A review on the role of biodiversity in human health
The western world has witnessed a rising epidemic of chronic inflammatory disorders, such as allergies and asthma. Adoption of western lifestyles is expected to spread this epidemic also to the rest of the world, where allergies have been practically absent. In parallel, biological diversity is globally declining. This inspired Ilkka Hanski, together with medical doctors, to formulate the biodiversity hypothesis of allergic disease. This hypothesis proposes that reduced contact with natural environments, including natural microbial diversity, is associated with unhealthy human microbiota—which is less able to educate the immune system. Contact with beneficial bacteria, particularly early on in life, seems to be instrumental to the normal development of immune responses. Changes in lifestyle and diet, destruction of natural environments, and urbanisation threaten our natural exposure to these beneficial bacteria and thus also their impact on our physiology. To ensure a healthy life, we need to preserve biodiversity in the environment and make sure it finds a favourable home in us. In this review, we will focus on the role of commensal microbiota in human health and wellbeing, as well as the interaction between our microbiota and environmental microbiota, highlighting the contribution of Ilkka Hanski.
We (humans) are protected by two nested layers of biodiversity, consisting of bacteria (and other micro-organisms) residing in our bodies (both on the external and internal surfaces) and the one surrounding us in our living environment. The diversity and composition of the inner layer is dependent on microbial colonisation from the outer layer; a process that is under the influence of our behaviour, lifestyle, environmental management, land-use planning, etc. Read more here.
