Whey Protein Isolate Supplementation While Endurance Training Does Not Alter Cycling Performance or Immune Responses at Rest or After Exercise

Abstract

This study examined whey protein isolate supplementation combined with endurance training on cycling performance, aerobic fitness and immune cell responses. Eighteen male cyclists were randomly assigned to either placebo (PLA) or whey protein supplementation (WS; 1.0 g·kg body mass −1 ·d −1 in addition to their dietary intake). Both groups completed the identical endurance training program, 4 days per week for 6 weeks. Blood samples were obtained at rest and after 5 and 60 min of recovery from a simulated 40 km cycling time trial (TT) and were repeated after training. Baseline dietary intake of protein prior to supplementation was 1.52 ± 0.45 and 1.46 ± 0.44 g·kg body mass −1 ·d −1 for the WS and PLA groups, respectively. There were similar improvements in TT performance (WS: 71.47 ± 12.17 to 64.38 ± 8.09 min; PLA: 72.33 ± 12.79 to 61.13 ± 8.97 min), and peak oxygen uptake (WS: 52.3 ± 6.1 to 56.1 ± 5.4 mL·kg −1 ·min −1 ; PLA: 50.0 ± 7.1 to 54.9 ± 5.1 mL·kg −1 ·min −1 ) after training in both groups. White blood cells (WBC) and neutrophil counts were elevated 5 min after the TT and further increased after 60 min ( P < 0.05). The exercise-induced increase in WBC and neutrophil counts at 5 and 60 min after the TT were attenuated after training compared to before training ( P < 0.05). Lymphocytes increased 5 min after the TT and decreased below rest after 60 min of recovery ( P < 0.05). Following training lymphocytes were lower after 60 min of recovery compared to before training. There was no change in natural killer cell activity with exercise, training or between groups. It was concluded that whey protein isolate supplementation while endurance training did not differentially change cycling performance or the immune response at rest or after exercise. However, endurance training did alter performance, aerobic fitness and some post exercise immune cell counts.

Supplement with whey protein hydrolysate in contrast to carbohydrate supports mitochondrial adaptations in trained runners

“…However, an almost identical study by Jonvik et al found no difference in these outcomes besides a trend indicating greater increases in leg lean mass for PRO compared to isocaloric CHO (15). These results were similar to the ndings of Forbes et al, demonstrating no difference between PRO (1.0 g kg -1 d -1 ) and isocaloric CHO following six weeks of cycling training (18). In contrast to the two previous trials, Roberson et al recruited runners who received either whey PRO (post training + pre sleep) or a noncaloric placebo pill while they underwent a 10-week progressive running program (17).…”

“…Previous studies, have compared intake of PRO supplementation to an isocaloric CHO beverage (15,16,18) or a <1g sugar pill (17), showing contradicting results in relation to VO 2max and performance tests. One study found PRO to elicit greater increases in VO 2max , 10K TT and lean body mass (16) , while others have found no effect (15,18), or increased lean mass and a trend towards greater 5K TT in placebo (17). Hence, more research is needed to clarify whether PRO supplementation pre and post exercise may have bene cial effects on sports performance.…”

Supplement with whey protein hydrolysate in contrast to carbohydrate supports mitochondrial adaptations in trained runners

“…Previous studies, have compared intake of PRO supplementation to an isocaloric CHO beverage [14,15,17] or a < 1 g sugar pill [16], showing contradicting results in relation to VO 2max and performance tests. One study found PRO to elicit greater increases in VO 2max , 10 K TT and lean body mass [15], while others have found no effect [14,17], or increased lean mass and a trend towards greater 5 K TT in placebo [16]. Hence, more research is needed to clarify whether PRO supplementation pre and post exercise may have beneficial effects on sports performance.…”

Supplements and Nutritional Interventions to Augment High-Intensity Interval Training Physiological and Performance Adaptations—A Narrative Review

“…First, assuming that increases in endurance exercise volume with longer-distance endurance training necessitate the intake of more dietary protein, lower-volume HIIT may not result in the same increase in protein intake needs. Additionally, while 10 weeks of BCAA supplementation (12 g/d) has been shown to increase Wingate peak power and time trial performance in male cyclists [163], there are equivocal data demonstrating that protein supplementation during 6-10 weeks of endurance training fails to promote meaningful improvements in VO 2 peak [164,165], run time performance, cycling time performance [164] or markers suggestive of increased mitochondrial biogenesis [165,166]. While beyond the scope of this review, some of these studies call to question increased protein needs in endurance athletes (e.g., 1.8 g/kg/d) given that participants in non-protein supplemented groups who experienced similar exercise adaptations reported consuming~1.1-1.3 g/kg protein per day [165,166].…”