Preserving Microbial Diversity
Biologist have many ways of comparing species within an ecosystem, such as diversity of foods they eat and geographical ranges they inhabit. We can also consider them based on the diversity of microbes they possess, something biologists call their microbial repertoire. For humans, we tend to differentiate on things like blood type or the less rationale, skin color. Since humans are subject to the rules of biology, the more conceptual tool of our microbial diversity may be more informative when considering our predisposition to disease and overall health. Advances in molecular techniques reveal that our modern lifestyle of overuse of antibiotics, hyper-sterile living conditions, and changing dietary habits are escalating an imbalance with our naturally selected and evolved relationship with the microbes that live on and within our bodies. The discordance often manifests as disease. Other factors including age and genetics may also influence our microbial diversity, but diet is the easiest to modify and presents the simplest route for therapeutic intervention to improve microbial diversity and thus balance within our inner ecosystem. Recent studies reveal that our collective gut microbial communities (microbial repertoire) of thousands of species and trillions of members group into predominant variants, or “enterotypes,” dominated by Bacteroides, Prevotella, and Ruminococcus. While the basis for the enterotype clustering is unknown, and appears independent of nationality, sex, age, or body mass index, hints that diet may play a casual role in the partitioning is emerging. Groups that consume a Western diet high in animal protein, fat, and processed carbohydrates tend to be dominated by taxa typical of the Bacteroides enterotype, whereas groups that consume less processed diets higher in fiber and low in animal protein are dominated by the Prevotella enterotype. It will be important now to determine if higher incidence of disease is associated with one enterotype over another. The importance of sampling and preserving microbial diversity from traditional groups in regions where the effects of globalization on diet and lifestyle are less profound will be important in determining if interventions may allow modulation of an individual’s enterotype to improve health. By collecting feces samples from genetically similar bushmen groups – but with varying dependence on Western vs. traditional foods – we may get smarter. However, worldwide diversity of microbial repertoire’s in these traditional communities is fast disappearing.
In November 2011 we spent a week among the bushmen of Botswana and Namibia collecting stool samples to characterize the impact of varying diets on the microbiota.
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