Obesity is widely recognized as a major risk factor for cardiovascular and metabolic diseases. Increasingly, scientists are also finding that it can affect the brain, contributing to memory decline and structural changes in regions responsible for learning and cognition. Yet an important question remains: can these effects be prevented or reversed?
A research team led by Assistant Professor Ma Zhiwei from the School of Biomedical Engineering (BME) at ShanghaiTech University, together with collaborators from Shanghai University of Traditional Chinese Medicine, has provided new evidence that a naturally occurring compound found in green tea may help protect the brain against obesity-related damage.
The study, published in npj Science of Food, combined large-scale human data with animal experiments to investigate the effects of epigallocatechin gallate (EGCG), one of the most abundant bioactive compounds in green tea.
From human data to biological mechanisms
The researchers began by analyzing brain imaging and dietary information from nearly 10,000 participants in the UK Biobank, one of the world’s largest biomedical databases.
Among adults with obesity, they found a clear trend: individuals who consumed more green tea tended to have larger hippocampal volume. The hippocampus is a brain region critical for learning and memory, and its atrophy is often considered an early indicator of cognitive decline.
While population studies can reveal associations, they cannot determine whether one factor directly causes another. To investigate further, the team turned to animal models.
Using mice with diet-induced obesity, the researchers administered EGCG at levels comparable to those obtained through regular green tea consumption. Brain imaging and behavioral tests showed that EGCG treatment reduced hippocampal atrophy and improved learning and memory performance.
Looking inside the brain
The team then sought to understand what was happening at the cellular level. Their experiments showed that EGCG helped suppress neuroinflammation, restore insulin signaling in the brain, and normalize autophagy—a cellular process responsible for removing damaged components and maintaining healthy cell function.
These changes helped preserve neuronal connections and supported overall brain health, providing a biological explanation for the improvements observed in both brain structure and cognitive performance.
Building a more complete picture
Beyond the specific findings on green tea, the study highlights an integrated research framework that connects population-level observations with imaging, animal experiments, and molecular mechanisms. This allowed researchers to trace a potential link between dietary habits and brain health with greater confidence than either approach could provide alone.
The researchers hope that similar approaches can be applied to study other nutritional factors and their potential roles in promoting long-term brain health.