Physiological and Physical Effects of Different Milk Protein Supplements in Elite Soccer Players

Abstract

Brazilian soccer championships involve a large number of teams and are known to cause stress and loss of muscle mass besides other negative physical consequences. This study was designed to compare the effects produced by three types of protein supplements on body composition, biochemical parameters and performance of a top Brazilian professional soccer team during an actual tournament. Twenty-four athletes assessed as having a normal nutrient intake were divided into three groups according to supplementation. Immediately after each daily training, the athletes received 1 g × kg−1 of body weight × day−1 of either whey protein (WP), hydrolyzed whey protein (HWP) or casein (CAS) for eight weeks. Before and after the experimental period, anthropometric characteristics, physical performance by the yo-yo and 3000m tests, and several biochemical variables in blood (uric acid, total cholesterol, HDL-cholesterol, creatinine, glucose) were measured. While no improvement in physical performance was observed with regard to the applied treatments, casein supplementation resulted in muscle mass increase (p<0.039), while WP and HWP favoured the maintenance of the initial muscle mass. Moreover, the eight-week intervention was found to cause no abnormalities in biochemical and anthropometric variables monitored, but instead, the intervention showed to be positive in comparison to the adverse anthropometric changes, when no supplementation was made. It was concluded that supplementation immediately after training sessions with any of the three sources of protein during the competitive period is beneficial and safe, as well as capable of sustaining or even increasing muscle mass.

Functional effects of milk bioactive peptides on skeletal muscle of rats

“…However, such studies did not evaluate the levels of NO. The present results showed that only WPH increased the NO content, which could be an alternative and/or concomitant mechanism of preserving glycogen, as well as a mechanism involved in the capacity of WPH to accelerate muscle recovery, reduce muscle damage (Lollo, Amaya-Farfan, & Carvalho-Silva, 2011) and prolong the permanence of the animal in the exercise. However, none of the tested peptides affected NO.…”

Prehydrolyzed dietary protein reduces gastrocnemial DNA without impairing physical capacity in the rat

“…Morifuji et al (2009) showed that the peptide Ile-Leu, from among seven possible dipeptides containing branched-chain amino acids from the milk-whey proteins, was capable of increasing the uptake of glucose by isolated rat muscle. The reports suggest that far from being unsafe, these alterations are consistent with the observed physiological advantages, such as greater endurance exercise performance, better post-exhaustion glycemic levels, and preserved blood total protein and albumin levels (Morifuji et al, 2009;Faria et al, 2012;Lollo et al, 2011).…”

“…Moreover, it has been observed that a whey protein hydrolyzate is capable of reducing the levels of creatine kinase in both exercising rats (Abecia-Soria, 2010) and soccer players (Lollo et al, 2011), which was originally understood to be the result of the antioxidant capacity of some bioactive peptides present in the hydrolyzate (Peng, Siong and Kong, 2009;Ren et al, 2008).…”

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“…fresh cow milk containing approximately 3.5% total protein, out of which 80 % casein, 15% whey protein, as well as vitamins, and lipids that provides necessary ingredients for growth [1,2]. In other words, energy (carbohydrate) obtained from milk in the form of lactose (sugar), nitrogen (protein; subcomponents of micro fractions) and rich source of calcium (for bones) [3,4]. Most of the biologically active components (e.g.…”

“…lactoferrin, lactoperoxidase, lysozyme, and immunoglobulins etc.) that are present in the whey fraction of milk which showed antimicrobial properties [3,4]. Whey proteins mean that protein which is separated out from the casein and these are purified into different concentrations and are generally useful for wound healing, weight loss, infant health etc.…”