Fermented Whey Protein Supplement Slows the Progression of Frailty and Sarcopenia Among Older Korean Adults: A Randomized Blinded Trial

As the global population ages, frailty and sarcopenia have emerged as pressing public health challenges due to their impact on functional decline and increased health care burden. This study assessed the efficacy of lactic acid bacteria–fermented whey protein (LAB-FWP) supplementation for improving physical function and nutritional markers in community-dwelling older Korean adults. A total of 45 individuals aged 65 years and older (body mass index 18.5–30) who had not used protein supplements in the prior 6 months were enrolled in a 10-week, randomized, blinded trial. Participants were assigned to either the intervention group (n = 22), which received 38 g/day of LAB-FWP, or the control group (n = 23), which received a taste- and texture-matched dextrin placebo. The intervention group demonstrated significant improvements in physical performance, including an increase in electronic Short Physical Performance Battery (eSPPB) scores (P = .034) and hand grip strength (P = .043). Nutritional biomarkers also improved markedly: dietary vitamin D intake increased from 2.2 to 11.6 µg, calcium intake from 280.9 to 566.7 mg, and magnesium intake from 135.5 to 316.3 mg (all P < .001). Compared with controls, the intervention group showed greater gains in skeletal muscle mass index (Δ = 1.5, P = .004) and eSPPB scores (Δ = 1.4, P = .017). Regression analysis revealed that physical function was positively associated with improvements in nutrition. Daily supplementation with LAB-FWP led to clinically meaningful enhancements in both functional capacity and nutritional status, suggesting its potential as a practical strategy to mitigate age-related frailty and sarcopenia.