Depression linked to digestive bacteria
Bacteria in the gut may affect our mental well-being and could be linked to depression, researchers said recently after conducting the largest study of its kind so far.
The World Health Organization says an estimated 300 million people suffer from depression, and there are known links between a patient’s physical and mental health.
Scientists in Belgium now believe that a wide range of gut bacteria can produce chemicals that significantly impact the brain, including several micro-organisms linked — positively or negatively — to mental health.
The experiment, known as the Flemish Gut Flora Project, examined depression data and stool samples from more than
1,000 people and found that two types of bacteria were “consistently depleted” in those who suffered from depression. This held true even if patients were on antidepressants.
Scientists’ understanding of how the gut and brain are linked is in its early stages, and the researchers acknowledged that their findings, published in the journal Nature Microbiology, could be considered controversial.
“The notion that microbial metabolites can interact with our brain — and thus behaviour and feelings — is intriguing,” said lead researcher Jeroen Raes, from the department of Microbiology and Immunology at KU Leuven University.
“Until now, most of the studies were in mice or in smallscale human studies, with mixed and contradictory results,” he said.
The team repeated the study on 1,063 people from the Netherlands and a third group of clinically depressed patients in Belgium, and got similar results.
Raes stressed, however, that while the experiment showed a clear link between the levels of certain bacteria in the gut and an individual’s mental well-being, that didn’t mean that one thing directly caused the other.
The two microbe groups, coprococcus and dialister, are know to have anti-inflammatory properties.
“We also know that neuro-inflammation is important in depression. So, our hypothesis is that somehow these two are linked,” said Raes.
Depression — a treatable but debilitating condition that affects how an individual behaves and feels — is sometimes referred to as a “silent epidemic”, and is a major driver of the
800,000 or so suicides that occur each year worldwide.