by Eleanor Parkyn
Bacteria that can be found in probiotic live-culture yoghurts has been discovered to reverse symptoms of depression in mice. The bacteria, Lactobacillus, can reveal a direct link between the health of the microbiome found in the gut and our mood and mental health. Alban Gaultier, the researcher responsible for discovering this revolutionary link is hopeful that this breakthrough will lead to obsoleting drugs designed to alter mood, instead relying on dietary changes, which incorporate more of the probiotic bacteria to aid the balancing of the mood.
Depression is one of the most common mental health issues in the UK, with the Office for National Statistics revealing that almost a fifth of adults suffer from the illness. While many of us will have experienced some form of depressive episode, for those diagnosed with depression as a mental health condition, medication is often required. Medication for mental health issues such as depression usually come hand-in-hand with some pretty awful side effects; some of which can make feelings of anxiety or suicidal thoughts more extreme rather than ease them. Therefore, it is crucial for alternatives to be discovered for treating depression, so that these side effects can be avoided while maintaining good mental health.
The researchers from the University of Virginia School of Medicine were already aware of the link between stress and depression; in that those who are more stressed are more likely to develop depression. Gaultier and his team used this to test ideas of the microbiomes relationship with depression, but analyzing the composition of the microbiome in mice before and after they were subjected to stress. The major change noted in the mice that were stressed was the disappearance of Lactobacillus. Mice that lost these bacteria developed symptoms of depression, yet were returned to a normal mood when replenished with Lactobacillus; revealing a connection between an unbalance of the gut microbiome and an unbalance of the mental state.
Depression and this lack of Lactobacillus are linked via a metabolite in our blood called kynurenine, which has previously been shown to increase symptoms of depression. The levels of this metabolite grew the more the Lactobacillus was reduced.
Obviously a mouse isn’t going to tell us it’s sad and get diagnosed with depression; instead Gaultier had to observe for ‘depressive-like behavior’, which is considered the best alternative when studying depression in non-human life. So we cannot rejoice and chuck our anti-depressant meds in the bin just yet, as human studies have yet to commence, but the team behind this discovery already have plans to examine the effects of Lactobacillus on human subjects, and are hopeful that the effects will be the same; as the biological substances and mechanisms that levels of the bacteria affect can be located in both mice and humans.