The effects of Oligo-Fucoidan on muscle function in community-dwelling older adults: A double-blind, randomized, placebo-controlled trial

Background: Sarcopenia, characterized by age-related loss of muscle mass and function, presents a growing public health concern in aging populations. While resistance training remains the gold standard for management, alternative interventions are needed for individuals with limited exercise capacity. Fucoidan, a sulfated polysaccharide derived from brown seaweed, has demonstrated promising biological activities, including potential muscle-enhancing effects. This study investigated the effects of low-molecular-weight Oligo-Fucoidan supplementation on muscle strength, muscle mass, and physical performance in community-dwelling older adults. Methods: In this 12-week, randomized, double-blind, placebo-controlled trial, 60 participants aged ≥60 years were assigned to one of three groups: Oligo-Fucoidan, Oligo-Fucoidan with branched-chain amino acids (BCAA) and vitamin D, or placebo. Outcomes included handgrip strength, calf circumference, appendicular lean mass index (ALMI), five-times sit-to-stand (5STS), six-minute walk test (6MWT), and isokinetic knee extension (KE) strength. Results: Oligo-Fucoidan supplementation significantly improved grip strength (p < 0.001; effect size r = 0.82), with 64.7 % of participants exceeding the minimal clinically important difference. Improvements in 6MWT distance (p < 0.001) were also observed, with 47.1 % of participants surpassing the minimal detectable change thresholds. No significant changes in muscle mass were noted, though the placebo group showed a reduction in calf circumference (p = 0.012). MANOVA of percent changes across six outcomes indicated significant overall group differences, driven primarily by greater improvements in grip strength in the Oligo-Fucoidan supplementation group compared with placebo. No adverse events were reported. Conclusions: Oligo-Fucoidan supplementation improved muscle strength and physical performance in older adults, suggesting its potential as a safe, non-pharmacological intervention for sarcopenia. Further research is warranted to evaluate long-term effects and optimize formulation.