A recent study from Japan has suggested that switching coffee for green tea could help reduce the risk of dementia development in older people. The research looked at older people who had a coffee drinking habit compared to those who had a tea drinking habit.
The study, published in NPJ Science of Food, looked at the data of around 10,000 older Japanese people who were involved in an ongoing observational study on dementia. As part of the study, participants had undergone MRI scans and filled out dietary surveys.
After analysing the data, researchers found a “significant association” between those who drank more green tea and lower cerebral white matter lesions, which are linked with Alzheimer’s disease.
High blood pressure (hypertension) is considered to be “the most important risk factor” for those white matter lesions, according to the researchers, which green tea has been reported to reduce. Green tea also has less caffeine per cup than coffee, which the researchers suggested could also help.
“Green tea consumption may contribute to white matter lesion reduction by improving blood pressure,” the researchers said. “Moreover, green tea contains less caffeine than coffee, which negatively affects blood pressure, thus suggesting that green tea may have a more beneficial impact on white matter lesions.”
Made from the leaves and buds of the Camellia Sinesis plant, green tea contains antioxidants, vitamins and minerals. Whilst the results are certainly interesting as research on dementia continues to grow, the researchers stressed the limitations of the study.
“First, we only investigated green tea and coffee intake when consumed as beverages and did not account for the amount contained in snacks. Importantly, there was also no information on how green tea was brewed, leading to potential variations in the content of bioactive substances.”
The researchers also highlighted that the study only focused on the drinking habits of Japanese individuals, so it was unclear whether similar trends could be observed in other countries. “In conclusion, this study revealed that increased green tea consumption was associated with reduced cerebral white matter lesions,” the researchers said.
“Given that cerebral white matter lesions are closely related to vascular dementia and AD, our findings indicate that drinking green tea, especially three or more glasses per day, may help prevent dementia. Nevertheless, further prospective longitudinal studies and basic research are needed to validate our results.”