Lactobacillus plantarum DR7 alleviates stress and anxiety in adults: a randomised, double-blind, placebo-controlled study.

2019-04-19
Beneficial Microbes 10(4)
- H. Chong
- Nor Azizi Yusoff
- Y. Hor
- L. Lew
- M. Jaafar
- S. Choi
- Muhamad Saiful Bahri Yusoff
- N. Wahid
- Mohammad Farris Iman Leong Bin Abdullah
- Norzila Zakaria
- Kee-Leong Ong
- Y. Park
- M. Liong

PubMed: 30882244
DOI: 10.3920/BM2018.0135

Study Design

Type: Randomized Controlled Trial (RCT)
Sample size: n = 111
Population: Stressed adults
Methods: Randomized Controlled Trial

Highly Cited

Abstract

Probiotics have been reported to exert beneficial effects along the gut-brain axis. This randomised, double-blind and placebo-controlled human study aimed to evaluate such properties of Lactobacillus plantarum DR7 and its accompanying mechanisms in stressed adults. One hundred and eleven (n=111; DR7 n=56, placebo n=55) stressed adults were recruited based on moderate stress levels using the PSS-10 questionnaire. The consumption of DR7 (1×109 cfu/day) for 12 weeks reduced symptoms of stress (P=0.024), anxiety (P=0.001), and total psychological scores (P=0.022) as early as 8 weeks among stressed adults compared to the placebo group as assessed by the DASS-42 questionnaire. Plasma cortisol level was reduced among DR7 subjects as compared to the placebo, accompanied by reduced plasma pro-inflammatory cytokines, such as interferon-γ and transforming growth factor-α and increased plasma anti-inflammatory cytokines, such as interleukin 10 (P<0.05). DR7 better improved cognitive and memory functions in normal adults (>30 years old), such as basic attention, emotional cognition, and associate learning (P<0.05), as compared to the placebo and young adults (<30 years old). The administration of DR7 enhanced the serotonin pathway, as observed by lowered expressions of plasma dopamine β-hydroxylase (DBH), tyrosine hydroxylase (TH), indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase accompanied by increased expressions of tryptophan hydroxylase-2 and 5-hydroxytryptamine receptor-6, while stabilising the dopamine pathway as observed via stabilised expressions of TH and DBH over 12 weeks as compared to the placebo (P<0.05). Our results indicated that DR7 fulfil the requirement of a probiotic strain as per recommendation of FAO/WHO and could be applicable as a natural strategy to improve psychological functions, cognitive health and memory in stressed adults.

Keywords: DR7; anxiety; cognition; memory; serotonin; stress.

Research Insights

Lactobacillus plantarum DR7→Enhanced Serotonin Pathway Function
The administration of DR7 enhanced the serotonin pathway, as observed by lowered expressions of plasma dopamine β-hydroxylase (DBH), tyrosine hydroxylase (TH), indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase accompanied by increased expressions of tryptophan hydroxylase-2 and 5-hydroxytryptamine receptor-6.
Effect
Beneficial
Effect size
Moderate
Dose
1×10^9 cfu/day
Lactobacillus plantarum DR7→Improved Cognitive Function
DR7 better improved cognitive and memory functions in normal adults (>30 years old), such as basic attention, emotional cognition, and associate learning (P<0.05)
Effect
Beneficial
Effect size
Moderate
Dose
1×10^9 cfu/day
Lactobacillus plantarum DR7→Improved Psychological Well-being
The consumption of DR7 (1×109 cfu/day) for 12 weeks reduced total psychological scores (P=0.022)
Effect
Beneficial
Effect size
Moderate
Dose
1×10^9 cfu/day
Lactobacillus plantarum DR7→Increased Plasma Anti-inflammatory Cytokine Levels
And increased plasma anti-inflammatory cytokines, such as interleukin 10 (P<0.05)
Effect
Beneficial
Effect size
Moderate
Dose
1×10^9 cfu/day
Lactobacillus plantarum DR7→Reduced Anxiety
The consumption of DR7 (1×109 cfu/day) for 12 weeks reduced symptoms of ... anxiety (P=0.001) ... among stressed adults compared to the placebo group as assessed by the DASS-42 questionnaire.
Effect
Beneficial
Effect size
Moderate
Dose
1×10^9 cfu/day
Lactobacillus plantarum DR7→Reduced Anxiety Symptoms
The consumption of DR7 (1×109 cfu/day) for 12 weeks reduced symptoms of... anxiety (P=0.001) as early as 8 weeks among stressed adults compared to the placebo group as assessed by the DASS-42 questionnaire.
Effect
Beneficial
Effect size
Large
Dose
1×10^9 cfu/day
Lactobacillus plantarum DR7→Reduced Cortisol Levels
Plasma cortisol level was reduced among DR7 subjects as compared to the placebo, accompanied by reduced plasma pro-inflammatory cytokines...
Effect
Beneficial
Effect size
Moderate
Dose
1×10^9 cfu/day
Lactobacillus plantarum DR7→Reduced Physical Symptoms of Stress
The consumption of DR7 (1×109 cfu/day) for 12 weeks reduced symptoms of stress (P=0.024)
Effect
Beneficial
Effect size
Moderate
Dose
1×10^9 cfu/day
Lactobacillus plantarum DR7→Reduced Plasma Cortisol Levels
Plasma cortisol level was reduced among DR7 subjects as compared to the placebo
Effect
Beneficial
Effect size
Moderate
Dose
1×10^9 cfu/day
Lactobacillus plantarum DR7→Reduced Pro-Inflammatory Cytokines
Accompanied by reduced plasma pro-inflammatory cytokines, such as interferon-γ and transforming growth factor-α
Effect
Beneficial
Effect size
Moderate
Dose
1×10^9 cfu/day
Lactobacillus plantarum DR7→Reduced Stress
The consumption of DR7 (1×109 cfu/day) for 12 weeks reduced symptoms of stress (P=0.024) ... among stressed adults compared to the placebo group as assessed by the DASS-42 questionnaire.
Effect
Beneficial
Effect size
Moderate
Dose
1×10^9 cfu/day
Lactobacillus plantarum DR7→Stabilized Dopamine Pathway Function
while stabilising the dopamine pathway as observed via stabilised expressions of TH and DBH over 12 weeks as compared to the placebo (P<0.05).
Effect
Beneficial
Effect size
Moderate
Dose
1×10^9 cfu/day