Recent studies have suggested a possible effect of probiotics on stress and cognitive function. The aim of this randomized, double-blinded and placebo-controlled was to examine the effects of L. plantarum P8 in stressed adults. The authors examined the effects of the supplementation (10 log CFU/day, for 12 weeks) on stress, anxiety, memory and cognition parameters.

103 stressed adults have been enrolled. Results of the DASS-42 questionnaire after 4 weeks showed a beneficial effect of L. plantarum on score of stress (mean difference = 2.94, 95% CI: 0.08 to 5.73, p = 0.048), anxiety (MD = 2.82, 95% CI: 0.35 to 5.30, p = 0.031) and total score (MD = 8.04, 95% CI: 0.73 to 15.30, p = 0.041). No significant effect on the supplementation on cortisol levels has been measured. In addition, enhanced memory and cognitive traits have been noted in the supplemented group in comparison to placebo.

Therefore, these results suggest that L. plantarum P8 can reduce stress and anxiety in stressed adults, while improving memory and cognitive function.

Lew LC, Hor YY, Yusoff NAA, Choi SB, Yusoff MSB, Roslan NS, Ahmad A, Mohammad JAM, Abdullah MFIL, Zakaria N, Wahid N, Sun Z, Kwok LY, Zhang H, Liong MT. Probiotic Lactobacillus plantarum P8 alleviated stress and anxiety while enhancing memory and cognition in stressed adults: A randomised, double-blind, placebo-controlled study. Clin Nutr. 2019 Oct;38(5):2053-2064.