Researchers from Queen's University Belfast in Northern Ireland looked at the effect of heart-healthy diets on cognitive performance, including thinking and memory skills. The team published their findings in Neurology, the medical journal of the American Academy of Neurology.
For the study, they investigated 2,621 people with an average age of 25 and followed them for 30 years.
They asked the participants about their diet at the beginning of the study, after seven years, and after 20 more years.
They evaluated the participants’ dietary patterns to see how closely they adhered to three heart-healthy diets: the Mediterranean diet, the Dietary Approaches to Stop Hypertension (DASH) diet, and the A Priori Diet Quality Score (APDQS).
They tested the participants’ cognitive function twice – when they were about 50 and 55 years old.
For every diet, they divided the participants into one of three groups – low, medium, or high – based on their adherence to the diet.
Results showed that those who adhered to the Mediterranean diet or the APDQS diet had less decline in their cognitive function at middle-age.
The DASH diet did not affect cognitive function.
High adherence to the Mediterranean diet was linked to a 46 percent reduction in cognitive decline.
High adherence to the APDQS diet as associated with a 52 percent reduction in cognitive decline.
The researchers also adjusted the results for other factors that could affect cognitive function, such as educational attainment, diabetes, smoking, and physical activity.
Overall, the researchers concluded that greater adherence to the Mediterranean diet and APDQS diet during adulthood was linked to better cognitive performance in middle-age.