A 24-week randomized controlled trial found that a Mediterranean diet intervention improved cognitive function and sustained dietary adherence in older adults at risk for dementia. Improvements persisted for up to 12 months, with notable cardiovascular benefits observed in a subgroup receiving physical activity support.
The MedEx-UK trial enrolled 104 participants (74% female, aged 57-76 years, mean 67.4 ± 4.6 years) across 3 UK centers. Participants were randomized to one of three groups: control, Mediterranean diet (MD), or MD + physical activity (PA). Participants had a mean QRISK2 cardiovascular risk score of 10% or greater and baseline Mediterranean diet adherence below 9 points on the MEDAS scale. Cognitive function was normal at baseline.
The intervention improved MD adherence at 24 weeks (a 3.7-point increase on the 14-point MEDAS scale; 95% CI 2.9, 4.5) and sustained a 2.7-point increase at 48 weeks (95% CI 1.6, 3.7). General cognition (0.22; 95% CI 0.05, 0.35) and memory (0.31; 95% CI 0.10, 0.51) scores improved significantly at 24 weeks, driven by better verbal memory performance. However, no cognitive improvements were maintained at 48 weeks, possibly due to a smaller sample size during follow-up, according to findings published in BMC Medicine.
Secondary cardiovascular benefits in the MD+PA group included reduced pulse pressure variability (-2.9 mm Hg; 95% CI -5.3, -0.5) and Ambulatory Arterial Stiffness Index (-0.07; 95% CI -0.2, -0.02) at 24 weeks. No significant changes were observed in systolic or diastolic blood pressure.
Physical activity, objectively measured at baseline, revealed discrepancies with self-reported data. Participants in the MD+PA group averaged 191 minutes of moderate-intensity activity per week at baseline, despite reporting less than 90 minutes. While PA levels increased by 70 minutes/week in the MD+PA group, no significant between-group differences were observed.
The intervention featured behavioral change techniques, including personalized goals, group sessions, and food vouchers, with high adherence (95% retention at 24 weeks). Participants rated goal setting (4.5/5) and dietary changes (4.4/5) highly, while social support (3.2/5) and self-rewards (2/5) were less favorably received.
The study was powered to detect a 3-point MEDAS score change with 90% power (minimum detectable change: 1.23 points). Limitations included challenges imposed by COVID-19 restrictions, which shifted group sessions online, and the predominantly White, socioeconomically advantaged study population.
The authors declared no competing interests.