Study Shows Yoghurt Can Help Depression

March 15, 2017

Not only can we improve our mood with food, researchers believe yoghurt may be able to help depression. In the new study, researchers from the University of Virginia School of Medicine found that feeding yoghurt - or the live bacteria found in yoghurt, lactobacillus - to mice with “depressive-like behaviour” or “despair behaviour,” reversed their symptoms. As research into the gut/brain axis grows, evidence shows that what we eat can influence our mood and mental health by changing the balance of bacteria in our bellies. Additionally, research has found that a poor diet is a risk factor for depression. Based on this understanding the researchers of the new study, published in Scientific Reports, looked to the microbiome to explore its link with depression. “Depressive disorders often run in families, which, in addition to the genetic component, may point to the microbiome as a causative agent,” they said. “In chronically stressed mice displaying despair behaviour, we found that the microbiota composition and the metabolic signature dramatically change. Specifically, we observed reduced lactobacillus and increased circulating kynurenine levels [a metabolite in the blood known to drive depression] as the most prominent changes in stressed mice.” So they fed these mice lactobacillus and found it was enough to “improve the metabolic alterations and behavioral abnormalities”. “The big hope for this kind of research is that we won’t need to bother with complex drugs and side effects when we can just play with the microbiome,” explained lead researcher Alban Gaultier. “It would be magical just to change your diet, to change the bacteria you take, and fix your health - and your mood.” He added: “A single strain of Lactobacillus is able to influence mood.” Nearly half of all Australians will experience a health condition in their lifetime and, worldwide, more than 300 million people suffer from depression. It is the leading cause of disability worldwide, according to the World Health Organisation. If we could cure that with yoghurt it would indeed be magical. Dr Paul Bertrand, a senior lecturer at RMIT University and an expert on the neuronal control of the gut, finds the research interesting but says it hasn’t “gone that extra step” to show the human connection. “The lactobacillus isn’t magical - it changes metabolism which changes production of other metabolites which hopefully gets the brain to change brain chemistry,” explains Bertrand. It does however add to understanding about the different mechanisms behind depression. “The older theory is that it’s just an imbalance - that dopamine or serotonin in the brain is unbalanced and if you change that balance with Prozac for instance - antidepressants - you can bring things back into balance,” he says. Now, however it is understood that there are multiple possible causes including learned depression - like post-traumatic stress which changes the connections in the brain - or brain inflammation, which may be driven by changes in the microbiota. We can change the microbiota by what we eat - fibre or yoghurt or the mediterranean diet (which some research has suggested may help to alleviate depression) - as well as our bowel movements. The stressed mice in the new study were constipated, Bertrand explains. “That’s well known to be a huge changer of the microbiota,” Bertrand says. “Stress isn’t changing the microbiota, it’s changing how the gut reacts… The reason was there was change in the microbiota that there was a change in transit time in the colon.” It’s the same with diarrhoea. For instance, if we get a bout of gastro, it can change the balance of our microbiome - potentially enough to cause depression - because our gut bacteria (good and bad) are stored in the colon. “You have all these risk factors - genetics and life experiences and things like that and it sometimes doesn’t take much to push people into a first episode,” Bertrand says. “If something was to cause a depletion of your tryptophan [an amino acid that converts to serotonin] or unbalance your serotonin that could trigger a first depressive episode.” So can we cure such an imbalance with yoghurt, as the study suggests? In all likelihood, it depends on the cause of depression, but Bertrand warns against trivialising or reducing depression to something that can be simply fixed with food. “I think everybody should eat yoghurt, but if you are depressed and you try and eat yoghurt and it’s not working it’s not because there’s something wrong,” Bertrand says. “It’s just yoghurt doesn’t work for you. Everyone is different, everyone has different microbiota and some things work better than others for some people. “I think treatments for depression are always going to be multi-pronged. Depression is very complex and diet is certainly going to play a role… there’s no one therapeutic diet you can pop everyone on. “Maybe it does help some people and there’s certainly nothing wrong with trying it .”