The role of protein intake distribution across meals in maintenance of physical performance and muscle strength in older adults: An exploratory study based on secondary data analysis of the PRevention Of Malnutrition In Senior Subjects in the EU (PROMISS) trial

Background & aims

There is increasing interest in the impact of protein intake distribution across meals on muscle health and physical performance in older adults, but previous studies have yielded conflicting results. This study aimed to explore the role of protein intake distribution across meals in maintenance of physical performance and muscle strength in older adults with an habitual low protein intake before and during a protein intervention trial.

Methods

Secondary data analysis was performed using data of the 6-month PRevention Of Malnutrition In Senior Subjects in the EU (PROMISS) trial, which focussed on increasing protein intake among community older adults (n=276) with habitual low (<1.0 g/adjusted body weight/d) protein intake. Dietary intake was assessed by 3-day food diaries combined with three 24-hour dietary recalls. We examined the association between protein intake distribution and 400-m walk time and leg extension strength, including cross-sectional associations at baseline and longitudinal associations over six months. The three parameters examined included the number of meals high (≥35 g) in protein, protein distribution across meals assessed by the coefficient of variation, and the percentage of protein intake from breakfast. Additionally, we examined whether these longitudinal associations were modified by the intervention to increase protein intake.

Results

None of the protein intake distribution parameters were associated with 400-m walk time or leg extension strength, neither cross-sectionally nor longitudinally, except for the cross-sectional association between a higher percentage of protein intake from breakfast and slower walking pace in women only (b = 1.8 (95% CI 0.1–3.6)). Longitudinal associations were not modified by the protein intervention.

Conclusion

Distribution of protein intake across meals does not seem to play an important role in maintaining physical performance or muscle strength in older adults with an habitual low protein intake, even if protein intake is increased.