Rural children used to animals have ‘better immune systems’

Children raised away from cities and exposed to animals grow up to have more resilient immune systems, says a new study. They might also be at lower risk of developing mental health problems later in life.

Researchers at the University of Ulm in Germany led the study which found that animals and bacterial dust found in the countryside could help youngsters avoid health issues.

The project involved 40 healthy men aged 20-40, half of whom had grown up on a farm with animals, and half in a large city without pets. Participants were asked to give a speech in front of a group, and then solve a difficult maths problem while being timed.

Beneficial

Professor Christopher Lowry, co-author of the study, said: “It has already been very well documented that exposure to pets and rural environments during development is beneficial in terms of reducing risk of asthma and allergies later in life.

“This study moves the conversation forward by showing for the first time in humans that these same exposures are likely to be important for mental health.”

Blood and saliva were taken five minutes before and five, 15, 60, 90 and 120 minutes after the test. Results revealed that participants who grew up in cities had higher levels of immune system components called peripheral blood mononuclear cells after the stressful experience. They also had higher levels of the inflammatory compound interleukin 6 and muted activation of the anti-inflammatory compound interleukin 10.

Immune response

“People who grew up in an urban environment had a much-exaggerated induction of the inflammatory immune response to the stressor, and it persisted throughout the two-hour period,” added Prof Lowry.

Professor Stefan Reber, Head of the Laboratory for Molecular Psychosomatics at the University Clinic for Psychosomatic Medicine and Psychotherapy in Ulm, said rural residents who had had close contact to farm animals could deal with stress much better than city dwellers who had grown up without pets. This is due to help from small microbial ‘helpers’.

“These are environmental bacteria with which humans have been co-existing relatively peacefully for thousands of years and which are having a hard time in cities nowadays,” said Prof Reber, who worked with researchers in Erlangen, London and Boulder in Colorado.