Microbes may be to blame for gaining weight at Christmas, study suggests
A new study could explain why you gain weight after Christmas while your family members stay lean, even when they eat the same amount as you.
Researchers have studied how much energy Danes take in from their food, based on analysis of their feces and the microbes they contain.
They found that about 40 percent of the participants have microbes that, on average, extract more energy from food compared to the other 60 percent.
The researchers suspect that similar portions of populations may be disadvantaged by having gut bacteria that are too effective at extracting energy.
A new study could explain why you gain weight after Christmas while your family members stay slim. Part of the explanation could be related to the composition of our gut microbiota: the community of millions of microorganisms in the gut.
What is the intestine made of?
Inside your gut live 300 to 500 different types of bacteria containing almost 2 million genes.
Along with other tiny organisms such as viruses and fungi, they make up what is known as the microbiota.
Like a fingerprint, each person’s microbiota is unique: the mix of bacteria in your body is different from everyone else’s mix.
It is determined partly by your mother’s microbiota, the environment you are exposed to at birth, and partly by your diet and lifestyle.
Bacteria live throughout your body, but the ones in your gut can have the biggest impact on your well-being.
They line up your entire digestive system. Most live in the intestines and colon.
There’s evidence that it affects everything from your metabolism to your mood to your immune system.
The new study, published in the journal microbiomewas led by experts from the Department of Nutrition, Exercise and Sports at the University of Copenhagen.
The authors say it’s a step toward understanding why some people gain more weight than others, even when eating the same things.
“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,” said study author Professor Henrik Roager. .
For the study, the experts analyzed the intestinal microbiota, the community of millions of microorganisms in the intestine, from stool samples of the participants.
The researchers describe the gut microbiota as “like a whole galaxy in our gut,” with a staggering 100 billion per gram of faeces.
The research team studied residual energy in the feces of 85 overweight Danes aged 22 to 66 to estimate how effective their gut microbes were in extracting energy from food.
At the same time, they mapped the composition of each participant’s gut microbes.
The participants were divided into three groups, based on the composition of their gut microbes: ‘type B’, type R’ and ‘type P’.
Type B has been repeatedly linked to a western lifestyle low in microbiota-accessible carbohydrates (MAC) typically found in fruits and vegetables, compared to type P, for example, linked to a diet rich in MAC.
The so-called type B composition (dominated by Bacteroides bacteria), seen in 40 percent of the participants, was most effective at extracting nutrients from food, the experts found.
The researchers also found that those who extracted the most energy from food weighed 10 percent more on average, which was an extra nine kilograms.
Types of gut microbiota
dominated by the bacterium Bacteroides
dominated by the bacterium Ruminococcaceae
dominated by the bacterium Prevotella
The efficiency of extracting nutrients in type B people may result in more calories being available from the same amount of food, possibly leading to obesity.
“The metabolism of food by bacteria provides additional energy in the form of, for example, short-chain fatty acids, molecules that our bodies can use as fuel for energy supply,” said Professor Roager.
“But if we consume more than we burn, the additional energy provided by gut bacteria may increase the risk of obesity over time.”
The researchers also studied the journey time of food from the mouth, digestive system, and rectum for each participant, all of whom had similar dietary patterns.
They hypothesized that those with the longest digestive journey times would extract the most energy from their food, but the study found otherwise.
Participants with type B gut bacteria (the type associated with extracting the most energy) also had the fastest passage through the gastrointestinal system.
“Although slower intestinal transit would theoretically allow for greater energy extraction, fecal energy density was positively associated, contrary to what might be expected, with intestinal transit time,” the team says.
Illustration of the new study. The researchers had hypothesized that those with the longest digestive journey times would extract the most energy from their food, but the study found otherwise.
“This apparent contradiction requires further unraveling of the driving forces that shape the gut microbial ecosystem.”
Although the scientists only used a small sample of Danish participants, it is possible that the findings could be applied to other global populations.
Overall, the results indicate that being overweight might not only be related to how one eats healthily or how much exercise one gets, but may also have something to do with the microbes in our gut.
The new study also confirms previous studies in rodents, including one co-authored by Professor Roager that was published in 2016.
In these studies, rodents that received gut microbes from obese donors gained more weight compared to rodents that received gut microbes from lean donors, despite receiving the same diet.
Read similar stories here…
Dogs with more active owners ‘get more exercise’
Patients could ‘lose 10% of weight in months’ with injection of diet drugs
Children up to 5 years old see thin people as happier and more attractive
Gut bacteria in healthy older people become “increasingly unique” as they age, as their microbiome produces life-extending chemicals
Scientists say your gut microbiome, the trillion-strong community of microorganisms in your belly, can help predict whether you’ll live a long and healthy life.
US researchers have identified distinct signatures in the gut microbiome that are associated with healthy or unhealthy aging trajectories.
In healthy individuals, gut microbiomes become increasingly unique, diverging in different ways that are specific to the individual, compared to unhealthy individuals.
This uniqueness is strongly associated with amino acid derivatives produced by microbes circulating in the bloodstream, suggesting life-extending chemicals.
This knowledge means that microbiomes can be used to predict survival in a population of older people, according to experts.