Study Uncovers How Mediterranean diet Improves Memory and Cognitive Performance

In a study published in Gut Microbes Reports, researchers at Tulane University School of Medicine found that subjects following a Mediterranean diet developed distinctly different gut bacteria patterns compared to those eating a typical Western diet. These bacterial changes correlated with better memory and cognitive performance.

The study found that rats fed a Mediterranean-style diet rich in olive oil, fish and fiber over 14 weeks showed increases in four beneficial types of gut bacteria and decreases in five others compared to rats eating a Western diet high in saturated fats. These bacterial changes were linked to improved performance on maze challenges designed to test memory and learning.

Specifically, higher levels of bacteria such as Candidatus Saccharimonas were associated with better cognitive performance, while increased levels of other bacteria, such as Bifidobacterium, correlated with poorer memory function.

The Mediterranean diet group also showed better cognitive flexibility — the ability to adapt to new information — and improved working memory compared to the Western diet group. They maintained lower levels of "bad" LDL cholesterol.

The researchers used young rats approximately equivalent in age to 18-year-old humans to model the effects of diet during a critical developmental period. The diets were based on human consumption and used ingredients reflecting the complexity of human diets. The Mediterranean diet (MeDi) showed clear benefits for cognitive flexibility, memory, and gut health, suggesting potential parallels in young adults whose brains and bodies are still maturing.

“Our findings suggest that the Mediterranean diet or its biological effects could be harnessed to improve scholastic performance in adolescents, or work performance in young adults,” said corresponding author Dr. Demetrius M. Maraganore, Herbert J. Harvey, Jr. Chair of Neurosciences. “While these findings are based on animal models, they echo human studies linking the Mediterranean diet to improved memory and reduced dementia risk.”

Reference: Solch-Ottaiano, R. J., Engler-Chiurazzi, E. B., Harper, C., Wasson, S., Ogbonna, S., Ouvrier, B., … Maraganore, D. M. (2024). Comparison between two divergent diets, Mediterranean and Western, on gut microbiota and cognitive function in young sprague dawley rats. Gut Microbes Reports, 1(1), 1–21. https://doi.org/10.1080/29933935.2024.2439490