Scientists have found a new link between the diversity of bacteria in human poo – the human faecal microbiome – and levels of harmful types of body fat.

In research that may help explain why excessive weight problems and obesity tend to run in families, the scientists said high levels of visceral fat (body fat stored in organs in the abdominal area such as the liver, pancreas intestines)  – which is linked to risks of chronic disease – were connected to having a relatively small range of bacteria in faeces.

In other words, those with more diversity of bacteria in their faeces had lower levels of visceral fat, according to the study published in the journal Genome Biology.

Visceral fat is harmful because it sits around important organs like the liver, pancreas and intestines. It is linked to higher risks of diabetes and heart disease.

When you have more diverse gut bacteria in you, you have a lower risk of obesity, says study.

When you have more diverse gut bacteria in you, you have a lower risk of obesity, says study.

The scientists used data from stool samples from 1,313 twins already involved in a large research project called TwinsUK.

Extracting DNA information about faecal microbes from the samples, they compared it to six measures of obesity, including body mass index, visceral and other fat levels, and upper to lower body fat ratios. They found the strongest links with visceral fat.

Michelle Beaumont, who led the work at King’s College London, said it showed “a clear link between bacterial diversity in faeces and markers of obesity and cardiovascular risk.”

But she cautioned that since this was an observational study, it could not give any causal mechanisms for how gut and faecal bacteria might affect fat.

Jordana Bell, also from King’s twin research department, said more studies were needed to understand precisely how gut microbes influence human health and to explore possible new ways of preventing obesity.

Further research would also help in investigating a possible role for procedures like faecal transplants – a treatment currently used in patients with an infection called C.difficile colitis which replaces their unhealthy faecal microbiome with a healthy one from a donor. – Reuters/Kate Kelland

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