Some processes in gut drive fat build-up around waist, new study finds
Research into the role the gut plays in processing and distributing fat could pave the way for the development of personalized treatments for obesity and other chronic diseases within the next decade, according to scientists at King's College London, whose study was published May 28 in the journal Nature Genetics.
In the largest study of its kind, scientists analyzed the fecal metabolome—the community of chemicals produced by gut microbes in the feces—of 500 pairs of twins to build up a picture of how the gut governs these processes and distributes fat. The team also assessed how much of that activity is genetic and how much is determined by environmental factors.
The analysis of stool samples identified biomarkers for the build-up of internal fat around the waist. It's well known that this visceral fat is strongly associated with the development of conditions including type 2 diabetes, heart disease, and obesity.
By understanding how microbial chemicals lead to the development of fat around the waist in some, but not all the twins, the researchers hope to also advance the understanding of the very similar mechanisms that drive the development of obesity.
An analysis of fecal metabolites, chemical molecules in stool produced by microbes, found that less than a fifth (17.9 percent) of gut processes could be attributed to hereditary factors, but 67.7 percent of gut activity was found to be influenced by environmental factors, mainly a person's regular diet.
This means that important changes can be made to the way an individual's gut processes and distributes fat by altering both their diet and microbial interactions in their gut.
On the back of the study, researchers have built a gut metabolome bank that can help other scientists engineer bespoke and ideal gut environments that efficiently process and distribute fat. The study has also generated the first comprehensive database of which microbes are associated with which chemical metabolites in the gut. This can help other scientists to understand how bacteria in the gut affect human health.
Lead investigator Cristina Menni, PhD, from King's College London, said the study accelerated the understanding of the interplay between what we eat, the way it is processed in the gut, and the development of fat in the body, as well as immunity and inflammation.
“By analyzing the fecal metabolome, we have been able to get a snapshot of both the health of the body and the complex processes taking place in the gut,” she said.
In addition, the results show the importance to our health and weight of the thousands of chemicals that gut microbes produce in response to food, said Tim Spector, PhD, head of the King's College London's Twin Research Group Professor.
“Knowing that they are largely controlled by what we eat rather than our genes is great news, and opens up many ways to use food as medicine,” said Spector. “In the future these chemicals could even be used in smart toilets or as smart toilet paper.”
'This new knowledge means individuals can alter the gut environment and confront the challenge of obesity from a new angle that is related to modifiable factors such as diet and the microbes in the gut, according to Jonas Zierer, PhD, the first author of the study.
“This is exciting,” he said, “because unlike our genes and our innate risk to develop fat around the belly, the gut microbes can be modified with probiotics, with drugs or with high fiber diets.”