High relative consumption of vegetable protein is associated with faster walking speed in well-functioning older adults

Background: Adequate nutrition and, especially, optimal protein intake are necessary to preserve physical function during aging. Increased consumption of animal-derived protein is often advocated as a strategy to support physical performance in old age. However, there is a lack of empirical evidence to support this claim. Aims: To assess the relationship of protein consumption and specific protein sources with physical function in older adults. Methods: Participants were community dwellers aged 60 years and older recruited in São Paulo, Brazil. Enrollees had their medical books reviewed and were evaluated for anthropometry, physical performance, and diet. Physical performance was evaluated by isometric handgrip strength and walking speed (WS) tests. Diet was assessed using a 24-h recall diary. Results: Ninety older adults were recruited (mean age: 68.0 ± 6.7 years; 87.0% women). Body weight-adjusted protein consumption was significantly associated with upper-limb muscle strength (r = 0.21; p < 0.05), but not with usual (r = 0.09; p > 0.05) or fast WS (r = 0.08; p > 0.05). Conversely, relative protein consumption was correlated with usual WS (r = 0.13; p < 0.05), while fast WS was negatively associated with relative animal protein intake (r = − 0.18; p < 0.05) and positively associated with relative plant-based protein ingestion (r = 0.15; p < 0.05). Discussion: Findings of the present study indicate that different measures of protein intake are associated with distinct components of physical function. In addition, high relative ingestion of vegetable protein is associated with faster WS. Conclusions: A comprehensive dietary evaluation is necessary to appreciate the impact of specific nutrients on physical performance in older people. Future interventional studies are needed to establish the optimal blend of protein sources to support physical performance in old age.