Effect of a PROtein-enriched MEDiterranean diet and EXercise (PROMED-EX) on nutritional status and cognitive performance in older adults at risk of undernutrition and cognitive decline: the PROMED-EX randomized controlled trial

BACKGROUND: Undernutrition in older adults is associated with adverse health outcomes including cognitive decline, yet evidence for effective preventive strategies is limited. OBJECTIVES: The objective of this study was to investigate effects of a protein-enriched Mediterranean diet, with and without exercise, on nutritional status and cognitive performance in "at risk" community-dwelling older adults. METHODS: A total of 105 participants (69% female; aged 67.7 ± 6.1 y) at risk of undernutrition and cognitive decline were randomized to 1 of 3 groups: 1) PROMED-EX (personalized dietary counseling plus home-based exercise); 2) PROMED (personalized dietary counseling only); or 3) CON (healthy eating leaflet). The primary outcome was change in nutritional status at 6 mo, measured by the Mini Nutritional Assessment (MNA; 0-30 points). Secondary outcomes included neurocognitive test battery (NTB) z-score, PROMED diet quality score (0-14), physical performance, and health-related quality of life. Analyses followed an intention-to-treat approach using linear regression to assess between-group differences in 6-mo outcomes. RESULTS: At baseline, the mean MNA score was 22.5 ± 2.3. After 6 mo, nutritional status improved significantly in both intervention groups compared with CON: mean differences in MNA were 2.7 [95% confidence interval (CI): 1.3, 4.2] for PROMED and 2.9 (95% CI: 1.5, 4.3) for PROMED-EX (both P < 0.001). Cognitive function also improved, with NTB z-score differences of 0.3 (95% CI: 0.1, 0.5; P = 0.01) in PROMED and 0.2 (95% CI: 0.0, 0.4; P = 0.02) in PROMED-EX compared with CON. Diet quality scores significantly increased with mean differences of 4.0 (95% CI: 2.9, 5.0) for PROMED and 3.9 (95% CI: 2.8, 4.9) for PROMED-EX compared with CON (both P < 0.001). Despite low adherence to exercise, additional benefits were observed for physical performance and quality of life. CONCLUSIONS: Dietary intervention improved nutritional status in community-dwelling older adults at risk of undernutrition. Correcting undernutrition could help to slow cognitive decline and promote physical health and quality of life during aging. This study was registered at clinicaltrials.gov as NCT05166564.