Grow Youthful: How to Slow Your Aging and Enjoy Extraordinary Health
Grow Youthful: How to Slow Your Aging and Enjoy Extraordinary Health

Black tea prevents a variety of diseases

Time to enjoy a cuppa. In the Grow Youthful green tea web page, I explain how green tea is usually renowned as the drink with most health and longevity benefits, more than the standard black tea that most people drink. But is this really correct - when is black tea more healthful?

A large study (1) in Singapore showed that black tea may be able to slash the risk of getting Parkinson's disease by almost a third. Researchers found that people who drank the most black tea were 29 percent less likely to develop Parkinson's disease, compared with those who drank little or no black tea. At first the researchers thought the higher level of caffeine in black tea was responsible for the benefit, but it turned out not to be so. Instead, it appears that black tea somehow affects the level of estrogen in a way that prevents Parkinson's. Interestingly, the disease is less common in women than in men, which again points to this female hormone.

In contrast, green tea showed no protective effects against Parkinson's disease.

A 2017 study (2) of 1,700 adults in the USA found that 5% of them had glaucoma. It found that participants who consumed hot tea (normal black tea, with caffeine) daily were 74% less likely to have glaucoma than those who did not consume hot tea. However, the consumption of coffee, iced tea, green tea and decaffeinated tea had no effect on the risk of glaucoma.

All the benefits of tea apply only to black tea. As explained in Grow Youthful, adding milk and sweeteners turns it into a harmful beverage. If you absolutely have to have white tea, then use full-fat cream.


1. Tan, L. C. et al. Differential effects of black versus green tea on risk of Parkinson's disease in the Singapore Chinese Health Study. American Journal of Epidemiology 2008 Mar 1;167(5):553-560.

2. Connie M Wu1, Annie M Wu1, Victoria L Tseng, Fei Yu, Anne L Coleman. Frequency of a diagnosis of glaucoma in individuals who consume coffee, tea and/or soft drinks. British Journal of Ophthalmology. Published online 14 December 2017.