Relative protein intake and associations with markers of physical function in those with type 2 diabetes

To examine the independent associations between relative protein intake (g kg^-1  day ¹ ) and markers of physical function in those with type 2 diabetes, while also comparing with current guidelines for protein intake.

This analysis reports data from the ongoing Chronotype of Patients with Type 2 Diabetes and Effect on Glycaemic Control (CODEC) study. Functional assessments included: Short Physical Performance Battery (SPPB), 60 s sit-to-stand (STS-60), 4-m gait speed, time to rise from a chair (×5) and handgrip strength. Participants also completed a self-reported 4 day diet diary. Regression analyses assessed whether relative protein intake was associated with markers of physical function. Interaction terms assessed whether the associations were modified by sex, age, HbA1c or body mass index (BMI).

413 participants were included (mean ± SD:age = 65.0 ± 7.7 years, 33% female, BMI = 30.6 ± 5.1 kg/m² ). The average total protein intake was 0.88 ± 0.31 g kg^-1  day^-1 . 33% of individuals failed to meet the reference nutrient intake for the United Kingdom (≥0.75 g kg^-1  day^-1 ), and 87% for European recommendations (≥1.2 g kg^-1  day^-1 ). After adjustment, each 0.5 g/kg of protein intake was associated with an 18.9% (95% CI: 2.3, 35.5) higher SPPB score, 22.7% (1.1, 44.3) more repetitions in STS-60, 21.1% (4.5, 37.7) faster gait speed and 33.2% (16.9, 49.5) lower chair rise time. There were no associations with handgrip strength or any interactions.

Relative protein intake was positively associated with physical function outcomes, even after consideration of total energy intake. As a number of individuals were below the current guidelines, protein intake may be a modifiable factor of importance for people with type 2 diabetes.