New research reveals a clear link between green tea consumption and fewer brain injuries, shedding light on its potential to protect the cognitive health of aging populations.
Study: Green tea consumption and brain white matter lesions in community-dwelling older adults without dementia. Image credits: New Africa / Shutterstock.com
A recent study published in the Nature Portfolio Journal Science of Food reveals that higher consumption of green tea is associated with fewer lesions in the white matter of the brain, a hallmark of dementia.
The impact of tea and coffee on cognition
Tea and coffee, the most popular drinks in the world, contain numerous compounds with neuroprotective properties, including caffeine, polyphenols and vitamins. Green tea, black tea and coffee also contain epigallocatechin gallate, theaflavins, chlorogenic acid and caffeic acid, all of which exhibit antioxidant and anti-inflammatory properties.
Several epidemiological studies have reported that tea and coffee consumption reduces the risk of age-related cognitive decline. Dementia, a neurodegenerative disease that causes cognitive decline, is associated with a wide range of structural changes in the brain, including brain atrophy, hippocampal atrophy, and an increase in white matter lesions in the brain.
Previous studies have reported that green tea consumption is associated with reduced annual atrophy of the hippocampus, while regular coffee consumption can increase the thickness of the cerebral cortex. To further investigate these associations, the researchers of the current study examine the associations between green tea and coffee consumption with brain white matter lesions, hippocampal volume, and total brain volume in an older Japanese population without dementia .
Study design
The current study included 8,766 community-dwelling individuals from the Japan Prospective Studies Collaboration for Aging and Dementia (JPSC-AD), who were recruited between 2016 and 2018. The JPSC-AD is an ongoing community-based observational study of dementia conducted in eight regions. throughout Japan.
Study participants underwent magnetic resonance imaging (MRI) of the brain to assess brain white matter lesions, hippocampal volume, and total brain volume. In addition, all study participants completed a food frequency questionnaire to provide information about their daily intake of green tea and coffee.
About 91% and 82% of the study population reported drinking green tea and coffee, respectively. Study participants with higher daily green tea intake reported significantly higher levels of regular exercise and cognitive function, as well as lower levels of smoking and alcohol consumption and depression. However, individuals with higher daily coffee intake reported significantly higher frequencies of diabetes, smoking habits and heart defects.
Association between green tea or coffee intake and brain changes
Potential confounders adjusted for in the analysis include age, sex, study site, education level, apolipoprotein E (ApoE) ε4 carriage, hypertension, body mass index (BMI), serum low- and high-density lipoprotein cholesterol levels, regular exercise and smoking and drinking habits. The study revealed a dose-dependent relationship: individuals who consumed 600-1500 ml of green tea daily experienced significantly fewer brain white matter lesions compared to those with lower levels of consumption.
After adjusting for these factors, higher daily green tea intake was significantly associated with fewer lesions in the white matter of the brain. However, no significant associations were observed between green tea intake and hippocampal or total brain volumes.
When considering daily coffee intake, no significant associations were observed with brain white matter lesions, hippocampal volume, and total brain volume. This contrasts with some previous studies, which have reported positive effects of coffee on brain health in various populations.
Sensitivity analysis
The associations between green tea or coffee intake and brain changes in the sensitivity analysis were similar to those observed for the entire study population, including participants with normal cognitive functions and mild cognitive impairment.
Notably, strong negative associations were observed between green tea intake and brain white matter lesions in study participants without depression, but not in participants with depression. Similarly, significant negative associations were reported in participants without the ApoE ε4 allele, but not in those with the allele, suggesting that these factors may mediate the protective effects of green tea.
Conclusions
Higher daily green tea intake may significantly reduce the risk of brain white matter lesions in older adults without dementia; however, these benefits were not present in individuals who consumed coffee daily.
Cerebral white matter lesions are considered an independent risk factor for cognitive decline and are associated with vascular dementia and Alzheimer’s disease. Larger white matter lesions typically develop in severe brain atrophy in patients with Alzheimer’s disease.
The main risk factor for white matter lesions is hypertension or increased blood pressure. The beneficial effect of green tea on white matter lesions may be attributed to its antihypertensive effects, as several studies have reported that regular green tea intake can reduce both systolic and diastolic blood pressure.
The beneficial effects of green tea intake were limited to participants without depression and the ApoE ε4 allele. This may indicate that green tea is less effective in individuals with these risk factors for dementia, possibly due to residual confounding or smaller sample sizes in these subgroups. Because depression and the presence of ApoE ε4 are substantial risk factors for dementia, green tea may not effectively reduce white matter lesions in individuals at higher risk for developing dementia, necessitating additional studies in these patient populations.
It is important to note that this study focused on an older Japanese population, and cultural dietary practices may limit the generalizability of these findings to other ethnicities and regions. Further research is needed to confirm these associations in more diverse populations.
Magazine reference:
- Shibata, S., Noguchi-Shinohara, M., Shima, A., et al. (2025). Green tea consumption and brain white matter lesions in community-dwelling older adults without dementia. npj Science of Food. doi:10.1038/s41538-024-00364-w.