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

## TL;DR

This study found that including minimally processed red meat in a plant-forward diet can improve health markers in older adults without harming cognitive or physical aging.

## Contribution

The study provides novel evidence on the health effects of minimally processed lean red meat within a plant-forward diet in older adults.

## Key findings

- Including minimally processed pork in a plant-forward diet improved cognitive-related metabolic biomarkers in older adults.
- Both diets reduced fasting insulin, but high-density lipoprotein concentrations were higher after the red meat phase.
- Body weight decreased in both diet phases, with a trend toward less lean mass loss with red meat.

## Abstract

Popular dietary patterns for cardiovascular and cognitive health often emphasize limiting red meat intake. However, evidence specifically examining the effects of minimally processed lean red meat, independent of processed varieties, remains limited.

This study aimed to evaluate the impact of incorporating minimally processed lean red meat into a plant-forward dietary pattern aligned with the 2020–2025 Dietary Guidelines for Americans on markers of age-related cognitive, metabolic, and physical health.

This 18-wk randomized controlled crossover feeding trial tested a red meat diet with 162 g/d minimally processed pork (MPP) against a macronutrient- and energy-matched no-meat control diet with minimally processed lentils (MPL) in ≥65 y older adults. Metabolic biomarkers related to cognitive and physical health were explored. Primary and secondary endpoints comprised 5 cardiovascular markers, 12 nutritional and neurotransmitter measures, and 2 metrics each of body composition and muscular fitness. Data were analyzed with robust mixed-effects models adjusted for covariates.

Thirty-six Midwestern older adults (26/10 females/males; mean age 71.7 y; mean body mass index: 28 kg/m2) completed the study. Cognitive-related metabolic biomarkers improved across both arms. Adoption of the plant-forward diet led to a reduction in fasting insulin after both MPP and MPL phases (P < 0.001), and Single Point Insulin Sensitivity Estimator Index increased after MPP (P = 0.032), with no significant between-diet differences. High-density lipoprotein concentrations were higher post-MPP than post-MPL (P = 0.034). Body weight decreased in both phases (P < 0.05), with a trend toward smaller lean mass loss post-MPP. Grip strength and chair-rise performance were maintained throughout the intervention. Neuroactive metabolites and bioactive amino acid concentrations shifted favorably after both interventions.

Findings challenge the perception that red meat is broadly unsuitable for older adults. Including familiar foods like red meat (pork), 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 in populations where red meat remains popular.

This trial was registered at clinicaltrials.gov as NCT05581953 (12 October, 2022) and NCT06261775 (7 February, 2024).

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