Distribution of Daily Protein Intake Across Meals and Lower Extremity Functioning in Community-dwelling Spanish Older Adults: a Prospective Cohort Study

Purpose: Total dietary protein intake has been associated with better physical function in older adults. However, it is unclear whether an even mealtime distribution of protein intake also has an impact on physical functioning. The aim of this study was to examine the prospective association between distribution of daily protein intake across meals and the risk of impaired lower extremity function (ILEF).

Methods: We used information of 2975 individuals ≥ 60 years from the Seniors-ENRICA cohort. Habitual dietary protein intake was assessed in 2008-2010 with a validated diet history. For each participant, dietary protein intake across meals was determined using the coefficient of variation (CV) of the distribution. Study participants were followed up until 2017 to identify incident ILEF, assessed with the short physical performance battery (SPPB).

Results: Over a median follow-up of 6.3 years, we identified 521 participants with ILEF (SPPB ≤ 6). After adjusting for potential confounders including total protein intake/kg/day, a higher CV (less even distribution) of protein intake did not show an association with the risk of ILEF [hazard ratios (HR) and 95% confidence intervals (CI) for second and third vs. the first tertile: 1.08 (0.87-1.34), and 1.06 (0.85-1.32), respectively; p trend = 0.60]. When assessing each component of the SPPB, a higher CV of protein intake was associated with higher risk of impaired standing balance (HR for tertile 3 vs. tertile 1: 1.26 (1.03-1.54); p trend = 0.02).

Conclusion: The mealtime distribution of protein intake was not associated with ILEF. The possibility of a detrimental effect of uneven distribution of protein on standing balance needs to be further investigated.