How Gut Bugs Affect MetabolismFriday, May 10, 2013
Novel insights into exactly how gut bugs may influence metabolism come from a study by Kimura and colleagues from Kyoto University published in Nature Communications.
In their studies in mice, they demonstrated that metabolic effects of gut bugs may be mediated by the production of short-chain fatty acids, which in turn affect energy homeostasis by interacting with the GPR43 receptor in adipose tissue, the activation of which suppresses insulin signalling and fat accumulation in adipose tissue.
Thus, they demonstrated that mice lacking the GPR43 receptor gain weight on a normal diet, while animals overexpressing this receptor appear obesity resistant even when fed a high-fat diet.
Support for the role of gut bugs comes from the fact that mice held in germ-free environments or treated with antibiotics appear completely ‘normal’.
As the authors note,
“These findings establish GPR43 as a sensor for excessive dietary energy, thereby controlling body energy utilization while maintaining metabolic homoeostasis.”
Clearly with regard to the role of gut bugs in obesity – the plot thickens.
Kimura I, Ozawa K, Inoue D, Imamura T, Kimura K, Maeda T, Terasawa K, Kashihara D, Hirano K, Tani T, Takahashi T, Miyauchi S, Shioi G, Inoue H, & Tsujimoto G (2013). The gut microbiota suppresses insulin-mediated fat accumulation via the short-chain fatty acid receptor GPR43. Nature communications, 4 PMID: 23652017