Human Gut Bacteroidetes

The human large bowel is colonized by a community of microbes, the microbiota, which has a significant impact on human health and nutrition through the production of short chain fatty acids (SCFAs), and by interaction with the host immune system. The major nutrients available to these organisms are dietary glycans, also known as complex carbohydrates. Thus, dietary and nutraceutical strategies, based on complex carbohydrates, can, potentially, be deployed to encourage the dominance of beneficial microbes in the microbiota, particularly those producing health promoting SCFAs such as propionate and butyrate, and bacteria that have an anti‐inflammatory impact through its interaction with the human immune system, ensuring that this microbial ecosystem has a positive influence on human health. This approach, however, is greatly restricted by a critical lack of understanding of the mechanisms by which complex glycans are metabolized by the microbiota. Significantly, the wealth of genomic and metagenomic microbiota sequence presents an exciting, but so far unfulfilled, opportunity to make decisive advances in our understanding of glycan metabolism in the human large bowel. This seminar will review our biochemical, genetic and microbiological strategies, in harness with metagenomic and genomic data, to understand the mechanisms of complex glycans utilization by the human microbiota1,2,3. The models established, will trigger the development of novel dietary strategies that are designed to maximize human health through manipulation of microbiota structure.