Efficacy of the Mediterranean–DASH Intervention for Neurodegenerative Delay + Forest Bathing intervention in improving cognitive function and metabolic health: A single-blind, pilot randomised controlled trial

Abstract

Objectives We hypothesised that the Mediterranean–DASH Intervention for Neurodegenerative Delay (MIND) diet is effective in maintaining/enhancing cognitive function in people of Chinese ethnicity, while forest bathing (FB) can enhance the effect of the MIND diet. The objectives of this study were to examine 1) the preliminary effects of the MIND and FB interventions on the cognitive function and metabolic health of community-dwelling older adults and 2) adherence to the interventions in this population. Design A three-armed pilot randomised controlled trial was conducted. Setting and Participants We recruited community-dwelling older adults with hypertension. Intervention Participants were randomly allocated to three groups at a 1:1:1 ratio: 1) MIND+FB, 2) MIND diet, and 3) control group. Both the MIND+FB and MIND diet interventions lasted 12 weeks. Measurements The outcome measure were cognitive function, measured by the Montreal Cognitive Assessment (MoCA) and metabolic risk factors (i.e. waist circumference and fasting blood glucose) at baseline (T0), at 1 week after the completion of the intervention (T1) and at 1 week after the 3-month intervention (T2). The Friedman test was used to examine the within-group effects over the three time points in the three groups separately. Results Thestudy recruited 48 participants, with a median age of 76 ± 16 years and a median MoCA score of 20 ± 8. Cognitive function improved significantly overtime in the MIND+FB group (w = 0.619, p < 0.001) and the MIND diet group (w = 0.293, p = 0.009), but not in the control group. Metabolic risk factors (i.e. waist circumference and fasting blood glucose) improved significantly in the MIND+FB group from T0 to T2. The MIND dietary pattern was significantly improved in the MIND+FB group from T0 to T1. The BMI was significantly reduced from T0 to T1 in the MIND diet group. No significant between-group differences were observed in the total cholesterol, low-density lipoprotein cholesterol, triglyceride, and systolic blood pressure. Conclusion The MIND+FB intervention and the MIND diet promoted cognitive function and reduced some metabolic risk factors in community-dwelling older adults. These interventions have the potential to be applied in the community to prevent cognitive decline in older adults.