In Science this week, a group of Chinese scientists reports the discovery of a group of gut bacteria that appears to be responsible for the beneficial effects of a high-fiber diet on type 2 diabetes. By combining a randomized clinical study of people with diabetes on specifically designed isoenergetic diets with fecal shotgun metagenomics, the researchers found that the abundance of certain microbial species over others, rather than microbial diversity, more closely correlated with health-related changes in the gut microbiota. They then identified 15 strains of microbes that produce short-chain fatty acids (SCFAs) — which are generated by gut bacteria and are required for normal gut functioning — that were particularly promoted by high-fiber diets, acted together to boost SCFA production and improve health, and out-compete other microbes that hinder effective metabolism.
And in Science Advances, Chinese and Korean researchers publish a study suggesting that the higher incidence of skin diseases in urbanized areas versus rural ones may be due to the fragility and lack of diversity of skin microbiomes in city dwellers. The investigators used 16S ribosomal RNA gene amplicon sequencing to compare the skin microbiomes of 231 young, healthy women in three large cities and two megacities in China. They found that the individuals' skin microbiomes varied mainly with environment and socioeconomic status, and suggest that the differences could be explained by the predominantly niche-based assembly of microbial communities. Notably, networks among microbes in larger cities were the most fragile, which may contribute to the higher incidence of skin diseases in more urbanized environments, the authors write. "These results suggest that microbial ecological theory can provide a framework for understanding crucial health-associated features of the human microbiome," they add. GenomeWeb has more on this study, here.