New data suggests that a certain composition of gut bacteria influences obesity by how it extracts energy from the diet.
One more year we can see that there are two types of people: those who can indulge in nougat without regretting a large weight gain, while others gain weight just by sitting near the tray of polvorones. For a long time, scientific research has collected other types of factors in addition to environmental ones, such as the type of diet and sedentary lifestyle that also influence obesity.
Among these elements, it has been hypothesized that the intestinal microbiota influences obesity through its ability to extract energy from the diet.
This is the line of research followed by a group of scientists from the University of Copenhagen, whose conclusions have been published in Microbiome.
The study suggests that the population of intestinal bacteria that is most efficient at extracting energy from food is found in people who weigh on average 10% more (about 9 kilograms) than those whose microbiota was not as efficient.
“We may have found a key to understanding why some people gain more weight than others, even when they don’t eat more or differently. But this needs to be investigated further,” says Professor Henrik Roager, from the Department of Nutrition, Exercise and Sport at the University of Copenhagen, in a note on the study.
To reach this conclusion, the researchers have analyzed the residual energy in the feces of 85 people, in which they also determined their microbial composition.
40% of these individuals were classified in a group that extracted more energy from the food consumed than the remaining 60%.
The participants were divided into three groups, based on the composition of their gut microbes. As detailed in the study, the so-called type B composition (dominated by bacteria Bacteroides) was shown to be more effective in extracting nutrients from food, since individuals with this enterotype had a significantly lower energy density in feces compared to other types of composition.
Specifically, those people where the family predominated Ruminococcaceae (type R). A third group, that of individuals with Prevotella (type P) fell between type B and type R. “Notably, the body weight of type R individuals was significantly lower than that of type B,” these scientists write.
A striking finding that these researchers also highlight was that people with a type B microbiota also had the shortest intestinal transit times. They hypothesized that a longer digestive journey would be found in people who extract more nutrients from food, but the study showed the exact opposite.
“A prolonged intestinal transit time does not necessarily lead to a more complete depletion of the food substrate, but is accompanied by a shift in microbial fermentation from saccharolytic to proteolytic metabolism, which negatively affects energy extraction from the intestinal microbiota and leads to a less complete depletion of the food substrate, as reflected by the higher energy density of feces”, they argue about this association.
More evidence of influence on obesity
These findings that relate the microbiota to obesity are consistent with experiments carried out with murine models, where it was seen that the mice without the microbial population that received intestinal bacteria from obese donors increased their weight more compared to the mice that received the microbiota from lean donors, despite to maintain the same diet.
“Our study shows that the energy density of feces, as an indicator of the energy use of the intestinal microbiota, is associated with intestinal transit time and the structures of the microbial community. The study provides the first evidence to suggest that differences in the structures of the human intestinal microbial community, reflected by enterotypes, affect the ability of the intestinal microbiota to extract energy from food”, conclude these researchers, for whom the association observed could be useful to establish personalized weight control treatments. Sonia Moreno