Some guts are better than others at harvesting energy

New research from the University of Copenhagen suggests that a portion of the Danish population has a composition of gut microbes that, on average, extracts more energy from food than the microbes in the guts of fellow Danes. The research is a step toward understanding why some people gain more weight than others, even when they eat the same thing.

As unfair as that, some of us seem to gain weight just by looking at a plate of Christmas cookies, while others can snack with abandon and not gain an ounce. Part of the explanation could have to do with the makeup of our gut microbes. This, according to new research conducted at the Department of Nutrition, Exercise and Sports at the University of Copenhagen.

The researchers studied the residual energy in the faeces of 85 Danes to estimate the efficiency of their gut microbes in extracting energy from food. At the same time, they mapped the composition of gut microbes for each participant.

The results show that about 40% of the participants belong to a group that, on average, extracts more energy from food than the remaining 60%. The researchers also observed that those who extracted the most energy from food also weighed 10% more on average, or nine additional kilograms.

“We may have found a key to understanding why some people gain more weight than others, even when they don’t eat more or eat differently. But this needs to be investigated further,” says Associate Professor Henrik Roager from the department of the University of Copenhagen. nutrition, exercise and sports.

May increase the risk of obesity

The results indicate that being overweight isn’t just related to how healthy you eat or how much you exercise. It may also have something to do with the makeup of a person’s gut microbes.

The participants were divided into three groups, based on the makeup of their gut microbes. The so-called type B composition (dominated by Bacteroides bacteria) is more efficient at extracting nutrients from food and was observed in 40% of participants.

Following the study, the researchers suspect that part of the population could be disadvantaged by the presence of intestinal bacteria that are a little too efficient at extracting energy. This efficiency can translate into more calories available to the human host from the same amount of food.

“The fact that our gut bacteria are excellent at extracting energy from food is fundamentally a good thing, because the bacteria’s metabolism of food provides additional energy in the form of, for example, short-chain fatty acids , which are molecules that our body can use as a source of energy. But if we consume more than we burn, the extra energy provided by gut bacteria can increase the risk of obesity over time,” says Henrik Roager. .

Short travel time in intestinal surprises

From the mouth to the esophagus, passing through the stomach, the duodenum and the small intestine, the large intestine and finally the rectum, the food we eat travels a journey of 12 to 36 hours, passing through several stations in along the way, before the body has extracted all the nutrients from food. .

The researchers also studied the length of this trip for each participant, who all had similar eating habits. Here, the researchers hypothesized that those with long digestive journey times would harvest the most nutrients from their food. But the study found the exact opposite.

“We thought there would be a long digestive journey time that would extract more energy. But here we see that participants with the type B gut bacteria that extract the most energy, also have the fastest passage through the gastrointestinal system, which gave us food for thought,” says Henrik Roager.

Confirms previous study in mice

The new study in humans confirms previous studies in mice. In these studies, it was found that germ-free mice that received gut microbes from obese donors gained more weight than mice that received gut microbes from lean donors, despite the same diet.

Even then, the researchers proposed that the differences in weight gain could be because the gut bacteria of obese people were more efficient at extracting energy from food. This is the theory that is now confirmed in the new study from the Department of Nutrition, Exercise and Sports.

“It is very interesting to note that the group of people who have less energy in their stool also weigh more on average. However, this study does not provide evidence that the two factors are directly related. We hope to explore this further at the future.”, says Henrik Roager.

About gut bacteria:

• Everyone has a unique makeup of gut bacteria, shaped by genetics, environment, lifestyle, and diet.
• The collection of gut bacteria, called gut microbiota, is like an entire galaxy in our gut, with 100 billion bacteria per gram of stool.
• Gut bacteria in the colon serve to break down parts of food that our body’s digestive enzymes cannot, for example, dietary fiber.
• Humans can be divided into three groups based on the presence and abundance of three main groups of bacteria that most of us have: type B (Bacteroides), R-type (Ruminococcaceae) and P-type (Prevotelle).

About the study

• The energy content of stool samples from 85 overweight Danish women and men was examined.
• Participants included men and women between the ages of 22 and 66.
• 40% of the participants belonged to a special group, characterized by a lower diversity of intestinal bacteria and a faster travel time of food in their digestive tract.
• This group was also found to have less residual energy in their stools compared to the other two groups, which could not be explained by differences in habitual diet.
• The researchers also observed that the group with less energy in their stool also weighed more than the other groups.

Contact:

Henrik Roager

Associate Professor

Department of Nutrition, Exercise and Sports

University of Copenhagen

hero@nexs.ku.dk

+45 35 32 49 28

+45 25 48 06 99

Michael Skov Jensen

Journalist and team coordinator

The Faculty of Sciences

University of Copenhagen

+ 45 93 56 58 97

msj@science.ku.dk