On the 4th May 2016 The Telegraph released an article with the headline ‘Obesity could be contagious like the superbug C.diff, suggests scientists’. This heading rested on top of a picture of a morbidly obese individual’s bottom as they sat on a chair that was clearly too small for them. Under the picture it read ‘The gut bacteria which are thought to trigger weight gain could be picked up from spores in the air’. Scary stuff! And this has been suggested by UK scientists, so it must be right, right?
The article continues confirming this hypothesis on the subject of contagious obesity as it correlates with another study by Washington University carried out a decade ago and that found ‘adding gut microbes from obese mice to thin mice caused huge gains in weight’.
As a member of the public, would I put my faith in this article? Maybe, two studies by scientists have both found this to be true. Right?
As a scientist I want to read the scientific papers to confirm this media claim. This media story originated from an article published by the Wellcome Trust Sanger Institute titled, ‘Culturing of ‘Unculturable’ human microbiota reveals novel taxa and extensive sporulation’. The researchers has produced an interesting report exploring characteristics of bacteria living in the human gut and whether these types of bacteria could survive in an oxidative environment. However, the study did not look at any links to obesity, alluding to it, or making any suggestions about contagion.
Where did The Telegraph story come from? The Sanger Institute study focused on bacteria in the human gut and found that 40% of the gut bacteria known to scientists could be cultured. Researchers continued to investigate these bacteria and found some can live and be transferred out the body by producing pores which can be transported by gut acids. This transportability appears to be the origin of The Telegraph journalist’s ideas about obesity being contagious through spores. However, the Sanger study never mentions obesity, so where does the idea of obesity come into play? Click to read the paper
What about the other paper The Telegraph mentions? In 2006 the University of Washington published a paper titled ‘Metabolic profiling reveals a contribution of gut microbiota to fatty liver phenotype in insulin-resistant mice’. The paper looked at gut-microbial and their relationship to metabolism in mice. Their observations indicated that gut-microbial effected the metabolism of the host (mice), which supported their hypothesis that gut bacteria could play a role in insulin sensitivity… in mice.
The telegraph took the hypothesis from the Washington story that gut bacteria could affect the metabolism of mice. The findings from the Sanger Institute that 40% of gut bacteria (It is prudent to mention the bacterial effect on the body are unknown) can be transported by spores and came up with the head-line ‘Obesity could be contagious like the superbug C.diff”, suggests scientists. My question to you is, did either of these studies suggest you could ‘catch’ obesity?
The answer is no, there is no evidence especially from this paper to suggest otherwise. In fact the Sanger Institute issued a press release in reaction to this story confirming in no way did they suggest obesity is contagious.