Probiotic Lactobacillus plantarum P8 alleviated stress and anxiety while enhancing memory and cognition in stressed adults: A randomised, double-blind, placebo-controlled study

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#adult #anxiety #cognition #cytokines #double-blind-method

Probiotic Lactobacillus plantarum P8 alleviated stress and anxiety while enhancing memory and cognition in stressed adults: A randomised, double-blind, placebo-controlled study

Lew et al., 2019 | Clin Nutr | Rct

Citation

Lew Lee-Ching, Hor Yan-Yan, ... Liong Min-Tze. 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. doi:10.1016/j.clnu.2018.09.010

Abstract

BACKGROUND & AIMS: To investigate the effects of probiotic in alleviation of stress in stressed adults, along our focus to identify and justify strain specificity on selected health benefits with a precisely targeted population. METHODS: This 12-weeks randomized, double-blind and placebo-controlled study investigated the effects of a probiotic (Lactobacillus plantarum P8; 10 log CFU daily) on psychological, memory and cognition parameters in one hundred and three (P8 n = 52, placebo n = 51) stressed adults with mean age of 31.7 ± 11.1 years old. All subjects fulfilled the criteria of moderate stress upon diagnosis using the PSS-10 questionnaire. RESULTS: At the end of study, subjects on P8 showed reduced scores of stress (mean difference 2.94; 95% CI 0.08 to 5.73; P = 0.048), anxiety (mean difference 2.82; 95% CI 0.35 to 5.30; P = 0.031) and total score (mean difference 8.04; 95% CI 0.73 to 15.30; P = 0.041) as compared to placebo after 4-weeks, as assessed by the DASS-42 questionnaire. Although plasma cortisol levels were only marginally different between placebo and P8 (mean difference 3.28 ug/dl; 95% CI -7.09 to 0.52; P = 0.090), pro-inflammatory cytokines such as IFN-γ (mean difference 8.07 pg/ml; 95% CI -11.2 to -4.93; P < 0.001) and TNF-α (mean difference 1.52 pg/ml; 95% CI -2.14 to -0.89; P < 0.001) showed higher reduction as compared to placebo over 12-weeks. These were accompanied by enhanced memory and cognitive traits such as social emotional cognition and verbal learning and memory upon administration of P8 as compared to the placebo, with different effects in women as compared to men. CONCLUSIONS: The present data illustrated that L. plantarum P8 is a feasible and natural intervention for the alleviation of selected stress, anxiety, memory and cognitive symptoms in stressed adults. TRIAL REGISTRATION: Approved by the JEPeM-USM Review Panel on Clinical Studies (Approval number USM/JEPeM/16050195) and was registered at ClinicalTrials.gov (identifier number NCT03268447).

Key Findings

At the end of study, subjects on P8 showed reduced scores of stress (mean difference 2.94; 95% CI 0.08 to 5.73; P = 0.048), anxiety (mean difference 2.82; 95% CI 0.35 to 5.30; P = 0.031) and total score (mean difference 8.04; 95% CI 0.73 to 15.30; P = 0.041) as compared to placebo after 4-weeks, as assessed by the DASS-42 questionnaire. Although plasma cortisol levels were only marginally different between placebo and P8 (mean difference 3.28 ug/dl; 95% CI -7.09 to 0.52; P = 0.090), pro-inflamma

Outcomes Measured

  • anxiety
  • cortisol levels
  • inflammatory markers

Population

Field Value
Population See abstract
Sample Size 52
Age Range mean age of 31.7
Condition anxiety

MeSH Terms

  • Adult
  • Anxiety
  • Cognition
  • Cytokines
  • Double-Blind Method
  • Female
  • Gastrointestinal Microbiome
  • Humans
  • Hydrocortisone
  • Lactiplantibacillus plantarum
  • Male
  • Memory
  • Middle Aged
  • Probiotics
  • Stress, Psychological
  • Young Adult

Evidence Classification

  • Level: Rct
  • Publication Types: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't
  • Vertical: probiotics-mood

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09