Studies revealing the effect of probiotics on mood have led to the terms “Psychobiotics” - probiotics that contain psychotropic properties - and "gut-brain axis", which is now a vastly researched area.
Competitive football players who undergo strenuous training and frequent competitions are more vulnerable to psychological disorders. Probiotics have been found to be capable of reducing these psychological disorders. Much of the work being done in this emerging area has been carried out on mouse models with pioneering studies to explore the association starting as recently as 2015.
The present study, published in 'Nutrients', aimed to determine the effect of daily probiotics supplementation on anxiety induced physiological parameters among competitive football players.
A collaborative team of researchers from Malaysia, Sri Lanka, and London, carried out a randomised, double-blinded, placebo-controlled trial on 20 male footballers aged 18 to 21 who received either a commercially available probiotic cultured milk (3x 10 billion CFU of Lactobacillus Casei Shirota) or a placebo drink over eight weeks.
Portable biofeedback devices were used to measure the electroencephalography, heart rate, and electrodermal responses along with cognitive tests at the baseline, week 4, and week 8.
The cognitive test reaction time showed significant improvement in the probiotic group compared to the placebo.
There was no significant difference between the probiotic and placebo groups for heart rate and electrodermal responses after eight weeks and brain waves showed no significant changes during the study period except for the theta wave and delta wave at week 4.
In conclusion, the authors say that daily probiotics supplementation may have the potential to modulate the brain waves theta (relaxation) and delta (attention) for better training, brain function, and psychological improvement to exercise. They say further research is needed to elucidate the mechanism of current findings.
The report states: "Football is a game where players need to make decisions based on a rapidly changing environment while considering teammates, opponents, as well as the ball. Due to that, players need to intensely focus their attention on the game and maintain the highest physical capabilities to achieve their targets. Stress, anxiety, and depression are often associated with competitions, and regulating these psychophysiological components can be the solution to improve performance via food-based nutritional supplements.
"Though the heart rate and electrodermal responses showed no significant changes with daily supplementation of Lactobacillus Casei Shirota strain, the delta and theta brain waves were higher in the probiotic group after four weeks that provide evidence for relaxation and attention components in the probiotic group.
"Sustained attention also showed significant improvement in the probiotic group with supplementation. As far as we know, this is the first report to clearly show the beneficial effects of probiotics supplementation on brain wave outcomes using objective EEG measures."
According to Huang et al, the gut can manipulate the brain in different ways. Probiotics secrete neurotransmitters such as gamma-aminobutyric acid (GABA), serotonin, and catecholamines, which inhibit the transmissions of the nerve impulses in the central nervous system (CNS).
Nevertheless, probiotics can regulate the dysfunctional hypothalamic–pituitary–adrenal axis (HPA axis). When an individual experience a stressful condition, the HPA axis activates and causes the adrenal glands to secrete cortisol. In inflammation, transmitters send impulses to the brain through the Vagus nerve causing psychological disorders, but probiotics have been shown to be capable of minimising the inflammation condition by improving the immune functions.
The report concludes: "The complete mechanisms of action of probiotics supplementation remain unknown. Further studies are needed to clarify the mechanisms underlying the effects of probiotics supplementation on maintaining psychology outcomes via brain waves."
Adikari, A.; Appukutty, M.; Kuan, G.
"Effects of Daily Probiotics Supplementation on Anxiety Induced Physiological Parameters among Competitive Football Players."