Sources and distribution patterns of protein intake in patients with cancer: Associations with muscle mass and...

Sarcopenia, characterized by the progressive loss of skeletal muscle mass and function, is a prevalent condition among patients with cancer. The present study aimed to evaluate the source(s) and distribution of protein intake, and its association with muscle mass and strength in this patient population.

This multicenter longitudinal cohort study included data from 5079 patients diagnosed with cancer across China, stratified according to daily protein intake: low (<0.8 g/kg/day); moderate (0.8-1.0 g/kg/day); adequate (1.0-1.5 g/kg/day); and high (≥1.5 g/kg/day). Protein sources and meal distribution patterns were assessed. Muscle outcomes included fat-free mass index (FFMI) and handgrip strength (HGS). Associations were identified using least absolute shrinkage and selection operator regression and compositional data analysis.

The median total protein intake among patients with cancer was 55.00 g/day (interquartile range 40.67-71.00 g/day), primarily dietary (87.30 %), with nutritional supplements comprising 12.70 %. Red meat remained the dominant animal protein source across all intake levels. Intake of poultry, fish, seafood, whey, and plant-based supplements increased with increasing intake, whereas intake of eggs, dairy, and casein decreased. The coefficient of variation for total protein intake across the 3 main meals was 0.44 (interquartile range 0.32-0.58), exhibiting a decreasing trend from the low to high protein-intake groups. Among nutritional supplements, whey protein was significantly associated with a higher FFMI than the combined intake of casein and plant-based proteins (estimate = 0.134, p = 0.041). In the animal-based dietary group, poultry and red meat intakes were positively associated with both FFMI (estimates = 0.171 and 0.480; P = 0.008 and 0.015, respectively) and HGS (estimates = 0.464 and 0.607, respectively; p = 0.004 and p < 0.001, respectively).

Protein sources and temporal distribution were associated with muscle mass and strength in patients with cancer.