Natural immunity: biodiversity loss and inflammatory diseases are two global megatrends that might be related.

We are witnessing two global and deeply worrying trends that, at first glance, seem unrelated. The first trend is the ongoing decline in biodiversity, which is caused by human actions. It could well become the sixth mass extinction of animal and plant species on Earth, comparable in magnitude with the fifth mass extinction at the end of the Cretaceous, 65 million years ago. The second trend is a rapid increase in chronic diseases that are associated with inflammation, especially in developed countries. Inflammation is a key attribute in asthma and allergic diseases, autoimmune diseases and many cancers; even depression has been associated with the presence of inflammatory markers.

In this article, we argue that these two phenomena are more closely related than commonly thought: declining biodiversity might actually increase the risk to humanity from chronic diseases and thereby cause a major public health problem.