Effects of adequate dietary protein with whey protein, leucine, and vitamin D supplementation on sarcopenia in older adults: An open-label, parallel-group study

Abstract

Background & aims: Sarcopenia is defined as a syndrome characterized by declines in skeletal muscle mass and strength or an alteration in physical function. Although some studies showed nutritional supplementation alone might have health benefits for older sarcopenic patients, their results were inconsistent and remain controversial. The objective of this study was to evaluate if a diet with high protein supplementation (Supp) can lead to better improvement than additional protein intake via dietary counseling (Diet) in maintaining the muscle mass and strength among sarcopenic elders.

Methods: This was an open-label, parallel-group (Supp vs. Diet) trial. In total, 56 sarcopenic elders completed this study. All subjects were advised to achieve adequate protein intake (1.2-1.5 g/kg body weight/day). This amount of protein is recommended for the elderly and is thought to prevent or retard muscle loss due to aging. The diet group (n = 28) was recommended to consume an ordinary protein-rich diet via counselling whereas the Supp group (n = 28) received a vitamin D- and leucine-enriched whey protein supplement for 12 weeks. The appendicular muscle mass index (AMMI), handgrip strength, gait speed, and calorie and macronutrients intake were evaluated after 4 and 12 weeks of the diet intervention.

Results: Total energy and protein intake increased in both groups. The Supp group had higher intake than the Diet group. The AMMI increased in both groups, and handgrip strength improved in the Diet group. However, no significant differences in AMMI or handgrip strength were found between the two groups. Compared to the Diet group, the Supp group had better improvement in gait speed after 12 weeks of the supplement intervention especially in subjects younger than 75 years.

Conclusions: The AMMI can be improved as long as sufficient protein is consumed (1.2-1.5 g/kg body weight/day) in sarcopenic elders. Nutritional supplement allows the sarcopenic elderly to more conveniently meet their protein requirements. Supplementation with whey protein and vitamin D can further improve gait speed in elderly sarcopenic subjects, especially in the "younger" age group.

Trial registration: ClinicalTrials.gov NCT03860194.

Keywords: Adequate protein intake; Appendicular muscle mass index; Gait speed; Sarcopenia; Whey protein supplement.