Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons.

BACKGROUND: Findings from observational studies suggest that dietary patterns may offer protective benefits against cognitive decline, but data from clinical trials are limited. The Mediterranean-DASH Intervention for Neurodegenerative Delay, known as the MIND diet, is a hybrid of the Mediterranean diet and the DASH (Dietary Approaches to Stop Hypertension) diet, with modifications to include foods that have been putatively associated with a decreased risk of dementia. METHODS: We performed a two-site, randomized, controlled trial involving older adults without cognitive impairment but with a family history of dementia, a body-mass index (the weight in kilograms divided by the square of the height in meters) greater than 25, and a suboptimal diet, as determined by means of a 14-item questionnaire, to test the cognitive effects of the MIND diet with mild caloric restriction as compared with a control diet with mild caloric restriction. We assigned the participants in a 1:1 ratio to follow the intervention or the control diet for 3 years. All the participants received counseling regarding adherence to their assigned diet plus support to promote weight loss. The primary end point 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. The raw scores from each test were converted to z scores, which were averaged across all tests to create the global cognition score and across component tests to create the four domain scores; higher scores indicate better cognitive performance. The secondary outcome was the change from baseline in magnetic resonance imaging (MRI)-derived measures of brain characteristics in a nonrandom sample of participants. RESULTS: A total of 1929 persons underwent screening, and 604 were enrolled; 301 were assigned to the MIND-diet group and 303 to the control-diet group. The trial was completed by 93.4% of the participants. From baseline to year 3, 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 (mean difference, 0.035 standardized units; 95% confidence interval, -0.022 to 0.092; P = 0.23). Changes in white-matter hyperintensities, hippocampal volumes, and total gray- and white-matter volumes on MRI were similar in the two groups. CONCLUSIONS: Among cognitively unimpaired participants with a family history of dementia, changes in cognition and brain MRI outcomes from baseline to year 3 did not differ significantly between those who followed the MIND diet and those who followed the control diet with mild caloric restriction. (Funded by the National Institute on Aging; ClinicalTrials.gov number, NCT02817074.).

Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) study: Rationale, design and baseline characteristics of a randomized control trial of the MIND diet on cognitive decline.

Alzheimer's dementia (AD) is the sixth leading cause of death in the U.S., with an estimated $305 billion cost of care in 2020. Currently there are no cures or therapies to ameliorate the disease progression and symptoms. Growing evidence links a diet characterized by high antioxidant components with benefits to cognitive function, which is indicative of the preventative potential of dietary inteventions. The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) study is a 3-year, multicenter, randomized controlled trial to test the effects of the MIND diet on cognitive function in 604 individuals at risk for AD. Men and women ages 65 to 84 years were recruited. Eligible participants were randomized to either the MIND diet with mild caloric restriction or their usual diet with mild caloric restriction. Cognitive assessments, medical history, blood pressure, anthropometric measurements, and blood and urine sample collections will be taken at baseline and follow-up visits. MRI scans will be completed on approximately half of the enrolled participants at the start and end of the study. Unique features of the MIND study include: 1) a dietary pattern, rather than single nutrient or food, tested in an at-risk population; 2) foods featured as key components of the MIND diet (i.e. extra-virgin olive oil, blueberries, and nuts) provided for participants; and 3) MRI scans of brain structure and volume that may provide potential mechanistic evidence on the effects of the diet. Results from the study will be crucial to the development of dietary guidelines for the prevention of AD.