De-stress with soil

A tiny organism that lives in soil has been found to reverse some of the physical effects of stress, researchers from the University of Colorado have shown thisweek.

When we get stressed our bodies trigger an immune response, which causes a process called inflammation.

Inflammation can lead to problems with the delicate balance of bacteria in our gut, as well as affecting our brain chemistry, which can even cause depression and anxiety.

Publishing in PNAS this week, researchers from University of Colorado, USA, have found that if they inject stressed mice with a small amount of this microorganism, they can help reduce some of the symptoms of stress.

Professor Graham Rook from UCL was one of the collaborators on the project, and he explained some of the benefits to the Naked Scientists.

'It turns out that by giving this organism as an injection to these animals, when they were then exposed to a stress, they still had some changes but it blocked the development of anxiety, it blocked the development of the colitis - inflammation of the bowel, and it stabilised, to some extent, the changes that stress causes in the gut,' said Rook.

The researchers think this microorganism works by turning on 'regulatory T-cells' in the body which help regulate the immune system.

The microorganism from the soil actually increased the number and activity of these cells, as well as increasing the activity of chemicals which help reduce inflammation.

This could be particularly relevant for people in more developed countries, where there is growing evidence that our immune systems aren't turning off when we stop being stressed.

Rook believes that this is because we aren't exposed to as many microorganisms early on in life - a theory called the 'old friends' hypothesis.

'The immune system, like the brain, needs to be educated. It needs inputs. And those inputs come mostly from the microorganisms that we encounter,' said Rook.

“现在我们认为正在发生的是控制器l mechanisms that switch off the immune system when it's not required aren't being educated properly in the early years of life. And it's clear now that people living in rich western countries are not getting exactly the right inputs to their immune system.'