Published in the Journal of the International Society of Sports Nutrition, the study investigated the effect of probiotic and casein supplementations, individually or in combination over four weeks, on improving the aerobic capacity of soccer players.
The authors from the Department of Sport Science at Shiraz University, Iran, concluded that, in comparison to placebo (PLA), participants provided with a combination of probiotics (PRO) and casein (CAS) supplements exhibited a significant improvement in aerobic endurance indicators, particularly time-to-exhaustion (TTE) and Hypocapnic Hyperventilation area Time (Time-HHV).
Probiotics and protein supplements in soccer players
Soccer players undergo intense physical training and participate in matches that lasting up to 120 minutes. Furthermore, hectic travel schedules, psychological stress and sleep disturbances also elevate the risk of depression and gastrointestinal infections, affecting their performance.
Proper gut microbiome composition is essential to maintaining natural homeostasis in the human body. A previous study revealed that soccer players that introduced multi-strain probiotic supplements exhibited improved aerobic power, training load tolerance and time to reach fatigue.
The consumption of proteins, such as casein, enhances recovery speed and strength after physical activity. A combination of probiotic and protein supplements accelerates muscle recovery and reduces the pain that develops during muscle-damaging resistance exercises
Probiotics also help improve soccer players’ performance by postponing fatigue and enhancing time to exhaustion (TTE). These changes in RCP and TTE increase the hypocapnic hyperventilation (HHV) area period. Additionally, it is hypothesized that the consumption of probiotic supplements with casein protein can affect the endurance performance of soccer players.
Study details
The study recruited 44 male soccer players from the Iran Soccer League. The average age, weight and height of the players was about 23 years, 67 kgs and 178 cm.
After familiarizing themselves with the experimental setting, the participants underwent the Bruce test on the treadmill to assess heart health. They were then randomly assigned to four groups—probiotic (PRO), casein (CAS), casein and probiotic (CAS+PRO) and placebo (PLA). Each group (11 participants) was instructed to take supplements on training days, three times a week for a month.
The members of the PRO group were provided with one probiotic capsule during dinner that contained a total dose of 4.5 × 1011 CFU. Each probiotic capsule contained strains of Lacticaseibacillus casei BP07, Lactiplantibacillus plantarum BP06, Lactobacillus acidophilus BA05, Lactiplantibacillus plantarum BP06, Bifidobacterium breve BB02, Bifidobacterium infantis BI04, Bifidobacterium longum BL03, Streptococcus salivarius thermophilus BT01 and Lactobacillus delbrueckii BD08 bulgaricus.
The CAS group participants consumed 20 g of casein powder 45 minutes before bed while the PRO+CAS group members received one probiotic capsule during dinner and casein powder (20 g) 45 minutes before bed. The participants in the PLA group received one capsule that contained 5 g of starch during dinner.
Multiple aerobic endurance indicators, such as the maximal oxygen consumption (VO2max), Ventilatory Threshold (VT), TTE, Respiratory Compensation Point (RCP), Isocapnic area Time (Time-IC), Isocapnic area oxygen consumption (VO2-IC) and Time-HHV, were measured.
Resulting data indicated that TTE increased significantly in PRO and PRO+CAS compared to baseline and significantly increased in PRO+CAS compared to PLA after intervention; VT1 significantly increased in PRO and PRO+CAS compared to baseline; RCP was significantly higher than the baseline in PRO, CAS and PRO+CAS and there was a significant increase in PRO+CAS compared to PLA after intervention; VO2-IC increased significantly in CAS and PRO+CAS compared to baseline; Time-HHV significantly improved in PRO+CAS compared to baseline; also, there was a significant increase in CAS and PRO+CAS compared to PLA after the intervention.
"The findings showed that consuming probiotics and casein could relatively improve the aerobic capacity of male soccer players," The authors concluded. "Nevertheless, simultaneous consumption of probiotics and casein had a more pronounced effect on aerobic capacity indicators, especially TTE and Time-HHV."
Mechanistically, probiotics impact aerobic fitness by positively altering the fat profile and C-reactive protein (CRP) in athletes, they reported. During high-intensity exercises, the concentration of hydrogen ions and lactate increases considerably, which leads to acidification in muscles and subsequent fatigue. Probiotic supplementation reduces blood lactate levels and increases oxygen consumption. Furthermore, it enhances angiogenesis, mitochondrial biogenesis, and amino acid absorption. Casein protein is a slow-absorbing protein, which accelerates the muscle recovery speed of soccer players, thereby, delaying fatigue and improving endurance.
Journal: Journal of the International Society of Sports Nutrition
“The effect of probiotics and casein supplementation on aerobic capacity parameters of male soccer players”
doi: 10.1080/15502783.2024.2382165
Authors: Babak Imanian et al.