Led by researchers at King's College London, the team used data from the TwinsUK study to analyse the impact of genetics and microbiome in driving the way fat is processed and distributed in the body.
By analysing faecal metabolites – chemicals produced by our gut microbes that are found in stool samples – the UK-led team identified biomarkers for the build-up of internal fat around the waist. Such visceral fat is strongly linked with the development of conditions including type 2 diabetes, heart disease and obesity.
Led by senior author Dr Cristina Menni, the team found that less than a fifth (17.9%) of processes could be linked to host genetics and hereditary factors. However 67.7% of activity was found to be influenced by environmental factors, mainly a person's regular diet.
“This study has really accelerated our understanding of the interplay between what we eat, the way it is processed in the gut and the development of fat in the body, but also immunity and inflammation,” said Menni. “By analysing the faecal 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.”
Dr Jonas Zierer, first author of the study, added that the new knowledge from the findings “means we 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.”
“This is exciting, 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 fibre diets,” he said.
Writing in Nature Genetics the team describe the study which analysed 1,116 metabolites from 786 individuals from the population-based TwinsUK study.
By understanding how these microbial metabolites lead to the development of fat around the waist in some, but not all the twins, the King's team hoped to also advance the understanding of the very similar mechanisms that drive the development of obesity.
With data from 500 pairs of twins, Menni and her colleagues aimed to build up a picture of how the gut governs the processes and distributes fat and assess how much of that activity is genetic and how much is determined by environmental factors.
“This exciting work in our twins shows the importance to our health and weight of the thousands of chemicals that gut microbes produce in response to food,” commented Professor Tim Spector, head of the King's College London's Twin Research Group.
On the back of the study, the Kings team 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 metabolites in the gut – something that could help other scientists to understand how bacteria in the gut affect human health.
“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,” added Spector. “In the future these chemicals could even be used in smart toilets or as smart toilet paper.”
Source: Nature Genetics
Published online ahead of print, doi: 10.1038/s41588-018-0135-7
“The fecal metabolome as a functional readout of the gut microbiome”
Authors: Jonas Zierer, et al