For centuries, green tea has been praised for its numerous health benefits, from promoting heart health to supporting weight loss. Recent research now suggests that green tea may also play a role in preserving brain health and reducing the risk of dementia. A new study conducted in Japan has found that older adults who regularly consume green tea have fewer brain lesions associated with cognitive decline. But how strong is this evidence, and what does it mean for those looking to protect their cognitive function?
The Study: Green Tea and Brain Health
A large-scale study published in npj Science of Food examined nearly 9,000 older adults from the Japan Prospective Studies Collaboration for Aging and Dementia. Participants reported their green tea and coffee consumption through a Food Frequency Questionnaire, and researchers classified their intake into four groups based on daily consumption levels.
To assess the impact on brain health, participants underwent MRI scans measuring cerebral white matter lesions, hippocampal volume, and total brain volume. These lesions are considered a risk factor for dementia and cognitive impairment. After controlling for demographic and medical factors—including age, education, hypertension, and genetic predisposition—the researchers found a significant correlation: those who drank more green tea had fewer white matter lesions. Interestingly, coffee consumption showed no similar effect.
What Makes Green Tea Beneficial?
Green tea is rich in antioxidants, particularly catechins like epigallocatechin gallate (EGCG). These compounds have been shown to:
- Combat oxidative stress
- Reduce inflammation
- Inhibit beta-amyloid aggregation, a key factor in Alzheimer’s disease
Dr. Steven Allder, a neurologist at Re:Cognition Health, noted that these neuroprotective properties could be responsible for the lower presence of brain lesions in green tea drinkers. However, he cautioned that other lifestyle factors, such as diet and exercise, could also influence the results.
Who Benefits the Most?
While the overall findings were promising, the study noted some limitations. Specifically, green tea’s protective effects did not extend to individuals with depression or those carrying the APOE e4 allele, a genetic variant strongly linked to Alzheimer’s disease. Researchers suggest that chronic inflammation and genetic predisposition may counteract green tea’s neuroprotective benefits in these individuals.
Limitations and Future Research
Although the study establishes a strong correlation, it does not prove causation. As a cross-sectional study, it cannot determine whether green tea directly prevents white matter lesions or if other lifestyle factors contribute to this effect. Additionally, the study was conducted in Japan, where dietary habits and genetics may differ from those in other populations.
Experts recommend further research, including long-term clinical trials, to confirm these findings across diverse populations. Future studies should also investigate whether specific brewing methods or additional dietary factors influence green tea’s effectiveness in preserving cognitive health.
Is Green Tea Right for You?
While green tea is generally safe, excessive consumption (more than 3–4 cups per day) can lead to side effects, including insomnia, gastrointestinal discomfort, or, in rare cases, liver toxicity due to high catechin levels.
That said, given the potential benefits and minimal risks, adding green tea to your daily routine may be a simple way to support brain health. Researchers suggest that drinking at least three cups per day may be optimal for reducing dementia risk.
Conclusion
The evidence linking green tea consumption to reduced white matter lesions provides a compelling case for its potential role in preventing cognitive decline. While more research is needed, this study adds to the growing body of literature highlighting green tea’s many health benefits. For those looking to support brain function as they age, incorporating green tea into a balanced diet could be a worthwhile step.
