Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 37466280 · doi:10.1056/NEJMoa2302368
What was done
A two-site, 3-year randomized controlled trial enrolled 604 older adults without baseline cognitive impairment who had a family history of dementia, BMI > 25, and a suboptimal diet. Participants were randomized 1:1 to follow either the MIND diet with mild caloric restriction (n = 301) or a control diet with mild caloric restriction (n = 303). Both groups received dietary adherence counseling and weight loss support. The primary endpoint was the 3-year change from baseline in a global cognition score and four cognitive domain scores derived from a 12-test battery (converted to z-scores). Secondary endpoints included MRI-based brain measures (hippocampal volume, white-matter hyperintensities, total gray- and white-matter volumes) in a nonrandom subset.
What was found
A total of 93.4% of participants completed the trial. From baseline to year 3, global cognition scores improved in both groups: by 0.205 standardized units in the MIND-diet group and by 0.170 standardized units in the control group (mean difference, 0.035 standardized units; 95% CI, -0.022 to 0.092; P = 0.23). Secondary MRI outcomes showed no significant differences between groups for hippocampal volumes, white-matter hyperintensities, or total gray- and white-matter volumes.
Why it matters
Observational associations between the MIND diet and reduced dementia risk were not confirmed in this randomized trial, showing no cognitive or neuroimaging advantage of the MIND diet over a calorically restricted control diet over 3 years.
Limits
Both arms received mild caloric restriction and dietary counseling, which produced cognitive improvements in the control group and may have obscured specific MIND diet benefits. The 3-year intervention may be too short to detect differences in dementia onset or structural brain changes. MRI outcomes were assessed in a nonrandom subsample, and findings apply specifically to overweight or obese older adults with a family history of dementia.