The microbiome, consisting of bacteria, fungi, viruses, and other microorganisms living in and on our bodies, plays a crucial role in health. While excessive bacterial or viral growth can cause infections, the interaction among these microorganisms often benefits gut health and the immune system.

A recent study in mice published in Science in March 2025 found that alterations in the microbiome can affect insulin-producing cells leading to long-term changes and an increased risk of type 1 diabetes.

June Round, Ph.D. a professor of pathology at University of Utah Health and her team discovered that mice exposed to broad-spectrum antibiotics early in life experienced long-term metabolic health issues. These mice developed fewer beta cells responsible for insulin production in the pancreas leading to higher blood sugar levels and lower insulin levels in adulthood.  

While previous studies have linked early-life microbial diversity loss to diabetes the underlying mechanisms remain unclear. Research suggests that infants born vaginally are exposed to beneficial bacteria that support healthy development whereas those delivered via cesarean section may have a higher risk of disease.

Although the pancreas is not directly exposed to gut bacteria research from 2020 suggests that microorganisms in the gut can still influence pancreatic function and impact the immune system.  

June Round and her team aimed to investigate how the microbiome affects islet macrophages and insulin-producing beta cells in young mice as most studies on islet macrophages have focused on adult animals.  

Round’s lab at the University of Utah Health explores the role of the microbiota in five key areas: host immunity fungal effects on intestinal disease neurological disorders cancer and the influence of bacteriophages on the gut.  

In their latest study the researchers disrupted the microbiome in young mice using a broad-spectrum antibiotic cocktail containing gentamycin, neomycin, ampicillin, and erythromycin.

Round’s research revealed that beta-cell development increased in mice that were not treated with antibiotics. However in antibiotic-treated mice no such increase was observed, leading researchers to conclude that postnatal beta-cell expansion is dependent on microbial colonization.

The study also found that early antibiotic exposure had lasting effects on beta-cell mass persisting even into adulthood after antibiotic treatment had ended. This, to me, was shocking and a bit scary Round stated in a University of Utah news release. It showed how important the microbiota is during this very short early period of development. 

Additionally Round and her team identified several microbes that enhanced insulin-producing tissue and increased insulin levels in the blood. One of these microbes, a fungus called Candida dubliniensis is uncommon in healthy adults but may be more prevalent in infants.

Source: https://www.managedhealthcareexecutive.com/view/research-highlights-role-of-gut-microbiome-and-diabetes-risk