Study: the genetic link between gut health and depression

Researchers at the QIMR Berghofer Medical Research Institute in Australia have identified a significant genetic link between conditions affecting gut health and depression. The finding helps explain why physical illnesses frequently occur alongside this mental health condition, according to a statement from the institute, cited by the Xinhua news agency and reported by Agerpres.

According to the cited source, physical illnesses can contribute substantially to the poor health of people with depression, who are at risk of dying up to 12 years earlier than those without the condition.

The study, published in the journal Nature Genetics, examined the genetic relationship between major depressive disorder and four categories of physical illness: cardiovascular, metabolic, gastrointestinal, and immune.

What the researchers discovered

All four categories of illness were found to be genetically linked to depression, but gastrointestinal conditions showed the strongest association. These include irritable bowel syndrome, gastro-oesophageal reflux disease, gallstones, and peptic ulcer disease.

The researchers found that the genetic risk factors involved in these physical illnesses overlap with nearly half of those associated with depression.

The role of the gut-brain axis

Damian Woodward, a doctoral candidate at QIMR Berghofer and the study's lead author, explained that the results highlight the importance of treating depression through an approach that goes beyond focusing solely on the brain.

"We found that gastrointestinal conditions had the strongest shared genetic link with depression, confirming that the gut-brain axis plays an essential role in explaining why depression so frequently occurs alongside physical conditions," said Woodward.

The researcher added: "The gut is often referred to as the 'second brain', sharing many of the same signalling chemicals and containing a large number of nerve cells." The study identified genetic factors that influence communication between the gut and the brain, which may contribute to the development of depression, gut dysfunction, and immune-related conditions.

The authors hope that these findings will help identify new treatment options, including through the repurposing of existing medications, and reduce the broader impact that depression has on overall health.