Enterotypes & the full microbiome picture

Each person’s precise microbiome composition is unique, which is why we refer to our service as personalised microbiome profiling. In early studies of large cohorts of people, the idea emerged that several broad classes of microbiome compositions could be identified, called “enterotype”.

Each enterotype was distinguished by a particular dominant bacterial type. For example, the mostly widely recognised enterotypes were those in which either Bacteroides, Prevotella or Firmicutes are the most abundant bacteria.

Importantly, each enterotype was thought to confer distinct functions on our guts. Prevotella-dominant microbiomes were associated with individuals with diets rich in fibre (typically, a non-Western diet). These bacteria are particularly adept at breaking down plant fibres, but relatively poor at digesting fats and proteins. Bacteroides-dominant microbiomes were associated with people with diets rich in animal proteins and saturated fats and these bacteria are specialised at breaking down animal-derived carbohydrates, and are rich in carbohydrate digestion in general.

Currently, it is thought that describing microbiomes as distinct enterotypes is an oversimplification of a much more dynamic situation. While each of our guts will have different amounts of the various bacteria, comparing between us we are much more likely to see variation along a spectrum of compositions. While this makes analysing and interpreting microbiome data much more difficult, it does highlight the need to consider each person’s microbiome as a unique entity.

Also important to the functioning of our gut microbiome is its bacterial diversity. A rich assortment of bacteria is associated with a healthy functioning gut. Whereas in gut disease, a decrease in the level of diversity is observed. While changes in diversity will alter the presence and absence of specific bacteria, it is probable that a richly diverse microbiome is more resistant to perturbations caused by environmental factors (including diet or illness) and thus less likely to suffer dysbiosis. This also emphasises the need to consider the full microbiome rather than try to identify just the dominant bacteria.

Read more here: Knights et al. Rethinking Enterotypes. Cell Host Microbe. 2014 Oct 8; 16(4): 433–437.