Many popular healthy eating patterns are associated with better memory and thinking skills, but their long-term effects on cognitive health remain unclear. This is the conclusion of an international team of researchers who combined data from more than 17,000 study participants in the United States and Europe. The findings were published in the Journal of Nutrition.
Scientists analyzed seven dietary patterns considered beneficial to health: the Mediterranean diet, the DASH diet designed to lower blood pressure, the MIND diet, which combines principles of the Mediterranean and DASH diets, and four other eating patterns focused on overall diet quality.
The researchers compared participants’ dietary habits with the results of cognitive assessments, including measures of overall cognitive performance and executive function — skills involved in planning, concentrating, and controlling behavior.
When data from a single time point were analyzed, greater adherence to a continuous Mediterranean diet score was associated with better overall cognitive functioning. Higher executive function scores were also observed among those who followed the DASH diet and this Mediterranean dietary pattern.
However, the findings were less convincing when changes over time were examined. Overall, the researchers found no consistent association between adherence to most of the diets studied and slower cognitive decline. The exception was the MIND diet: in three US research cohorts, adherence to this diet was associated with more favorable executive function outcomes.
The authors emphasize that an association observed when comparing people at the same point in time does not necessarily mean that diet caused the differences. Other lifestyle factors and differences between study participants may also affect cognitive health.
The findings are consistent with those of a large randomized clinical trial that found no significant differences in cognitive outcomes between participants following the MIND diet and those in the control group.
According to one of the study’s authors, Lyn Steffen of the University of Minnesota, both diet quality and physical activity are important for slowing cognitive decline.
Approximately 57 million people worldwide live with dementia, and around 10 million new cases are diagnosed each year. The researchers believe further studies are needed to develop more precise recommendations and better distinguish the effects of diet from other factors associated with brain aging.
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