Nutrition and the body's synthesis of the intestinal defense molecule defensins, which has been found by researchers at Ume University in Sweden, are two variables that have an impact on the makeup of the gut microbiota. Instead, scientists found that these molecules may have a role in preventing the blood sugar levels from increasing after ingesting a high-calorie “Western-style diet.”
The Department of Molecular Biology at Umea University PhD student Fabiola Puertolas Balint said, “Our research highlights their protective role against the metabolic complications that can arise after the intake of a high-fat and high-sugar Western-style diet. While the effect of defensins in shaping the adult microbiota composition is rather minor when compared to diet, defensins still have a very important role in protecting us against microbial infections. She is a member of the research team led by Bjorn Schroder at Umea University, which is also connected to the Umea Centre of Microbial Research (UCMR) and The Laboratory for Molecular Infection Medicine Sweden (MIMS).
The population of billions of bacteria that inhabit every person's gut is referred to as the gut microbiota. Due to its link to several illnesses, such as inflammatory bowel diseases, obesity and diabetes, and even psychiatric issues, the prevalence of certain bacteria in this population has been thoroughly examined over the last few decades. A number of internal and external variables assist shape the microbial community to its ultimate composition once the community is seeded during birth. Diet (particularly fiber), genetics, medications, exercise, and defense molecules, or so-called antimicrobial peptides, are a few of these determinants.
It is possible to think of antimicrobial peptides as the body's own naturally occurring antibiotic compounds. All bodily surfaces, including the skin, the lungs, and the digestive system, generate the defensins, the biggest category of antimicrobial peptides. Defensins are regarded to be the immune system's first line of defense against infections, but they are also crucial for determining the makeup of the microbiota in the small intestine. The magnitude of their effects relative to diet, which is known to have a significant impact, was not yet established.
The Bjorn Schroder lab used normal, healthy mice to compare the microbiota composition in the small intestine to mice who were unable to produce functional defensins in the gut. Both mouse groups were then fed either a healthy diet or a low-fibre Western-style diet to further investigate this.
“We were surprised – and slightly disappointed – that defensins had only a very minor effect on shaping the overall microbiota composition when we analysed the microbiota composition inside the gut and at the gut wall of two different regions in the small intestine,” said Bjorn Schroder.
The gut wall, where the defensins are generated and secreted, was where the intestinal defensins still had some impact. Due to the defensins' selective antimicrobial action, a few specific bacteria, including Dubosiella and Bifidobacteria, seemed to be harmed under this situation.
Bjorn Schroder remarked, “To our surprise, we also discovered that a Western-style diet combined with a lack of functional defensins resulted in elevated fasting blood glucose readings, indicating that defensins may assist to guard against metabolic problems while consuming an unhealthy diet.