Mediterranean diets lower blood sugar levels and slow brain shrinkage

Previous research has shown that following either a traditional Mediterranean-style diet or a "green" Mediterranean diet is linked to slower age-related brain shrinkage. Now, researchers may have discovered one reason why. A study published in the November 2024 issue of The American Journal of Clinical Nutrition looked at approximately 300 participants, 88% of whom were men, with abdominal obesity (excess fat around the waist) or high cholesterol levels. Participants were divided into three groups. One followed a healthy, low-calorie diet (the control group), one adopted a traditional Mediterranean diet, and the other followed a variation known as a green Mediterranean diet. A traditional Mediterranean diet emphasizes minimally processed, plant-based foods, such as fruits, vegetables, nuts, beans, whole grains, olive oil, red wine, and small amounts of fish, eggs, dairy, and meats. The green Mediterranean diet places a stronger emphasis on plants, including green tea and duckweed (small flowering aquatic plants), and little if any red and processed meat. Everyone followed their diets for 18 months.

Blood sampling and brain MRI tests were done before the study and at the conclusion. The researchers found that compared with the control group, people who followed either Mediterranean diet had less shrinkage in brain regions crucial for cognitive function, motor control, and processing information. The researchers suggested that the improved blood sugar levels in both Mediterranean diet groups contributed to their better brain health. They also noted that people who consumed higher amounts of green tea (two to four cups daily) and a shake made from duckweed as part of the green Mediterranean diet improved their blood sugar levels and brain health the most.

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