Key Points

• A recent study highlights the connection between a green-Mediterranean diet and slower brain aging, observed through MRI scans.
• Participants following the Mediterranean diet also consumed 3 to 4 cups of green tea daily.
• Researchers propose that green tea and other plant-based foods may significantly contribute to these benefits.

Aging isn’t just about the number of candles on your birthday cake; it’s also about how our organs, including our brains, age internally. Nowadays, scientists can estimate someone’s “brain age” using MRI scans and compare it to their actual age. If the brain appears older than expected, there’s usually a heightened risk of cognitive issues; conversely, a younger brain age signals better health.

Diet plays a crucial role in supporting brain health, and Mediterranean-style eating patterns are frequently noted for their cognitive benefits. A new analysis suggests a specific enhancement that could potentially benefit brain aging: incorporating green tea into a more plant-centered, polyphenol-rich “green-Mediterranean” diet.

In this research, scientists monitored brain age alongside a range of blood proteins that can indicate inflammation and other important brain-related biology. The findings revealed that individuals on the green-Med diet—essentially a Mediterranean diet with added polyphenols from green tea and other sources—exhibited the most positive protein changes and overall signs of a “younger” brain profile.

How Was This Study Conducted?

This study was a secondary analysis of an 18-month randomized controlled trial called DIRECT PLUS, carried out within a large workplace in Israel. Roughly 300 adults, primarily men, with abdominal obesity and/or dyslipidemia were divided into three dietary groups:

• Healthy dietary guidelines
• A calorie-restricted traditional Mediterranean diet
• A green-Mediterranean diet focusing on increased polyphenol intake

Participants in the green-Mediterranean group received 3 to 4 cups of green tea, walnuts, and a daily shake made with Mankai (duckweed). All groups were also provided with guidance on physical activity. Brain MRI scans were utilized to estimate brain age, and the primary metric was the brain-age gap (the difference between brain age and chronological age). The researchers measured over 80 circulating proteins to find patterns related to changes in brain age over time.

What Did the Study Find?

Two significant proteins—galectin-9 and decorin—were noted: higher baseline levels correlated with an unexpectedly older brain. Over the 18 months, changes in galectin-9 levels were particularly pronounced in the green-Med group compared to those on the healthy-guidelines diet. Furthermore, the overall protein patterns shifted more favorably in the green-Med group.

Exploratory data revealed that consuming about 4 cups of green tea daily and approximately seven servings of walnuts weekly were each linked to greater reductions in galectin-9. Trends related to Mankai showed similar but statistically insignificant results.

The changes at the molecular level support earlier findings from the DIRECT PLUS trial, indicating that both the Mediterranean and green-Mediterranean diets might help in minimizing brain shrinkage, with the latter showing additional benefits. Together, these results imply that adopting a higher-polyphenol Mediterranean approach—where green tea is a daily staple—could foster conditions for slower brain aging.

As with all studies, there are limitations. Most participants were male and faced metabolic risks, which may limit the generalizability of the findings. Additionally, no clear differences were found in standard cognitive evaluations over the 18 months, so the observed protein and MRI changes should be interpreted as biological signals rather than definitive indicators of cognitive shifts. Other brain health biomarkers that weren’t measured might also play a role. Future studies should incorporate a more diverse sample and longer duration.

How Does This Apply to Real Life?

You don’t need a lab to take action. The essential takeaway is simple: build a Mediterranean dietary foundation and incorporate polyphenol-rich “green-Med” elements—with green tea as an easy daily addition.

• Make green tea your go-to. Aim for 2 to 4 cups daily, either hot or iced. If you’re sensitive to caffeine, consider switching to decaf green tea.
• Load up on plants and polyphenols. Try to include a small handful of walnuts almost daily and fill your plate with vegetables, legumes, whole grains, and leafy greens.
• Smart meat swaps. Shift away from red and processed meats in favor of fish and poultry, as promoted in both the Mediterranean and green-Med diets in this study.
• Don’t overlook the basics. Better glucose management and regular physical activity are also believed to contribute to brain benefits, so aim for balanced meals full of fiber-rich carbohydrates, proteins, and healthy fats while staying active.

Our Expert Take

This study highlights that a green-Mediterranean eating approach, incorporating daily green tea, walnuts, and a focus on plant-rich foods while reducing red and processed meat, is associated with younger-looking brains on MRI and favorable shifts in proteins linked to brain aging. It’s not a cure-all, and further research is essential to validate long-term cognitive implications, but incorporating more plant-based Mediterranean meals and enjoying green tea daily appear to be wise choices for brain health.