Drinking three or more cups of green tea per day may help protect the brain from cognitive decline and dementia, according to a recent study from Japan.
Scientists at the Kanazawa University Graduate School of Medical Sciences found a link between drinking green tea and having a smaller volume of white matter lesions on the brain. The study was published in scientific journal npj Science of Food, associated with Nature, on January 7.
White matter lesions, areas of damage or abnormality in the white matter of the brain, often occur as we age and can be asymptomatic.
However, having more white matter lesions can indicate poorer brain health and is associated with cognitive decline, memory issues and some forms of dementia, including vascular dementia and Alzheimer’s disease.
The Kanazawa scientists used data collected for the Japan Prospective Studies Collaboration for Aging and Dementia project, a large study involving eight research centers in Japan.
Between 2016 and 2018, the project collected data using food questionnaires and magnetic resonance imaging (MRI) brain scans.
A stock photo of an old lady holding a cup of tea. Drinking more green tea might protect brain health because of its antioxidant and anti-inflammatory properties, Japanese scientists found.
vbacarin/iStock / Getty Images Plus
Excluding adults who had mild cognitive impairment, dementia or incomplete data, the Kanazawa scientists looked at the data of more than 8,500 adults aged 65 and older.
They categorized participants based on how much green tea and coffee they drank per day and analyzed the MRI scans for white matter lesions, hippocampal volume and total brain volume.
Hippocampal volume means the size of the hippocampus, which is a key part of the brain associated with memory formation, spatial navigation and emotional regulation.
The hippocampus naturally shrinks with age—or it can shrink as a result of chronic stress, mental illness or brain injury—but shrinkage can also be a sign of cognitive decline and some kinds of dementia, including Alzheimer’s disease.
The scientists measured total brain volume because the brain also shrinks with aging, but accelerated reductions in brain volume are associated with cognitive decline and dementia.
Study participants who drank 20 ounces of green tea or more per day—that’s 2.5 cups—were found to have, on average, a 3 percent lower volume of white matter lesions on their brains than those drinking 7 ounces of green tea or less.
Those who drank 50 ounces of green tea per day had white matter volumes that were on average 6 percent lower than the 7-ounces-or-less group.
However, the scientists found no significant links between green tea intake and hippocampal or total brain volume. They also found no significant links between drinking coffee and brain health.
The scientists concluded that the antioxidant and anti-inflammatory properties of green tea might protect blood vessels and promote brain health.
This was an observational study, so the scientists could not prove that drinking green tea caused their study participants’ brains to be healthier.
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Reference
Shibata, S., Noguchi-Shinohara, M., Shima, A., Ozaki, T., Usui, Y., Taki, Y., Uchida, K., Honda, T., Hata, J., Ohara, T., Mikami, T., Maeda, T., Mimura, M., Nakashima, K., Iga, J., Takebayashi, M., Ninomiya, T. & Ono, K. (2025). Green tea consumption and cerebral white matter lesions in community-dwelling older adults without dementia, npj Science of Food, 9(2). https://doi.org/10.1038/s41538-024-00364-w