Characterization of Dietary Protein among Older Adults in the United States: Amount, Animal Sources, and Meal Patterns

Abstract

Although protein intakes in the United States are widely regarded as adequate, attention has been given to potential inadequacy of recommendations or patterns of intake in older adults. The objectives of this research were to update and expand estimates of protein intake and adequacy in older US adults, with additional focus on contributions of animal source protein. Data were obtained from 1,768 adults aged 51 years and older in the National Health and Nutrition Examination Survey 2005-2006, the Food and Nutrient Database for Dietary Studies, and US Department of Agriculture Standard Reference datasets. Estimates of inadequate intakes ranged from <1% to 5% of men aged 51 to 70 years to 9% to 24% of women aged ≥71 years, depending on whether adjusted or actual body weights were used to calculate grams of protein per kilogram of body weight. Mean usual protein intakes were 94±22 g/day and 56±13 g/day in those same groups, with 15.3%±2.3% and 15.4%±2.4% of energy from protein. Animal sources provided >60% of protein intake, on average. In regression models with energy intake, age, sex, ethnicity, and education as covariables, percent protein from animal sources predicted protein intake and odds of meeting the Recommended Dietary Allowances (P<0.001). Consumption of total and animal-source protein was skewed to the evening meal. Findings highlight the influence of body weight choice (actual vs adjusted) on estimates of protein inadequacy, and suggest the need for careful consideration of protein source in adults at risk for inadequacy. Research is needed to establish optimal protein intakes, sources, and patterns.