Saturday, 26 July 2014

Linking gut microbiota to obesity

The human gut microbiome is influenced by many factors, such as antibiotic usage, disease status, seasonal changes, and aging. In recent years, diet has emerged as one of the most important factors believed to affect the composition and activity of the gut microbiome. A recent article published in Nature reported that diet "rapidly and reproducibly alters the human gut microbiome." (2014, Nature 505, 559.) 

The abstract to this interesting paper reads:

“Long-term dietary intake influences the structure and activity of the trillions of microorganisms residing in the human gut but it remains unclear how rapidly and reproducibly the human gut microbiome responds to short-term macronutrient change. Here we show that the short-term consumption of diets composed entirely of animal or plant products alters microbial community structure and overwhelms inter-individual differences in microbial gene expression. The animal-based diet increased the abundance of bile-tolerant microorganisms (Alistipes, Bilophila and Bacteroides) and decreased the levels of Firmicutes that metabolize dietary plant polysaccharides (Roseburia, Eubacterium rectale and Ruminococcus bromii). Microbial activity mirrored differences between herbivorous and carnivorous mammals2, reflecting trade-offs between carbohydrate and protein fermentation. Foodborne microbes from both diets transiently colonized the gut, including bacteria, fungi and even viruses. Finally, increases in the abundance and activity of Bilophila wadsworthia on the animal-based diet support a link between dietary fat, bile acids and the outgrowth of microorganisms capable of triggering inflammatory bowel disease. In concert, these results demonstrate that the gut microbiome can rapidly respond to altered diet, potentially facilitating the diversity of human dietary lifestyles.”

Posted by Tim Sandle

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