First, Mertz et al. [1] conducted a rigorous 12-month randomized controlled trial in 208 healthy older adults to investigate the effects of daily whey or collagen protein supplementation, with or without supervised resistance training. The findings were conclusive: only the group combining whey protein with progressive resistance exercise achieved significant improvements in quadriceps cross-sectional area and knee extensor strength. Protein supplementation alone failed to prevent muscle decline. These results reinforce the principle that mechanical loading remains essential and that dietary protein is most effective when integrated with structured training. For practitioners, this emphasizes that nutrition should complement—not replace—evidence-based exercise prescriptions.

Second, Alkhedhairi et al. [2] evaluated krill oil supplementation in adults over 65 years of age. In this double-blind, placebocontrolled trial, participants receiving 4 grams of krill oil daily over six months experienced meaningful improvements in knee extensor torque, grip strength, and quadriceps muscle thickness compared with placebo. While no significant changes were observed in certain functional measures, the increases in muscle strength suggest that krill oil may serve as a practical adjunct for maintaining muscle function. The study further supports the broader role of long-chain omega-3 fatty acids in preserving neuromuscular health in older populations.

Finally, Martínez-Arnau et al. [3] investigated whether isolated leucine supplementation could improve sarcopeniarelated outcomes among institutionalized older adults. Over 13 weeks, daily leucine intake (6 grams) significantly improved walking time and respiratory muscle strength, although no significant gains were observed in lean body mass or handgrip strength. Importantly, the authors noted that combining leucine supplementation with resistance exercise might lead to greater improvements in muscle strength and functional performance, as the present trial did not incorporate an exercise intervention.

These findings suggest that targeted amino acid supplementation can contribute to functional preservation, particularly in frail or mobility-limited populations.

Collectively, these studies highlight a consistent theme: nutritional strategies can support muscle health, but their effects depend on dosage, delivery, and combination with exercise. For relatively healthy older adults, integrating progressive resistance training with protein or omega-3 supplementation appears to be the most effective approach. In frailer individuals, isolated leucine supplementation may improve mobility-related outcomes. Future studies should further explore the synergistic effects of combining leucine with structured training protocols.