Competitive football players who undergo strenuous training and frequent competitions are more vulnerable to psychological disorders. Probiotics are capable of reducing these psychological disorders. The present study aimed to determine the effect of daily probiotics supplementation on anxiety induced physiological parameters among competitive football players. The randomized, double-blinded, placebo-controlled trial was conducted on 20 male footballers who received either probiotics (Lactobacillus Casei Shirota strain 3 × 1010 colony forming units (CFU) 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. Data were statistically analyzed using mixed factorial ANOVA and results revealed that there is no significant difference between the probiotic and placebo groups for heart rate (61.90 bpm ± 5.84 vs. 67.67 bpm ± 8.42, p = 0.09) and electrodermal responses (0.27 µS ± 0.19 vs. 0.41 µS ± 0.12, p = 0.07) after eight weeks. Similarly, brain waves showed no significant changes during the study period except for the theta wave and delta wave at week 4 (p < 0.05). The cognitive test reaction time (digit vigilance test) showed significant improvement in the probiotic group compared to the placebo (p < 0.05). In conclusion, these findings suggest that daily probiotics supplementation may have the potential to modulate the brain waves namely, theta (relaxation) and delta (attention) for better training, brain function, and psychological improvement to exercise. Further research is needed to elucidate the mechanism of current findings.

Background: Reports of probiotic consumption on athletes’ performance are debatable due to their equivocal results. There is a need for more evidence on the effects of probiotic intake on psychological state and fitness level. Thus, this study determined the effects of daily probiotic consumption on competitive anxiety, perceived stress and mood among university badminton players, besides their fitness like aerobic capacity, strength, speed, leg power and agility. Methods: Thirty university badminton players aged from 19 to 22 years old were randomly divided equally into two groups, where the probiotic group (PG; n = 15) received a drink that contained Lactobacillus casei Shirota (3 × 1010 CFU) and placebo group (CG; n = 15) a placebo drink for six weeks. Anxiety, stress and mood levels were determined using the CSAI-2R, PSS and BRUMS questionnaires, respectively. Fitness levels were measured using by subjecting the players to 20-m shuttle runs (aerobic capacity), handgrips (muscular strength), vertical jumps (leg power), 40-m dash (speed) and T-test (agility). The Student’s t-test (p < 0.05) was used to determine the differences between PG and CG players. Results: After six weeks, the anxiety and stress levels of PG players significantly decreased by 16% (p < 0.001) and 20% (p < 0.001), respectively, but there were no significant changes detected in CG players. Supplementation of probiotics also improved aerobic capacity in PG players by 5.9% (p < 0.001) but did not influence the speed, strength, leg power and agility. Conclusions: Probiotics supplementation showed improved aerobic capacity and relieve anxiety and stress. However, further studies need to be carried out to determine the mechanisms through which probiotic intake produces these effects.

Psychobiotics derived from probiotics which contain psychotropic properties, and with correct administration can positively affect the psychological states. Athletes who go through strenuous training are more vulnerable to undergo stress and anxiety. Thus, the objective of this study is to determine the effect of daily probiotics supplementation on stress and anxiety among the football players. The randomised, doubleblinded, placebo-controlled trial was conducted using 20 male footballers (age 19.0 ± 0.72 years) who received either probiotic (Lactobacillus Casei Shirota 1×10 9 CFU strain) or placebo supplement over 8 weeks. Competitive state anxiety and perceived stress were measured at the baseline, week 4, and week 8 during the intervention. Statistical analysis using t-test revealed that probiotic group significantly decreased the cognitive state anxiety scores (18.20 ± 3.94 vs. 23.11 ± 4.81, p = 0.026), somatic state anxiety (13.00 ± 2.83 vs.16.78 ± 3.03, p = 0.012) and perceived stress scores (12.30 ± 1.70 vs. 14.67 ± 1.66, p = 0.007) but no statistical significant was found in self-confidence (34.80 ± 3.16 vs. 32.89 ± 3.62, p = 0.236). Therefore, daily probiotic supplementation is a promising approach to regulate stress and anxiety among football players and it may indirectly improve athletic performances.

Background: Even though psychological disorders can be treated with various methods, one of the emerging concepts is psychobiotics. Psychobiotics are the probiotics that have psychotropic properties in it, and these probiotics proved with the proper administration could provide physiological and psychological benefits to healthy individuals. In past years, many interventions have been conducted to identify these effects using human and animal samples. Thus, the objective of this review is to summarise current human studies conducted to investigate the effect of probiotics on psychological conditions Materials and Methods: A literature search was conducted using different databases includes Scopus, Pub Med, Web of Science, Science direct, and Google scholar referring to the past 15 years. 526 studies have been extracted and after removing duplicates and studies that do not meet the inclusion criteria, twenty-two studies were selected to document in the present review from 2004 to 2018. Result: Majority of these studies have revealed the effect of probiotics for improving the psychological disorders such as anxiety, stress, and depression with the significant difference between experiment and placebo groups. Thus, some studies showed no significant difference between groups. This may be due to different dosages, probiotic strains, intervention duration used in the studies. Conclusion: Daily probiotic supplementation can positively affect psychological conditions among different populations.