Study reveals gut bacteria's hidden fuel boosts blood sugar and liver health

A New Approach to Treating Metabolic Diseases

A groundbreaking discovery by a team of Canadian scientists has revealed an innovative method for improving blood sugar levels and reducing liver damage. The research focuses on a previously overlooked substance produced by gut bacteria, which can cause harm if not controlled. By trapping this molecule before it enters the bloodstream, scientists have found a promising way to combat metabolic diseases such as type 2 diabetes and fatty liver disease.

The findings, published in Cell Metabolism, could lead to new therapeutic approaches for these conditions. Researchers from McMaster University, Université Laval, and the University of Ottawa demonstrated that a specific molecule generated by gut microbes can enter the bloodstream and stimulate the liver to produce excessive glucose and fat. However, when they developed a technique to trap this molecule in the gut, they observed significant improvements in blood sugar regulation and liver health in obese mice.

Jonathan Schertzer, a senior author and professor at McMaster University, described the discovery as a new twist on a well-known metabolic process. "We've known for nearly a century that muscles and the liver exchange lactate and glucose—a process called the Cori cycle. What we've discovered is a new branch of that cycle, where gut bacteria are also part of the conversation."

This concept traces back to 1947 when Carl Ferdinand Cori and Gerty Theresa Cori were awarded the Nobel Prize for their work on how muscles generate lactate that fuels the liver to produce blood glucose, which then cycles back to fuel the muscle. Their research laid the foundation for understanding how muscles and the liver communicate through lactate and glucose.

The Canadian team found that both obese mice and individuals with obesity have higher levels of D-lactate in their blood. Unlike the more familiar L-lactate produced by muscles, most of the D-lactate comes from gut microbes and has been shown to increase blood sugar and liver fat more aggressively.

To address this issue, researchers created a "gut substrate trap"—a safe and biodegradable polymer that binds to D-lactate in the gut, preventing its absorption into the bloodstream. Mice that consumed this trap exhibited lower blood glucose levels, reduced insulin resistance, and less liver inflammation and fibrosis—without any changes in diet or body weight.

"This is a completely new way to think about treating metabolic diseases like type 2 diabetes and fatty liver disease," said Schertzer. "Instead of targeting hormones or the liver directly, we're intercepting a microbial fuel source before it can do harm."

The research underscores the growing significance of the microbiome in chronic diseases. As scientists continue to explore the complex interactions between gut bacteria and human health, discoveries like this offer hope for new treatments that target the root causes of metabolic disorders.

Further details about the study can be found in the article titled "Gut substrate trap of D-lactate from microbiota improves blood glucose and fatty liver disease in obese mice," published in Cell Metabolism. The study provides valuable insights into how gut bacteria contribute to metabolic health and opens the door for future research and potential therapies.