Surprising Results from a Study of the MIND Diet and Its Effects on Cognition

Results of a recent study published in The New England Journal of Medicine suggest that adherence to the Mediterranean–DASH Intervention for Neurodegenerative Delay (MIND) diet may not significantly decrease risk of dementia compared to mild caloric restriction. Participants who followed either diet both experienced moderate increases in global cognitive scores over the course of the 3-year study, but the difference in scores between the two groups was nonsignificant. The MIND diet is a synthesis of the Dietary Approaches to Stop Hypertension (DASH) diet and the Mediterranean diet, which was developed specifically to help in efforts to reduce cognitive decline.

In a phase 3 randomized controlled trial (NCT02817074), 604 older adult participants (aged 65 to 84 years) with a body mass index (BMI) over 25, suboptimal diet, and family history of dementia, were assigned to adhere to the MIND diet (n=301) or control diet (n=303). Only participants without cognitive impairment were included, and all participants adhered to mild caloric restriction with counseling. The primary outcomes of the study were change from baseline to 3 years in global cognitive function measured by 12 cognitive tests, as well as change in specific cognitive domains. Researchers also evaluated volume changes in brain MRI at 3 years as a secondary outcome.

After 3 years, the MIND group showed an improvement of .205 standardized units in global cognition score, while the control group improved by .170 standardized units. The mean difference in global cognitive score change between the groups was nonsignificant, at .035 standardized units (95% CI, –.022 to .092; P=.23). MRI measurements were also similar across both groups. These findings suggest that adherence to the MIND diet may not benefit cognitive or brain MRI outcomes more than a control diet with mild caloric deficit.