Tip/Thought of the Day

Some Guts Better at Extracting Energy from Foods

There are many different microorganisms in and on the human body, mainly in the form of friendly bacteria. The bacteria in your gut, often referred to as the gut microbiome can impact a variety of health factors including inflammation, pain, weight levels, and even impacts chemicals in the brain. A new study suggests that some people’s gut bacteria extract more calories (energy), from food, potentially contributing to weight gain.

Beneficial bacteria in the gut helps break down and digest food, which creates important nutrients and vitamins for the body to use. The probiotic bacteria feed on fibers and turn them into helpful compounds. An unhealthy digestive system may lead to dysbiosis, which refers to an imbalance in the gut microbes. When too many harmful microorganisms grow, there may not be enough of the helpful bacteria available to keep these harmful organisms in check. It also typically means the diversity of bacteria in the gut is lower.

The study, of 85 overweight adults, categorized the participants into groups based on the dominant bacteria in their gut.

  • B-types, dominated by Bacteroides
  • R-types, where Ruminococcaceae dominate
  • P-types, dominated by Prevotella bacteria

The study found that those with the “B-type” dominant gut had less energy density in their stool samples, versus people with other bacterial profiles. Those participants on average weighed about 20 pounds more than R-type participants, explained senior researcher Henrik Roager.

The big caveat is it’s not clear what caused that weight difference, said Roager, an associate professor at the University of Copenhagen, in Denmark. Other research suggests that gut dysbiosis contributes to the development of obesity, since people at a healthy weight and people with obesity show marked differences in their gut flora. Changing the gut flora in animals caused them to lose or gain weight. Even though changing the gut flora has not shown this direct effect in humans so far, evidence does suggest that there is a shift in a person’s gut flora when they gain weight which has led researchers to believe this change is associated with obesity.

“Future studies should investigate whether individuals receiving the same amount of calories would differ in weight gain, depending on their gut microbes’ ability to extract energy,” he suggested. One study, for example, found that P-types lost weight in response to a high-fiber diet while B-types did not lose weight.

The results, he said, do not prove that B-type microbiomes actually extract more energy from food. And even if they do, it’s not clear what that means for weight gain, or weight loss. While R-types in this study weighed less than B-types, there could be any number of reasons, according to Gibbons. R-types, for example, tend to show less systemic inflammation, which can affect weight.

Every person has a unique gut microbiome composition, factors that impact your microbiome include:

  • Medications- Antibiotics can damage gut microbiota and immunity, with some research reporting that even 6 months after their use, the gut still lacks several species of beneficial bacteria.
  • Stress levels- If you’ve ever felt a stomachache when angry or nausea when nervous, you know that your gut is impacted when stress levels fluctuate. Some research shows that stress impacts what nutrients your gut can absorb, potentially leading to digestive distress or other temporary symptoms.
  • Diet- Eating a diet full of whole foods, grains, lean proteins, and healthy fats supports a balanced gut micriobiome. The Mediterranean diet is a great guideline to help support your overall health, including your gut.
  • Sugar intake- Consuming too much sugar can wreak havoc on your entire body, increasing inflammation, pain, weight gain, disrupted sleep, headaches, and an unhealthy gut. Sugar can hinder the growth and sustainability of healthy bacteria in your gut, throwing your entire system out of balance.
  • Sleep quality- Scientists have found that the gut may affect sleep and sleep-related physiological functions in a number of ways, including changing circadian rhythms, altering the body’s sleep cycle, and affecting hormones that regulate sleep.

Researchers are working to better understand how the gut microbiome impacts our wellness, but the findings so far show the broad reach it can have on our health. While everybody’s gut microbiome may react differently to foods, the bottom line is that we all benefit from a healthy, nutritious diet.










Henrik Munch Roager, PhD, associate professor, department of nutrition, exercise and sports, University of Copenhagen, Denmark; Sean M. Gibbons, PhD, associate professor, Institute for Systems Biology, Seattle, affiliate faculty, genome sciences and bioengineering departments, University of Washington, Seattle; Microbiome, Dec. 12, 2022, online




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