Researchers found older adults who drank three or more cups of green tea per day had fewer cerebral white matter lesions, though the association was not seen in people with depression or the APOE e4 gene variant.
By yourNEWS Media Newsroom
Daily green tea consumption may be associated with fewer age-related brain lesions linked to dementia risk, according to a large Japanese study of older adults.
Researchers from the Japan Prospective Studies Collaboration for Aging and Dementia analyzed data from 8,766 community-dwelling adults age 65 and older who underwent brain MRI scans between 2016 and 2018. Participants also completed food frequency questionnaires that allowed researchers to compare brain imaging results with daily green tea and coffee intake.
The findings, published in npj Science of Food, showed that people who drank more green tea had fewer cerebral white matter lesions, a type of damage deep in the brain that becomes more common with age and is associated with vascular dementia and Alzheimer’s disease.
The study found a dose-response pattern. Participants who drank about three cups, or 600 milliliters, of green tea per day had roughly 3% fewer white matter lesions than those who drank less than one cup daily. Participants who drank about six cups per day had about 6% fewer lesions.
Coffee consumption did not show a measurable association with white matter lesions, hippocampal volume or total brain volume.
White matter lesions can interfere with communication between regions of the brain. They are considered an important marker of vascular brain injury and have been linked to cognitive decline and dementia.
Researchers said green tea may offer protection because of its high concentration of catechins, particularly epigallocatechin gallate, known as EGCG. These compounds have antioxidant and anti-inflammatory properties that may help reduce damage to blood vessels in the brain.
Unlike black tea, which undergoes fermentation that changes its chemical profile, green tea retains more of these plant compounds.
Dr. Steven Allder, a consultant neurologist at Re Health who was not involved in the research, said green tea’s effect may be tied to its influence on inflammation and oxidative stress.
“Green tea’s catechins may be more effective against white matter lesions than coffee’s compounds, which are mainly chlorogenic acid and caffeine,” Allder said.
The study did not find that green tea consumption was associated with larger hippocampal volume or overall brain volume. That suggests the observed benefit may involve preservation of vascular brain health rather than prevention of general brain shrinkage.
The protective association was not seen in all participants. Researchers found that the link between green tea and fewer white matter lesions disappeared among people with depression and among carriers of the APOE e4 gene variant, the strongest known genetic risk factor for late-onset Alzheimer’s disease.
The study authors suggested that chronic inflammation associated with depression may reduce or counteract green tea’s anti-inflammatory effects. Among APOE e4 carriers, researchers said genetic risk related to amyloid plaque buildup and vascular damage may be strong enough to overwhelm any measurable benefit from green tea.
“These findings indicate that drinking green tea, especially three or more glasses per day, may help prevent dementia,” the study authors wrote, while noting that the study’s cross-sectional design cannot prove that green tea caused the lower lesion burden.
Green tea has long been consumed in East Asia and has been associated in traditional Chinese and Japanese medicine with a range of health benefits. Modern research has linked the beverage to cardiovascular, metabolic and other health outcomes.
The new findings add to evidence that dietary patterns common in Japan, where green tea consumption is widespread, may play a role in brain aging. Earlier research cited in the submitted material found that tea drinkers reduced their risk of neurocognitive disorders by 61%, while the highest-risk individuals lowered Alzheimer’s risk by 86%.
The findings come as dementia cases are projected to rise globally. Researchers estimate the number of people living with dementia could triple to 153 million by 2050, increasing the urgency of identifying low-cost prevention strategies.
Experts cited in the report said three to six cups of unsweetened green tea per day may provide brain-protective benefits, matching the intake range linked to fewer white matter lesions in the Japanese study.
However, health experts also cautioned against excessive consumption. More than three to four cups per day may cause insomnia, gastrointestinal discomfort or, in rare cases, liver injury because of high caffeine or catechin intake.
For people who dislike green tea, standardized green tea extract supplements have shown promise in improving memory test scores among individuals with mild cognitive impairment or Alzheimer’s disease, though supplements may not be appropriate for everyone and can carry different risks than brewed tea.
The Japanese study does not prove that green tea prevents dementia on its own. But researchers said the findings strengthen the case for including green tea as part of a broader brain-health approach that may also include regular exercise, quality sleep and nutrient-dense nutrition.
For older adults without depression or the APOE e4 genetic risk factor, the findings suggest that regular green tea consumption may be linked to measurable protection against brain changes that often precede dementia.
Source: Natural News
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