Effects of Minimally Processed Red Meat Within a Plant-Forward Diet on Biomarkers of Physical and Cognitive Aging: A Randomized Controlled Crossover Feeding Trial

BACKGROUND: Popular dietary patterns for cardiovascular and cognitive health such as the Mediterranean and MIND diets emphasize plant-based foods while limiting red meat intake. However, most research combines processed and unprocessed forms, limiting conclusions about unprocessed red meat. OBJECTIVE: To evaluate the effects of incorporating minimally processed lean red meat into a nutrient-dense, plant-forward, healthy dietary pattern on markers of aging-associated health decline. METHODS: This 18-week all-food-provided randomized controlled crossover feeding PRODMED2 trial tested an omnivorous red meat diet with 162g/d minimally processed pork (MPP) against a macronutrient- and energy-matched no-meat control diet with minimally processed lentils (MPL). Serum biomarkers relevant to metabolic-related cognitive and physical health were explored in 36 adults aged ≥65 years. Primary and secondary endpoints included five cardiovascular-related markers, 12 nutrition- and neurotransmitter-related measures, two metrics of body composition, and two muscular fitness outcomes. Data was analyzed using robust mixed effects models adjusted for covariates. RESULTS: Intervention diets were well tolerated, with high adherence. Improvements in cognitive related metabolic biomarkers were observed across both arms. Fasting insulin declined more after MPP ( p < 0.001), with a corresponding increase in SPISE ( p = 0.032), though between-group differences were not significant. HDL was higher post-MPP than post-MPL ( p = 0.034). Body weight decreased in both arms ( p < 0.05), with a smaller lean mass loss trend following MPP. Grip strength and chair-rise performance were maintained. Neuroactive metabolites and bioactive amino acid profiles shifted favorably in both arms. CONCLUSION: These findings challenge the perception that red meat is broadly unsuitable for older adults. Including familiar foods like red meat, particularly in minimally processed form and within a healthy overall dietary pattern, may provide age-associated health benefits and improve adherence to plant-forward diets. These results have important implications for healthspan of older U.S. populations where red meat remains popular. CLINICAL TRIAL REGISTRY: Registered at www.clinicaltrials.gov as NCT05581953 and NCT06261775 .