Childhood Asthma The Farm Effect
Many children suffer from asthma or allergies. Early and effective prevention of these diseases is the declared goal of science. Which research strategies do scientists pursue and what part does cow barn play in this story?
Cough, shortness of breath, respiratory distress - up to ten percent of all children are affected by asthma symptoms in the course of their childhood years. Besides genetic factors, the environment in which children grow up plays a major role. Current allergy research targets the early development of asthma and allergies in the very young - with the aim of preventing the onset of the diseases.
One prominent lead that current research on allergy prevention is pursuing is the so-called hygiene hypothesis, which suggests that exposure to microorganisms early in life may be protective against asthma and allergies. Equally prominent is Erika von Mutius, director of the Institute for Asthma and Allergy Prevention at Helmholtz Munich, ((LINK to PI page)). She is one of the world's leading proponents of the hygiene hypothesis. She came up with this hypothesis after allergies had increased sharply in recent decades in industrialized countries, especially among city dwellers. So is it all a question of the living space?
Studies show that children growing up on a farm environment are significantly less likely to develop asthma or other allergies than children not living on a farm. However, it is not the rural environment that is relevant. In extended studies, Erika von Mutius discovered that spending time in a cow barn or drinking raw cow's milk plays a major role in protecting children from the diseases.
Further studies reveal that microorganisms such as bacteria, fungi or worms seem to have a protective effect against allergies. However, and this may disappoint many children - it cannot be confirmed that less hygiene in the household protects against allergies.
Why are farm children better protected against asthma? Let's take a journey to the origins of the immune system: From birth, we are exposed to an environment full of small organisms. They start challenging our immune system in the very first minutes of our lives. The most important player is our gut. Here, the gut microbiome, a community of many microorganisms, starts to mature in the first years of life. The more diverse the microbiome becomes, the more it helps to protect us from asthma. Farm children are therefore particularly well protected: Life on a farm promotes the maturation of their gut microbiome.
Many reasons support the idea of a communication axis between the gut, immune system and lungs: Indeed, children with mature gut microbiomes also have high levels of short-chain fatty acids in the gut, which protect them from disease.
How can this knowledge from research be transferred into practice? How can children with a family background of increased risk for asthma benefit even if they don't have the chance to grow up in a farming environment? Scientists at Helmholtz Munich are searching for active substances that imitate the effects of nature and stimulate the early maturation of the immune system. A mature immune system is more tolerant towards the environment and less likely to develop allergy to pollen. A number of active substances are currently in development providing hope for affected children and their families.
In 2013, Erika von Mutius was awarded the Leibniz Prize of the German Research Foundation for her finding that children growing up in rural areas and in contact with farm animals have a lower risk of developing allergies. She continues to decipher the cellular and molecular mechanisms behind this observation: "Our strategy focuses on very early prevention, as early as the first year of life, when the gut microbiome can still be easily influenced. We already know that it is not a single bacterium alone that protects against asthma, it is rather the gut microbiome as a whole. So we need to think in completely new ways for effective prevention."
The studies on farm children have consistently shown that children who regularly drink raw milk are better protected against asthma, allergies and respiratory infections. As raw milk may contain pathogens, this observation cannot be directly transferred into clinical practice to prevent asthma and allergies. Studies are now ongoing to test minimally treated cow's milk, in which the beneficial properties of raw milk are largely retained but germs of concern have been removed.
Erika von Mutius hopes that the studies will show that this type of processed cow's milk can be used to prevent the development of asthma and allergies in children in the future. In order to take a next step towards the big goal - a world without asthma.