While the benefits of following a Mediterranean diet are well established, a new study suggests that the fresh-forward, olive oil-soaked eating style can boost brain health by promoting certain gut bacteria.
Researchers at Tulane University School of Medicine found that lab rats who followed a Mediterranean diet developed different gut bacteria patterns than those who adhered to a Western diet.
The study, published in Gut Microbes Reports, found that the bacterial changes associated with the Med diet led to improved cognitive performance.
“We’ve known that what we eat affects brain function, but this study explores how that could be happening,” lead author Rebecca Solch-Ottaiano, PhD, a neurology research instructor at Tulane’s Clinical Neuroscience Research Center, said.
“Our findings suggest that dietary choices can influence cognitive performance by reshaping the gut microbiome.”
The Mediterranean diet, crowned the best overall for eight years running by US News & World Report, is a plant-based diet that prioritizes vegetables, fruits, whole grains, healthy fats, nuts and seeds while limiting red meat and sugar.
The Mediterranean diet has been shown to aid weight loss, improve blood sugar, and lower blood pressure and cholesterol. It’s also been linked to a lower risk of heart disease, stroke, dementia and certain types of cancer.
This latest Tulane study is the first to investigate the relationship between Mediterranean and Western diets, microbiota and cognitive function.
To model the effects of diet during a critical period of development, researchers recruited rats equivalent to 18-year-old humans.
The researchers found that rats who were fed a Mediterranean diet, complete with a high intake of olive oil, fish and fiber, showed a marked increase in beneficial gut bacteria compared to those who consumed a high-fat, low-veg, meat-heavy Western diet.
The bacterial shifts in the Mediterranean rats, which included higher levels of bacteria such as Candidatus Saccharimonas, correlated to improved cognitive performance and memory. In contrast, the increased levels of certain bacteria, such as Bifidobacterium, in Western rats correlated to impaired memory function.
Previous studies have established a link between a Western diet and cognitive decline, as well as obesity, plummeting sperm counts, and emotional and behavioral issues.
Researchers noted that the Mediterranean diet group also showed higher levels of cognitive flexibility, IE, the ability to adapt and integrate new information, compared to the Western diet group. The Mediterranean rats also maintained lower levels of “bad” LDL cholesterol.
The clear benefits of adhering to the Med diet suggest that similar effects could be mirrored in young adults whose brains and bodies are still developing.
“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.”
Based on these findings, researchers are calling for large-scale human studies to investigate the relationship between cognitive function, diet, and gut bacteria.
