Probiotics consumption may have advantageous effects on mental health by lessening the psychological symptoms of perceived stress, depression and anxiety, according to a new systematic review and meta-analysis.
Published in The Journal of Alternative and Complementary Medicine, the study reviewed the results of seven previous studies which tested for symptoms in over 300 healthy volunteers both before and after supplementation with a probiotic.
Researchers from Griffith University in Queensland, Australia, wrote: “Interest in the gut–brain axis and emerging evidence that the intestinal microbiota can influence central nervous system function has led to the hypothesis that probiotic supplementation can have a positive effect on mood and psychological symptoms such as depression and anxiety.
“Although several human clinical trials have investigated this, results have been inconsistent. Therefore, a systematic review and meta-analytic approach was chosen to examine if probiotic consumption has an effect on psychological symptoms.”
Studies published before July 2016 that were randomized and placebo controlled, and measured preclinical psychological symptoms of depression, anxiety, and perceived stress in healthy volunteers pre and post supplementation with a probiotic were included.
Seven studies met the inclusion criteria and provided data for nine comparisons.
“The meta-analysis showed that supplementation with probiotics resulted in a statistically significant improvement in psychological symptoms (standardized mean difference 0.34; 95% confidence interval 0.07–0.61, Z=2.49) compared with placebo,” they wrote.
“These results show that probiotic consumption may have a positive effect on psychological symptoms of depression, anxiety, and perceived stress in healthy human volunteers.”
According to lead author Dr Natalie Colson, more studies need to be conducted to determine if the consumption of probiotics could also assist with symptoms of diagnosed clinical depression.
“The research into the relationship between the gut and the brain is reasonably new however we are now starting to better understand this ‘gut brain axis’.
“We don’t know yet how far this could be used in the treatment of depression, however the gut microbiome presents as a potential target for the treatment of cognitive and mood disorders.
“But it does appear that generally healthy people who are going through stressful periods could certainly benefit from adding probiotics to their diet.”
Further studies may allow for the development of novel probiotic treatment strategies for gastrointestinal-related disorders that are associated with impaired communication between the gut and brain, said Dr Colson.