Though the evidence of the role of diet and the gut in the development of psychological disorders is established and growing, the majority of the research has either been epidemiological (observations of large groups of people – these do not show causality) or animals trials (show the mechanisms but might not completely translate to humans). At the end of all of these papers the authors remark that more high-quality human trials are required to draw firmer conclusions. Earlier in the year we had the publication of the SMILES Trial, a study that showed a cause and effect relationship between poor diet and depression and now a new paper provides more good evidence of the role of probiotics and the gut microbiome on mental health. Even more interesting is that this was not even the main aim of the research.
Researchers in New Zealand set up a trial to see whether giving pregnant women probiotics would affect their children’s risk of developing eczema. Eczema is an inflammatory skin condition and the gut microbiome plays an essential role in regulating inflammation. A baby’s gut microbiome is seeded at birth during its transit through the birth canal, or from skin contact after delivery by caesarean section. In the study 423 pregnant women were randomly assigned to two groups. One group received a daily supplement of a strain of bacteria called Lactobacillus rhamnosus (HN001). The other group received an identical looking/tasting placebo. The women took the supplement/placebo from the moment they enrolled until their child was born, and from birth until 6 months if the mother was breastfeeding. Information about the women’s mental state was taken at baseline (14-16 weeks pregnant), when the child was 6 months and 12 months old. They found a strong effect of the probiotic. The women who had taken the supplement (and none of the women knew whether they were taking the active supplement or the placebo) were much less likely to experience depression and anxiety after the birth of their children.
The researchers report that between 10%-15% of women experience post-partum (post-natal) depression, which can impair the development of a strong bond between mother and infant, creating psychological and physical health risks for both. Medication options for breastfeeding women are limited because of the risk that the medication would be ingested by the baby in breast milk. In addition, it is practically difficult for women to access psychological or psychosocial interventions on top of the demands of a new baby. Further, some women feel reluctant to ask for help because they feel ashamed or guilty that they should feel so unhappy following the birth of their baby. Clearly then, the development of accessible and effective treatments is essential. There are many questions still to be answered about what a probiotic treatment might look like. This trial looked at only one strain and it might be that others of a combination are important too. We also need to know how long treatment should last and what the dose should be. But this well-designed study adds to the evidence of the role and importance of gut health in mental health and of taking the health of the whole body in to consideration when looking to treat mental health problems.
Reference
Effect of Lactobacillus rhamnosus HN001 in Pregnancy on Postpartum Symptoms of Depression and Anxiety: A Randomised Double-blind Placebo-controlled Trial. DOI: 10.1016/j.ebiom.2017.09.013