Oral chronic sulforaphane effects on heavy resistance exercise: Implications for inflammatory and muscle damage parameters in young practitioners

Sulforaphane is a phytochemical that is commonly found in broccoli and broccoli sprouts. However, whether chronic sulforaphane ingestion suppresses heavy resistance exercise-induced muscle damage parameters in humans remains unknown. Therefore, this study investigated the effects of oral chronic sulforaphane ingestion on heavy resistance exercise-induced muscle damage parameters.The study had a randomized, double-blind, placebo-controlled, cross-over design. Ten healthy young men (age: 22.0 ± 0.3 y; body weight: 62.6 ± 2.4 kg; height: 171.0 ± 0.1 cm) were administered placebo or sulforaphane (30 mg/d) for 4 wk at the first trial, then after a 4-wk washout period, the participants were administered the opposite treatment for 4 wk at the second trial. The participants were subjected to heavy resistance exercise (bench press, 85% of one-repetition maximum for three times with eight repetitions) after each administration, and blood samples were collected before and at 30 min and 24 h after each exercise session.In this study, 4 wk of sulforaphane intake decreased plasma levels of creatine kinase, especially creatine kinase levels from 30 min to 24 h and baseline to 24 h. Moreover, the change in interleukin-6 levels significantly decreased from baseline to 30 min on prolonged intake of sulforaphane.Together, these findings suggest that the oral chronic intake of sulforaphane suppressed the heavy resistance exercise-induced increase in muscle damage parameter and expression of inflammatory cytokines. The chronic use of sulforaphane may be a novel therapeutic candidate for the prevention of muscle damage in athletes training daily with high-intensity exercise.