Related Disorders, 15(1), 41-46. Retrieved from





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