Randomised, double-blind, placebo-controlled study to evaluate the effect on human strength and endurance after resistance training and supplementation of Vicia faba protein hydrolysate compared with placebo.

Objective: To assess the effects of a Vicia faba protein hydrolysate (VFH) on muscular strength and endurance when combined with resistance training for 56 days compared with exercise alone in a mixed population.

Design: A double-blind placebo-controlled parallel trial.

Participants: 72 healthy men and women aged 19-40, stratified in a 1:1 ratio by gender. Participants were excluded if they performed >3 hours of resistance training per week in the 6 months prior.

Setting: Ontario, Canada. Study performed by KGK Science from August 2023 to January 2024.

Intervention: VFH or silica microcrystalline cellulose is given in five capsules daily for 56 days.

Main outcome measures: Primary outcome: Leg strength via one-repetition maximum for bilateral leg extension. Secondary outcomes: Muscular endurance via repetitions to exhaustion, body composition via dual-energy X-ray absorptiometry, plasma biomarkers via ELISA, quality of life via short form survey (SF-36) questionnaire.

Results: Intergroup analysis revealed a significantly greater increase in leg strength compared with placebo at day 28 (p=0.045) and 56 (p=0.05), respectively. Significantly enhanced muscular endurance was also observed from days 0 to 56 with a difference of 2.2 times in the change in repetitions performed from baseline (p=0.022) and a 21.6% increase compared with the placebo. Significant changes in bone mineral content were reported between groups (p=0.032) with a mean increase of 0.7% gained in the VFH group. The improvements in performance were supported by myokine analysis where VFH was shown to modulate a range of biomarkers associated with glucose homeostasis, bone formation, mitochondrial and metabolic function. Quantitative physical strength gains were consistent with qualitative data which showed significantly improved changes in self-assessed health.

Conclusions: VFH supplementation demonstrated significant improvements in muscular strength, endurance and bone mineral content when compared with placebo. These low-dose, peptide-induced improvements enhance the effects of exercise for musculoskeletal health and have the potential to influence all-cause mortality via muscular strength.

Trial registration number: NCT05946746.