The Effect of Dietary Protein Quality, in Particular the Distribution of Animal and Vegetable Proteins, on the Frequency of Sarcopenia Among Lebanese Older Adults

Background: /Objectives: Sarcopenia is a major age-related health condition characterized by loss of muscle mass, strength and physical performance. While adequate protein intake is essential for maintaining muscle health, the role of protein quality and the distribution of animal and plant protein sources remain unclear. This study aimed to investigate the association between dietary protein quality, particularly the distribution of animal and vegetable proteins, and the frequency of sarcopenia among Lebanese older adults. Methods: A cross-sectional study was conducted among 162 older adults aged >60 years. Food Frequency Questionnaires (FFQ) was used to assess dietary protein intake, and protein sources were classified as animal or plant-derived. Skeletal muscle mass index was calculated as skeletal muscle mass/ height 2, and the sarcopenia cut-off thresholds taken were 7.26 kg/m2 for males and 5.45 kg/m2 for females. Handgrip strength and Short Physical Performance Battery (SPPB) were used to assess physical function and muscle performance. Associations between protein intake, protein source, and sarcopenia were evaluated using appropriate statistical analyses. Results: The frequency of sarcopenia was [49.4%]. Participants with sarcopenia demonstrated lower handgrip strength/muscle mass/physical performance compared with non-sarcopenic participants. A higher skeletal muscle mass percentage (aOR = 0.77), a higher SPPB (aOR = 0.51), and a higher animal (aOR = 0.84) and vegetable (aOR = 0.86) protein intake were significantly associated with lower odds of having sarcopenia. In addition, higher handgrip strength was significantly associated with more animal protein intake, whereas higher SPPB scores were significantly but weakly associated with the total, animal and vegetable protein intake. After adjustment for potential confounders, the observed associations remained statistically significant. Conclusion: In conclusion, both animal and plant proteins contribute to muscle health in older adults, with animal protein having a minor greater positive effect on muscle mass and muscle function. These results highlight the importance of considering protein sources, in addition to total protein intake, when developing nutritional strategies for the prevention and management of sarcopenia. Further longitudinal and intervention studies are needed to establish causality.