For centuries, people have lauded green tea for its myriad health benefits. A recent study from Japan provides compelling evidence that this age-old beverage may help fight cognitive decline and reduce the risk of dementia. Conducted in Japan and published in npj Science of Food, the study found a significant link between regular green tea consumption and fewer cerebral white matter lesions in older individuals. These lesions are associated with an increased risk of dementia, suggesting that green tea might be a powerful ally in preventing this condition.
The research meticulously adjusted for various medical factors such as hypertension, diabetes mellitus, and the presence of the APOE e4 allele, a genetic variant that heightens dementia risk. Researchers also considered body mass index (BMI), cholesterol levels, smoking and drinking habits, as well as electrocardiogram abnormalities. Regular exercise, cognitive function, and depressive symptoms were included in the analysis to provide a comprehensive understanding of the factors influencing dementia risk.
The study categorized daily green tea intake into four groups: 0–200 ml, 201–400 ml, 401–600 ml, and at least 601 ml. The data indicated that higher consumption correlated with fewer cerebral white matter lesions. However, due to the low number of black tea drinkers in Japan, the study could not compare the effects of green and black teas directly.
Allder, a notable researcher involved in the study, highlighted some key findings and areas for future research:
“the absence of benefits in individuals with depression might be due to the interaction between chronic inflammation and oxidative stress associated with depression, which could counteract the neuroprotective effects of green tea.” – Allder
Moreover, Allder noted the complexity surrounding APOE e4 carriers:
“Similarly, the lack of effect in APOE e4 carriers suggests a genetic predisposition that could diminish green tea’s impact, potentially due to APOE e4‘s strong association with amyloid pathology and vascular contributions to cognitive impairment,” – Allder
Interestingly, the study also pointed out differences between the effects of green tea and coffee:
“Unlike green tea,” he added, “coffee did not show similar benefits, possibly because green tea’s unique composition, such as catechins, might be more effective against white matter lesions than coffee’s compounds, which are mainly chlorogenic acid and caffeine.” – Allder
While the findings are promising, Allder emphasized the need for extended research:
“Long-term investigations are necessary to evaluate the impact of green tea consumption on the progression of dementia and cognitive decline. Additionally, comparative analyses should be carried out to assess how green tea compares with other beverages or dietary interventions in preventing white matter lesions,” – Allder
“research should also focus on targeted subgroups, such as individuals with depression or the APOE e4 allele, to explore the mechanisms that might limit green tea’s effectiveness in these populations.” – Allder
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