(OR05-04-26) Minimally Processed DGA-Aligned Diets Improve Nutrient Sensing and Healthspan Markers in Older Adults: A Randomized Crossover Controlled Feeding Trial

Objectives: This study evaluated whether reducing ultra-processed food (UPF) intake within Dietary Guidelines for Americans (DGA)-aligned vegetarian and omnivorous diets improves health outcomes in older adults and whether responses differ by dietary pattern.

Methods: In the PRODMED2 randomized crossover-controlled feeding trial, 36 older adults (mean age:71.7 ± 5.3 y) completed two 8-week dietary phases separated by a ≥2-week washout. Participants consumed DGA-aligned diets differing by primary protein source: minimally processed pork (MPP) or minimally processed lentils (MPL), each providing < 15%E from UPF. Primary outcomes were fasting insulin and chair-stand performance; secondary outcomes included cardiometabolic biomarkers, nutrient-sensing hormones, DXA-derived body composition, physical function, and neuroactive metabolites. Follow-up assessments occurred ~1-year post-intervention. Outcomes were analyzed using mixed-effects models.

Results: >Both diets led to dietary improvements compared to baseline and unintentional reductions in energy intake (−333 vs −437 kcal/d, MPP vs MPL). Cardiometabolic function improved, with reductions in HOMA-IR, total cholesterol, ApoB, and CRP (all P≤0.001). FGF21 increased (+37.8% vs +51.2%), while leptin decreased (−17.4% vs −22.9%) (both P< 0.05). Participants lost weight (−4.6% vs −5.2%) and fat mass (−9.1% vs −10.1%) (both P< 0.001). Chair-stand performance and handgrip strength were maintained (P >0.05). Neuroactive metabolites (tryptophan, phenylalanine, glycine, and GABA) improved (all P< 0.05). No differences were observed between diets except for HDL (P=0.034). Despite high adherence during the intervention, dietary improvements and health benefits were not sustained at follow-up after the structured feeding phase ended.

Conclusions: Reducing UPF intake within DGA-aligned diets activated nutrient-sensing pathways, evidenced by increased FGF21, and produced improvements in cardiometabolic health, inflammation, adiposity, and neuroactive metabolites independent of protein source. These findings underscore the importance of food-quality guidance alongside nutrient recommendations and suggest sustained UPF reduction may be necessary to preserve healthspan-related benefits.

Funding Sources: National Pork Checkoff