August 22, 2012

expert reaction to new studies into antibiotics and obesity

A large study in the International Journal of Obesity found children under six months who were given antibiotics were heavier when older, while a Nature paper found consistent treatment of young mice with antibiotics affected their gut microbes and caused gains in fat.

Prof Brendan Wren, Professor of Microbial Pathogenesis, London School of Hygiene & Tropical Medicine, said:

“The role of the composition of our gut microflora is increasingly recognised as being important and has been linked to inflammatory bowel disease, metabolic disorders, immunity and obesity. It has been considered as the forgotten super organ in humans, and it is only now through advances in genome sequencing that we can assess the composition of the complex population of microbes in the gut. Thus there has been a surge of publications measuring the changes in the relative gut microflora composition that is affected by diet, probiotics (e.g. yogurts), age (e.g. birth, infancy and elderly) and of course the consumption of broad range antibiotics, that are indiscriminate and rapidly affect the balance of our bowel microflora with unforeseen consequences. Indiscriminate use of antibiotics for livestock (often used to fatten animals), not only promotes the spread of antibiotic resistance, but can get in our food chain and affect the homeostasis of our gut microflora.”

Dr Cormac Gahan, Dept of Microbiology, University College Cork, said:

“These studies support an emerging body of evidence linking gut bacteria with the development of obesity. Other research has identified specific subgroups of gut bacteria that play a role in energy extraction from the diet and influence the production of hormones in the host. Disrupting this finely balanced ecosystem clearly has consequences for host metabolism and weight gain.”

‘Infant antibiotic exposures and early-life body mass’ by Trasande et al. was published in the International Journal of Obesity. ‘Antibiotics in early life alter the murine colonic microbiome and adiposity’ by Cho et al., published in Nature on Wednesday 22 August.