March 19, 2025
Green tea, a traditional beverage in Asia that has become increasingly popular in the United States in recent years, may be good for the brain, according to a new report. While sipping green tea won’t guarantee you won’t develop Alzheimer’s disease or slow its progression, it could lower your risk, the findings suggest.
The study, from researchers in Japan, found that older adults who regularly drank three or more glasses of green tea a day had fewer brain abnormalities known as white matter lesions. White matter is the part of the brain that supports and connects neurons, the nerve cells that allow us to think and remember. White matter typically shrinks as we grow older, developing Swiss-cheese-like lesions even in healthy adults. Having fewer white matter lesions is linked to more robust brain health and a lower likelihood of developing Alzheimer’s disease or other forms of dementia.
For the study, 8,766 older adults in Japan who were free of dementia or serious memory problems were surveyed about their coffee and tea-drinking habits. Researchers also performed MRI brain scans to assess the health of participants’ brains by looking for white matter lesions and measuring brain volume.
The researchers found that on average, those who had three cups of green tea per day had 3 percent fewer white matter lesions compared with those drinking one cup per day. Those who drank seven to eight cups per day had 6 percent fewer lesions compared to those who drank one cup a day. Drinking any amount of green tea, however, did not seem to affect brain volume. Shrinkage of the brain is associated with an increased risk of Alzheimer’s disease.
Drinking coffee did not appear to have the brain benefits seen with green tea in this study, although other studies suggest that coffee may boost cognitive health. Black tea was not included in the study due to the low number of black-tea drinkers among the participants.
“This cross-sectional study found a significant association between lower cerebral white matter lesions and higher green tea consumption, but not coffee consumption, in older adults without dementia, even after adjusting for confounding factors,” such as age, sex, how much exercise participants’ got, and education levels, the authors wrote. “Our findings indicate that drinking green tea, especially three or more glasses per day, may help prevent dementia.” The findings were published in the Nature journal npj Science of Food.
The study showed only an association between green tea consumption and white matter health and cannot prove cause and effect. But the findings build on earlier evidence suggesting that green tea may be good for the brain. A review of studies from 2022, for example, found that for every cup of green tea you drink, your risk of dementia decreases by 6 percent.
Green tea, like other types of tea as well as most fruits and vegetables, contains powerful antioxidant compounds called flavonols that can protect cells throughout the body, including in the brain. Both green and black teas are made from the same herb, Camellia sinensis, but green tea is not fermented and may be more potent.
Earlier research has shown that men and women whose diets were highest in flavonols were less likely to develop Alzheimer’s disease in their later years than those who ate diets low in these compounds. Flavonols also have anti-inflammatory effects, and increasingly, scientists link Alzheimer’s disease and other forms of dementia to increased body-wide inflammation. Studies in animals have found that a diet rich in the compounds may enhance memory and learning skills.
EGCG is the main antioxidant in green tea. It is thought to have benefits for heart and blood vessel health, lowering blood pressure and stroke risk. Scientists are studying the compound for its possible benefits in protecting against cancer as well.
More research is needed to determine whether green tea has actual brain benefits in real life. Rates of Alzheimer’s disease, for example, are not known to be lower in countries where green tea is especially popular, such as China and Japan.
In the meantime, taking a tea break won’t hurt and may help. At the least, a cup of tea can provide a pleasant stress-reducing break during the day, and lower stress levels have been linked to a lower risk for Alzheimer’s disease.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Eric Schmidt, Ph.D. Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Shutaro Shibata, Moeko Noguchi-Shinohara, Ayano Shima, et al: “Green tea consumption and cerebral white matter lesions in community-dwelling older adults without dementia.” Nature npj:Science of Food, January 7, 2025
