Why are some children more likely than others to develop asthma and allergies? A new paper* from Dr. Stuart Turvey’s group reviews what we’ve learned so far, and looks to exposome research as a path forward to understand the connections between our environments, the microbes that live inside us, and our health.
Various components of outdoor and indoor environments are known to either increase or decrease a child’s risk of developing asthma and allergies. For example, air pollution, urban versus rural environment, pesticides and herbicides, pets and other children in the home, and moldy or damp housing can all affect asthma risk. Most of the research on this topic has looked at one type of exposure at a time, but of course we all live in very complex environments, with lots of potentially harmful and protective exposures happening all at once and building up over many years. In their review paper, Dr. Hind Sbihi (a postdoctoral researcher in the Turvey lab) and her co-authors make the case that to understand how extrinsic environmental factors affect asthma risk we should think about the exposome as a whole - and also go “under the skin” to look at the microbes that live inside our bodies.
Every human being is an ecosystem, hosting complex communities of bacteria, fungi, and viruses (collectively called microbiomes) on our skin and in the organs inside our bodies. It’s being increasingly recognized that the composition of these microbiomes can have wide-reaching impacts on human development and health. For example, children with imbalances in their gut microbiomes are more likely to develop asthma and/or allergies. The composition of internal microbiomes can be affected by external factors, such as the types of microbes we encounter in our food and water; on the surfaces we touch and the air we breathe. Antibiotics and other drugs, and potentially other chemicals in the environment, can also affect microbiomes.
“In this review we argue that the field must ‘think bigger’ and that an exposome perspective integrating internal and external microbiomes with environmental factors can provide a more comprehensive framework to define how environmental exposures can shape the gut microbiome and influence the development of allergic disease”, says Dr. Sbihi.
In other words, can the presence of different types of microbes in damp versus dry housing, or in cities versus forests or fields, affect asthma risk by modifying the gut microbiome? Can chemicals such as traffic fumes and pesticides affect the microbes that live within us? Looking at how external microbiomes and other exposures affect internal microbiomes can help us to understand how children’s exposomes contribute to their overall risk of developing asthma, allergy, and other disorders.
Watch this space for updates on future exposome research papers from our investigators!
*"Thinking bigger: How early life environmental exposures shape the gut microbiome and influence the development of asthma and allergic disease". Hind Sbihi, Rozlyn CT. Boutin, Chelsea Cutler, Mandy Suen, B. Brett Finlay, Stuart E. Turvey. Allergy. 2019: doi: 10.1111/all.13812
article by Dr. Cath Ennis