Having more diverse gut bacteria (greater microbiome richness) and specifically a greater abundance of 12 types of butyrate-producing bacteria were both associated with less insulin resistance and less type 2 diabetes, in a population-based observational study from the Netherlands.
Several studies have reported that there is less microbiome diversity in type 2 diabetes, Zhangling Chen, MD, PhD, of Erasmus Medical Center, Rotterdam, the Netherlands, and colleagues note.
Their study also identified a dozen types of bacteria that ferment dietary fiber (undigested carbohydrates) in the gut to produce butyrate, a short-chain fatty acid, which may play a role in protection against type 2 diabetes.
“The current study is the first, to our knowledge, to comprehensively investigate the associations between gut microbiome composition [and] type 2 diabetes in a large population-based sample … which we adjusted for a series of key confounders,” the researchers write.
“These findings suggest that higher gut microbial diversity, along with specifically more butyrate-producing bacteria, may play a role in the development of type 2 diabetes, which may help guide future prevention and treatment strategies,” they conclude in their study published online July 29 in JAMA Network Open.
Confirmation of previous work, plus some new findings
The study confirms what many smaller ones have repeatedly shown – that low gut microbiome diversity is associated with increased risks of obesity and type 2 diabetes, Nanette I. Steinle, MD, RDN, who was not involved in the research, said in an interview.
A diet rich in fiber and prebiotics promotes gut biome diversity, added Dr. Steinle, chief of the endocrinology and diabetes section at Maryland Veterans Affairs Medical Center in Baltimore.
The findings add to other research, she noted, such as a prospective trial in which a high-fiber diet induced changes in the gut microbe that were linked to better glycemic regulation (Science. 2018;359:1151-6) and a study of a promising probiotic formula to treat diabetes.
“An important next step,” according to Dr. Steinle, “is to provide interventions like healthy diet or specific fiber types to see what can be done to produce lasting shifts in the gut microbiome and if these shifts result in improved metabolic health.”
Natalia Shulzhenko, MD, PhD, said: “Some of associations of taxa [bacteria groupings] with type 2 diabetes reported by this study are new.”
Dr. Shulzhenko and colleagues recently published a review of the role of gut microbiota in type 2 diabetes pathophysiology that summarized evidence from 42 human studies as well as preclinical studies and clinical trials of probiotic treatments (EBioMedicine. 2020;51:102590).
“Besides adding new microbes to the list of potential pathobionts [organisms that can cause harm] and beneficial microbes for type 2 diabetes,” the findings by Dr. Chen and colleagues “support a notion that different members of the gut microbial community may have similar effects on type 2 diabetes in different individuals,” commonly known as “functional redundancy,” Dr. Shulzhenko, associate professor, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, pointed out in an email.
Also “in line with previous studies,” the study shows that butyrate-producing bacteria are associated with type 2 diabetes.
She speculated that “these results will probably contribute to the body of knowledge that is needed to develop microbiota-based therapy and diagnostics.”