Can the MIND Diet Slow Cognitive Decline in Older Individuals?
In a randomized controlled trial, researchers found no difference in cognition changes nor brain magnetic resonance imaging (MRI) outcomes between older adults who followed a dietary intervention known as the Mediterranean–DASH Intervention for Neurodegenerative Delay (MIND) diet and those with a control diet with basic calorie limits.
The MIND diet is a fusion of the Mediterranean diet (known to improve cardiovascular health) and the Dietary Approaches to Stop Hypertension (DASH) diet (known to improve heart health). The MIND diet modified both the Mediterranean and DASH diets to include foods that have an association with reducing dementia risk like leafy greens and berries.
Although observational studies have shown a connection between dietary interventions on the reduction in cognitive decline, data from clinical trials is limited.
Barnes and colleagues, who performed a two-site, randomized, controlled trial involving older adults without cognitive impairment but with a family history of dementia, a body-mass index greater than 25, and a suboptimal diet, which was determined after participants completed a 14-item questionnaire.
The goal of the study was to determine the cognitive effects of the MIND diet compared with a control diet with mild caloric restriction. The researchers assigned the participants in a 1:1 ratio to follow the intervention or the control diet for 3 years. The primary endpoint was the change from baseline in a global cognition score and four cognitive domain scores, all of which were derived from a 12-test battery.
Barnes and colleagues screened a total of 1929 individuals, of which 604 were enrolled. A total of 301 were assigned to the MIND-diet group and 303 to the control-diet group. According to the results of the study, improvements in global cognition scores were observed in both groups, with increases of 0.205 standardized units in the MIND-diet group and 0.170 standardized units in the control-diet group from baseline to Year 3 (mean difference = 0.035 standardized units; [95% confidence interval; - 0.022 to 0.092]; p = 0.23). On MRI, researchers found that the changes in white-matter hyperintensities, hippocampal volumes, and total gray- and white-matter volumes were similar in both groups.
The study had limitations. For example, considering that the patient population consisted of those mostly of European descent, the authors noted that the results of the trial may not be generalizable for those from diverse backgrounds.
“In this two-site randomized trial involving older adults with a family history of dementia, we found that the participants who followed the MIND diet had small improvements in a global measure of cognition that were similar to those who followed a control diet with mild caloric restriction,” Barnes and colleagues concluded.
Barnes LL, Dhana K, Liu X, et al. Trial of the MIND diet for prevention of cognitive decline in older persons. N Engl J Med. Published online July 18, 2023. doi:10.1056/NEJMoa2302368.