The Industrial Revolution 150 years ago transformed human life in many ways, including granting us unlimited access to sugar. But combined with other technological advances, much of the Western population now leads a more sedentary lifestyle.
The result is a society grappling with obesity and related conditions, such as type 2 diabetes. While metformin is one of the most widely prescribed antidiabetic drugs worldwide, its precise interaction with sugar has not been fully understood — until now.
Researchers from Kobe University in Japan have found that metformin influences sugar flux in the gut and uncovered how gut bacteria use sugar to produce compounds vital for human health. Their study, published in Communications Medicine, marks an exciting discovery of a previously unknown physiological process that may aid in the development of new diabetes therapies.
“Intestinal glucose excretion represents a previously unrecognized physiological process. Understanding its molecular mechanisms and how drugs influence this system could lead to the development of novel therapeutics targeting gut microbiota and their metabolites,” said Wataru Ogawa, an endocrinologist from Kobe University, in a press release.
When Sugar Gets Out of Balance
Sugar has developed a somewhat negative reputation, but it is the body's primary energy source, fueling cellular functions and playing a crucial role in brain activity, primarily in the form of glucose.
When glucose levels are high, the liver and muscles store the excess for later use. The hormone insulin regulates this process by promoting glucose uptake into cells. However, when the body becomes resistant to insulin, diabetes develops.
Type 2 diabetes is the most common form and is often associated with excess weight, age (typically over 35), a family history of the disease, or a sedentary lifestyle. Medications such as metformin help manage blood sugar levels and reduce complications.
Read More: Sugar’s Bad Rep Is Worse Than The Sweet Stuff Itself
A Physiological Phenomenon
Previous research showed that metformin increases the excretion of glucose into the intestines, prompting researchers to investigate the dynamics of this process in greater detail. In their study, they used a newly developed bioimaging technique called fluorodeoxyglucose positron emission tomography–magnetic resonance imaging (FDG PET-MRI) to track metformin induced glucose movement in both humans and mice.
For the first time, the team observed glucose excretion in the small intestine, followed by its transport to the large intestine and rectum.
“It was surprising to find that even individuals not taking metformin exhibited a certain level of glucose excretion into the intestine. This finding suggests that intestinal glucose excretion is a universal physiological phenomenon in animals, with metformin acting to enhance this process,” said Ogawa in the release.
Their findings reveal that metformin significantly increases glucose transfer from the bloodstream to the intestines. But why is sugar being redirected back into the gut?
Read More: Your Post-Meal Sugar Cravings May Have an Evolutionary Purpose
Microbiome's Role in Sugar Metabolism
Expanding their research, the team explored glucose’s role in the large intestine and found that gut bacteria metabolize it to produce short-chain fatty acids (SCFAs).
Gut microbes generate many substances essential for human health, including SCFAs, which serve as a primary energy source for the cells lining the gut. While bacteria that feed on undigested fiber typically produce SCFAs, the study found that glucose excreted into the intestine can also fuel this process, even in the absence of fiber.
This suggests that intestinal glucose flux provides an alternative carbohydrate source for gut bacteria, enhancing SCFA production, particularly with metformin treatment. This process may contribute to the symbiotic relationship between gut microbiota and their human host.
Ogawa and his team aim to further investigate how metformin and other diabetes medications affect glucose excretion, gut microbiota, and their metabolic products. Additionally, they seek to address some limitations of their study and deepen our understanding of this newly recognized physiological phenomenon.
This article is not offering medical advice and should be used for informational purposes only.
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Communications Medicine. Metformin-regulated glucose flux from the circulation to the intestinal lumen
National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & Causes of Diabetes
Having worked as a biomedical research assistant in labs across three countries, Jenny excels at translating complex scientific concepts – ranging from medical breakthroughs and pharmacological discoveries to the latest in nutrition – into engaging, accessible content. Her interests extend to topics such as human evolution, psychology, and quirky animal stories. When she’s not immersed in a popular science book, you’ll find her catching waves or cruising around Vancouver Island on her longboard.
