Why thin people might thank their gut for their girth

You flush them away without thinking about it, but the bacteria that live in our gut could be key to deciding whether or not we are fat or thin.

New research published today in the journal Cell identifies a new group of gut bacteria that are more common in the guts of thinner people.

Using a unique register of British twins the researchers then demonstrated that our genes play an important role in determining whether we host communities of bacteria that are beneficial to our weight.

“Our findings show that specific groups or microbes living in our gut could be protective against obesity – and that their abundance is influenced by our genes,” said Professor Tim Spector, head of the Department of Twin Research at King’s College London.

The researchers identified a new family of ancient methane producing bacteria called Chistensenellaceae that are found in nearly everybody’s guts, but are more prevalent in the bellies of slimmer people.

They demonstrated the role of the bacteria by transplanting them into the guts of fat mice – and showed they got slimmer as a result.

Chistensenellaceae

Efforts to use such ‘probiotic’ treatments in humans haven’t been very successful. But the researchers propose that Chistensenellaceae could form a basis for new probiotics that aid weight loss.

“The human microbiome represents and exciting target for dietary changes and treatments aimed at combatting obesity,” said Professor Spector.

Using more than 400 pairs of twins some identical, others non-identical, the researchers were able to show that our genetic background is crucial in dictating how likely we are to host different ratios of beneficial bacteria.

In future, the researchers argue, an understanding of our gut microbes combined with our genetic background could help devised personalised probiotic therapies that could help people predisposed to obesity manage their weight.

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