August 14, 2014

expert reaction to disruption of gut bacteria in early life and obesity in adulthood in mice

A mouse study in the journal Cell reported that certain microbes in the gut shape metabolism very early in life and that disrupting them with antibiotics during infancy caused metabolic changes that appeared to increase the risk of obesity for adult mice.

Mr John FitzGerald, RUMA Secretary General (Responsible Use of Medicines in Agriculture Alliance), said:

“Reference is made in the paper and the press release to farmers exposing livestock to low doses of antibiotics to promote growth for decades.  This is an unhelpful comparison to make, because antibiotic growth promoters, which have been banned in the EU since 2006, are not about making livestock fat but rather can increase lean mass. So growth promotion in livestock and obesity in mice are different things. The important reported observation is the apparent effect on mouse response to a high fat diet where prior antibiotic exposure may potentiate obesity.”

Prof Naveed Sattar, Professor of Metabolic Medicine, University of Glasgow, said:

“This is an impressive study testing the theory of gut bacteria altering the body’s metabolism.  The results suggest that early antibiotics in newborn mice may lead to more obesity in later life by altering aspects of immune function.   However, one must remember the study was conducted in mice, so that results in humans cannot be inferred to be similar and may be entirely different.  Future studies relating early antibiotic use in babies to later health will help test translation of these findings to humans but proving a direct cause and effect in will be difficult.   For now, whilst the results are of interest, they cannot alter any current clinical practice.  Antibiotics in children or newborns should be given on the basis of clinical needs, whereas the usual advice about lifestyle remains the most important means to tackle obesity.”

Professor Nigel Brown, President, Society for General Microbiology, said:

“This is an interesting study that adds to the evidence that the gut microbiome may play an important role in human health and development. As the authors state, farmers have known for some time that low-level doses of antibiotics can be used to alter the gut microbiome and promote growth in farm animals. Whether the effects described in this paper for mice are applicable to humans is currently unknown, but it remains important that antibiotics are only given to patients when appropriate.”

Prof Jodi Lindsay, Professor in Microbial Pathogenesis, St George’s, University of London, said:

“This paper presents the strongest evidence so far that antibiotics in early life can predispose to obesity.  Even though the studies were performed in mice, they provide a likely explanation for why antibiotic use in children can be associated with obesity.  Further research in humans is now needed, and in particular to understand whether antibiotics are more or less important than diet and other factors on obesity, or whether they work together.  The evidence that males are more prone to antibiotic effects on obesity also requires further investigation.  It is vital that we understand how antibiotics affect our health overall, especially because many antibiotics are used unnecessarily.”

‘Altering the intestinal microbiota during a critical developmental window has lasting metabolic consequences’ by Laura M. Cox et al. published in Cell on Thursday 14 August 2014.

Declared interests

None declared