Our body hosts ten times more bacterial cells than we have body cells, and these bacteria have a collective genome that is about 150 more extensive than the human genome. We depend on these microbes in many ways, and this is especially so for the guts, which contain an ecosystem with numerous species of bacteria and other microorganisms that interact in complex ways with the host. One recent finding is that the gut ecosystem can be in contrasting states. There are globally roughly three ‘entero-types’ that could represent alternative stable states, but more subtypes appear to exist, and various diseases are associated to particular low-diversity states of the gut ecosystem. Although this ecosystem is still poorly understood, is has become clear that the state of the gut flora is linked to diseases ranging from irritable bowel syndrome and Crohn’s disease to psychiatric disorders.
With Willem de Vos, Leo Lahti and others we work on understanding what determines the stability of the alternative states, and how their resilience is affected by diet, genetics and other factors.
Tipping elements in the human intestinal ecosystem
Nature Communications 5 [Full text]