Abstract MP40: Higher Intakes of Animal Protein Helps Maintain Functional Status and Grip Strength in Older Adults in the Framingham Offspring Study

Abstract

Introduction: Dietary protein has been shown to prevent age-related functional decline and strength loss, but few studies have examined the separate effects of animal and plant proteins on these outcomes. Hypothesis: We hypothesized that animal protein might provide greater protection against strength loss and functional decline than plant protein in older adults (aged ≥ 50 years) in the Framingham Offspring Study (FOS). Methods: Dietary protein was assessed using 3-day diet records at exams 3 and 5 in the prospective FOS; intakes were adjusted for body weight using the residual method. Functional status scores (median follow-up 17.3 years) was derived from standardized questionnaires at exams 5-9, while grip strength (median follow-up 10.3 years) was measured by hand-held dynamometer at exams 7-9. Multivariable analyses included Cox proportional hazards modeling, repeated-measures mixed models, and analysis of covariance to adjust for sex, age, education, percent of calories from saturated fats, and physical activity. Models for animal protein were adjusted for plant protein intake and vice versa. Results: Subjects were categorized into 3 categories of sex-specific intakes of animal protein (<50, 50-<70, and ≥70 g/day for men; <45, 45-<65, and ≥65 g/day for women) and plant protein (<20, 20-<26 and ≥26 g/day for men; <17, 17-<22, and ≥22 g/day for women). At the end of follow-up, those with the highest (vs. lowest) animal protein intakes maintained the highest functional status levels (functional score: 20.4 vs.19.0, respectively p=0.0036). Similar results were observed for plant proteins (20.2 vs.18.4 for highest vs. lowest intakes, p ≤.0001). In stratified analyses, higher intakes of both animal and plant proteins, especially in combination with higher levels of activity, were associated with greater preservation of functional status over time. Among more sedentary individuals, dietary protein alone (from both animal and plant sources) protected against functional decline over time (p=0.0015 and p=0.0008 for animal and plant protein, respectively). For grip strength, however, only animal protein protected against decline over 10.3 years (change in grip strength: -0.41 vs. -0.60 kg/yr for highest vs. lowest intakes in men, p=0.0273; -0.15 vs. -0.29 kg/yr for highest vs. lowest intakes in women, p=0.0487). Higher plant protein intake was not associated preservation of grip strength over time. Conclusions: Higher intakes of both animal and plant protein were protective of self-reported functional status in these analyses while only animal protein was associated with the preservation of grip strength among older adults.