Gut feeling: Stomach bacteria could affect emotions

WE often talk of having a ‘gut feeling’ – and now it emerges there could be more truth to that than previously thought.

The bacteria in our guts are linked to our emotions and decision-making, research suggests – with some types associated with feeling more anxious.

Scientists from the University of California at Los Angeles, who analysed gut bacteria in healthy women, found that different types of bugs were linked to different areas of the brain being more active, which seemed to affect emotional reac- tions. The team, led by Dr Kirsten Tillisch, an associate professor in gastroenterology, said it is not clear whether bacteria in the gut influences the development of the brain or if the brain is influencing the types of bacteria that grow in the gut.

But they say: ‘Both possibilities, however, could lead to important changes in how one thinks about human emotions.’

The researchers, who studied 40 women aged 18 to 55, found that in 33 participants a type of germ called bacteroides was most prominent. The other seven had more of a bacteria called prevotella.

The women with more bacteroides had more activity in the frontal cortex and insula of their brains – regions involved in processing information – as well as the hippocampus, which is important for memory.

The prevotella group had more connections in brain areas involved in emotion and attention, but smaller areas devoted to memory processing. When both groups were shown negative images, such as angry faces, the group with more of the prevotella bacteria had higher levels of anxiety and irritability, the study found. The findings were published in the US journal Psychosomatic Medicine.

The research was partly funded by yoghurt firm Danone. Probiotic yoghurts, which claim to contain ‘good’ bacteria, have become popular thanks to a belief they boost health. But there has been little research into emotions and gut bacteria.