Researchers from the Kanazawa University Graduate School of Medical Sciences in Japan have identified a potential benefit of green tea consumption in preserving brain health. Their findings suggest that regularly drinking three or more cups of green tea daily could help safeguard against cognitive decline and dementia.
Published in the journal npj Science of Food, a Nature affiliate, on January 7, the study explored the relationship between green tea consumption and the presence of white matter lesions in the brain. These lesions are areas of damage or abnormality in the brain’s white matter and are more common as people age, though they often do not cause symptoms. However, an increase in these lesions is linked to deteriorating brain health and can be associated with cognitive impairments, memory problems, and certain types of dementia, such as vascular dementia and Alzheimer’s disease.
The research utilized data from the Japan Prospective Studies Collaboration for Aging and Dementia project, which involved eight research centers across Japan and collected data between 2016 and 2018. This data included dietary information from food questionnaires and brain imaging results from magnetic resonance imaging (MRI) scans.
Focusing on individuals over 65 years old without mild cognitive impairment, dementia, or incomplete data, the researchers analyzed the records of over 8,500 adults. They assessed the participants’ daily consumption of green tea and coffee and examined the MRI results for signs of white matter lesions, hippocampal volume, and overall brain volume. The hippocampus is critical for memory formation, spatial navigation, and emotional regulation, and its size can decrease with age, stress, mental illness, or brain injury.
The findings revealed that participants who consumed at least 20 ounces of green tea daily (approximately 2.5 cups) had, on average, a 3 percent lower volume of white matter lesions compared to those who consumed 7 ounces or less. Moreover, those drinking 50 ounces of green tea daily had, on average, 6 percent smaller volumes of white matter lesions than the low consumption group.
Despite these significant findings regarding white matter lesions, the study did not establish any notable correlations between green tea consumption and the volumes of the hippocampus or the overall brain. Similarly, no significant relationships were observed between coffee intake and brain health.
The researchers suggest that the antioxidants and anti-inflammatory properties of green tea may contribute to protecting blood vessels and supporting overall brain health. However, as this was an observational study, they noted that it does not definitively prove that drinking green tea directly leads to healthier brains.