Our bodies secretly feed intestinal bacterial sugar through hidden pathways, research shows

Surprisingly, our understanding of our relationship with trillions of microorganisms in the gut, researchers found that our bodies actively feed sugar directly into gut bacteria, a previously unknown biological exchange that challenges our routine understanding of how to live with microbial partners.

The discovery, published on March 3 by a team at Kobe University in Communication Medicine, reveals that glucose, the body’s main energy source, has been secreted from our blood directly into the intestines, where resident bacteria transform it into necessary compounds for our bodies that our bodies need but cannot produce themselves.

This discovery overturned a long-standing belief that gut bacteria exist primarily on undigested dietary fiber and opened up new possibilities for the treatment of metabolic diseases such as diabetes.

Sugar secretions: a two-way street

Using advanced imaging techniques developed specifically for this study, the team observed that glucose is actively excreted from the blood into the jejunum of the small intestine and then moved through the intestine to the large intestine.

“It is surprising that even people who do not take metformin will show a certain degree of glucose excretion in the intestine. This finding suggests that intestinal glucose excretion is a common physiological phenomenon in animals, and the effect of metformin can enhance this process,” explains Ogawa Wataru, an endocrinologist at Kobe University.

The researchers made this finding when investigating metformin in vivo, the world’s most widely prescribed diabetes drug. Previous observations suggest that metformin somehow increases glucose accumulation in the intestine, but the mechanism remains elusive.

Through careful measurements of humans and mice, the team found that metformin increased this natural glucose excretion nearly fourfold. This effect occurs regardless of whether the subject has diabetes or not, suggesting that this is an enhancement to normal biological processes, not a correction to the disease.

Bacteria turn our gift into something we need

The study further reveals what happens after this glucose enters the gut. As it passes through the intestine, bacteria metabolize sugars into short-chain fatty acids – crucial for numerous body functions, from providing energy to intestinal cells to regulating immune responses.

“The production of short-chain fatty acids that excrete glucose is a huge discovery. Although these compounds are traditionally believed to be produced by the intestinal microbiota fermentation of indigested dietary fiber, this newly identified mechanism highlights a novel symbiotic relationship between the host and its microbiota,” Ogawa notes.

The researchers used mice specially labeled glucose molecules (containing the stable isotope carbon 13) to track how sugars are converted into short-chain fatty acids in the intestine. This transformation ceases when they administer antibiotics to kill gut bacteria, confirming that microorganisms are the cause of transformation.

Quantitative exchange

This glucose secretion is very large. The researchers calculated that in people who do not take metformin, the body expels about 0.41 grams of glucose from the intestine every hour. Among people taking metformin, this increased to about 1.65 grams per hour, accounting for 20% of the total liver glucose output during fasting.

For comparison, the amount is excretion of glucose in the urine, another diabetes medication that causes the kidney to remove sugar from the blood.

To take the perspective of these findings, the researchers used advanced bioimaging techniques to accurately track glucose movement. They used a combination of positron emission tomography (PET) and magnetic resonance imaging (MRI) (MRI) to monitor radiolabeled glucose (fluorodeoxyglucose or FDG) – creating a new method called PET-MER (magnetic resonance intestinal sogracnagragy).

Impact on health and disease

This newly discovered glucose pathway may help explain some of the beneficial effects beyond metformin control. The drug is associated with improvements in gut health and changes in microbiome composition, which may be partly due to its enhancement of this natural feeding process.

These findings can also open up new avenues for the treatment of metabolic diseases by targeting mechanisms that control glucose secretion into the intestine or directly regulating how gut bacteria process this glucose.

Intestinal glucose excretion represents a previously unidentified physiological phenomenon. Learn about the development of novel therapeutic agents designed to regulate the gut microbiota and its metabolites, understand the underlying molecular mechanisms and how drugs interfere with this process. ” Ogawa said.

While the exact mechanism of how glucose is delivered from the blood to the intestine is unknown, researchers suspect it may involve glucose transporters known to be affected by metformin.

Two-way relationship

This study adds important aspects to our understanding of the relationship between human microbiomes. Instead of simply providing bacterial habitat and benefiting from metabolic yields, our bodies seem to actively provide resources to support microbial communities.

This study reveals a more complex and interdependent relationship than previously recognized – we feed microbial partners directly, which in turn produce compounds that are essential to our health.

As researchers continue to explore this avenue, they hope to reveal how other diabetes drugs affect the process and may develop new treatments to leverage new discovered aspects of our relationship with gut microbes.

For now, this discovery reminds us that we still have to know how much we have to know about the complex biological communication that happens every day, and how the boundaries between “we” and “we” we host and the microorganisms we host continue to blur as science advances.