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Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons.
Barnes, LL, Dhana, K, Liu, X, Carey, VJ, Ventrelle, J, Johnson, K, Hollings, CS, Bishop, L, Laranjo, N, Stubbs, BJ, et al
The New England journal of medicine. 2023;389(7):602-611
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Lifestyle interventions targeting diet are a possible approach that could affect public health. Most clinical trials have investigated comprehensive diets, in contrast to dietary manipulation of single foods or nutrients. The aim of this study was to evaluate the effects of a 3-year dietary intervention on cognitive decline and brain-imaging markers of dementia and Alzheimer’s disease in older, cognitively unimpaired adults at risk for dementia because of family history. This study was a 3-year, two-site, randomised, controlled trial. The participants were randomly assigned to follow the MIND diet with mild caloric restriction for weight loss or their usual diet with the same mild caloric restriction for weight loss (control diet). Participants were randomly assigned in a 1:1 ratio. Results showed 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. Authors concluded that brain health, cognitive function and brain imaging outcomes (after 3 years) did not differ significantly between participants who followed the MIND diet and those who followed a control diet with a mild caloric restriction.
Abstract
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.).
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Effect of a Nutritional and Behavioral Intervention on Energy-Reduced Mediterranean Diet Adherence Among Patients With Metabolic Syndrome: Interim Analysis of the PREDIMED-Plus Randomized Clinical Trial.
Sayón-Orea, C, Razquin, C, Bulló, M, Corella, D, Fitó, M, Romaguera, D, Vioque, J, Alonso-Gómez, ÁM, Wärnberg, J, Martínez, JA, et al
JAMA. 2019;322(15):1486-1499
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Excess caloric intake and poor nutritional quality are associated with overweight and obesity. A traditional Mediterranean diet has been shown to reduce all-cause mortality, and in particular to reduce risk of cardiovascular disease, type 2 diabetes mellitus and overweight. The aim of this randomised, prospective, single-blinded study was to evaluate the effectiveness of an intensive lifestyle intervention programme in 6874 overweight or obese men and women with metabolic syndrome in Spain. The intervention group was advised on an energy-reduced Mediterranean diet and exercise and received behavioural support, with initial group sessions and interviews, and monthly follow-up phone calls for one year. The control group received advice on a Mediterranean diet and usual care, with 6 monthly follow-ups. After 12 months, the more intensively counselled patients showed a significantly better adherence to an energy-reduced Mediterranean diet than the control group. They had greater reductions in refined grains, pastries, red and processed meats and greater increases in vegetable, fruit and nut consumption than the control group. The intervention group had also better improvements in cardiovascular risk factors.
Abstract
Importance: High-quality dietary patterns may help prevent chronic disease, but limited data exist from randomized trials about the effects of nutritional and behavioral interventions on dietary changes. Objective: To assess the effect of a nutritional and physical activity education program on dietary quality. Design, Setting, and Participants: Preliminary exploratory interim analysis of an ongoing randomized trial. In 23 research centers in Spain, 6874 men and women aged 55 to 75 years with metabolic syndrome and no cardiovascular disease were enrolled in the trial between September 2013 and December 2016, with final data collection in March 2019. Interventions: Participants were randomized to an intervention group that encouraged an energy-reduced Mediterranean diet, promoted physical activity, and provided behavioral support (n = 3406) or to a control group that encouraged an energy-unrestricted Mediterranean diet (n = 3468). All participants received allotments of extra-virgin olive oil (1 L/mo) and nuts (125 g/mo) for free. Main Outcomes and Measures: The primary outcome was 12-month change in adherence based on the energy-reduced Mediterranean diet (er-MedDiet) score (range, 0-17; higher scores indicate greater adherence; minimal clinically important difference, 1 point). Results: Among 6874 randomized participants (mean [SD] age, 65.0 [4.9] years; 3406 [52%] men), 6583 (96%) completed the 12-month follow-up and were included in the main analysis. The mean (SD) er-MedDiet score was 8.5 (2.6) at baseline and 13.2 (2.7) at 12 months in the intervention group (increase, 4.7 [95% CI, 4.6-4.8]) and 8.6 (2.7) at baseline and 11.1 (2.8) at 12 months in the control group (increase, 2.5 [95% CI, 2.3-2.6]) (between-group difference, 2.2 [95% CI, 2.1-2.4]; P < .001). Conclusions and Relevance: In this preliminary analysis of an ongoing trial, an intervention that encouraged an energy-reduced Mediterranean diet and physical activity, compared with advice to follow an energy-unrestricted Mediterranean diet, resulted in a significantly greater increase in diet adherence after 12 months. Further evaluation of long-term cardiovascular effects is needed. Trial Registration: isrctn.com Identifier: ISRCTN89898870.