Abstract

Exercise performance, skeletal muscle repair and physical recovery are influenced by protein and vitamin D. This study investigated the effects of whey protein isolate mixed with vitamin D emulsion gels (WPD-emulsion gels) on body composition and performance recovery in resistance-trained males. Various formulas of WPD-emulsion gels were developed with an optimal daily dose recommended protein content of 28 g from whey protein isolate, 1000 IU of vitamin D and three different amounts of rice bran oil and gelatin. A 9-point hedonic scale study was conducted to identify the highest rating formula on sensory acceptability and the effects on body composition and performance recovery. Eight resistance-trained males aged between 20-40 years old who spent the exercise time over 70% resistance training for 3-5 days per week were chosen to participate. Participants were assigned WPD-emulsion gels consumed 30 min

 after resistance training (4 days/week) for 4 weeks. The study instruments were as follows: anthropometric and dietary assessments, the push-up and sit-to-stand test, muscle recovery times, perceived recovery status scale and rating of perceived exertion. Statistical analysis used one-way ANOVA and Paired t-tests. The results showed that the 5% rice bran with 14% gelatin formula received the highest sensory acceptability score. Skeletal muscle mass (at week 0: 59.9±3.4 kg, at week 4: 61.4±3.0 kg) and fat-free mass (at week 0: 63.1±3.6 kg, at week 4: 64.6±3.1 kg) were significantly increased from week 0 (p<0.05). In addition, participant’s legs muscle mass and exercise recovery were also significantly improved. The study recommends that the consumption of WPD-emulsion gels is beneficial to muscles and could increase fat-free mass and improve exercise performance recovery.

Keywords: Whey Protein Isolate, Vitamin D, Muscle Mass, Fat-Free Mass, Performance Recovery