Animal protein intake is associated with higher-level functional capacity in elderly adults: The Ohasama study

Objectives: To determine the association between protein intake and risk of higher-level functional decline in older community-dwelling adults. Design: Prospective. Setting: Ohasama Town, Japan. Participants: Residents (N = 1,007; mean age 67.4 ± 5.5) free of functional decline at baseline; follow-up was conducted for 7 years. Measurements: Nutrient and food intakes were determined using a validated 141-item food frequency questionnaire. Participants were divided into quartiles according to intake levels of total, animal, and plant protein. Subscales of the Tokyo Metropolitan Institute of Gerontology Index of Competence subscales were used to assess higher-level functional decline. Logistic regression analysis was used to examine the future risk of higher-level functional decline in relation to protein intake, with lowest protein intake as reference. Results: During the study period, 24.4% of eligible participants reported declines in higher-level functional capacity. After adjustment for putative confounding factors, men in the highest quartile of animal protein intake had significantly lower risk of higher-level functional decline than those in the lowest quartile (odds ratio (OR) = 0.41, 95% confidence interval (CI) = 0.20-0.83; P for trend.01). These associations were not seen in women (OR = 0.76, 95% CI = 0.41-1.34; P for trend.37). No consistent association was observed between plant protein intake and future higher-level functional decline in either sex. Conclusion: Higher protein, particularly animal protein, was associated with lower risk of decline in higher-level functional capacity in older men. Animal protein intake may be a modifiable indicator for early detection and prevention of higher-level functional decline in elderly adults.