University of Roehampton

Type 2 diabetes mellitus (T2DM) is a major non-communicable disease and one of the world's fastest growing health problems. According to a 2019 report, about 463 million adults worldwide currently have diabetes and future projections indicate the number of diabetic patients will reach 700 million by 2045.1 T2DM is associated with significant morbidity, including increased risk of cardiovascular diseases (CVD) and stroke, hypertension, retinopathy and blindness, renal failure, and leg amputation. These place an enormous burden on individuals, society and the healthcare system.2

T2DM is a non-reversible but preventable condition with overweight and obesity being major risk factors. The onset of T2DM is gradual, with most individuals progressing from normoglycaemia through a pre-diabetic state. People with pre-diabetes, defined as having impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or impaired glycated haemoglobin (HbA1c),2 are at increased risk of developing T2DM and its associated complications, such as CVD and retinopathy, which can develop even in the absence of progression to overt T2DM.3-5 Pre-diabetes is a prevalent and potentially reversible condition that provides an important window of opportunity for healthcare providers to implement interventions that can delay or prevent T2DM and its complications.

A substantial body of literature has provided evidence for the role of gut microbiota in metabolic diseases including type 2 diabetes.6 Indeed, there is evidence for the effects of microbiota on glucose metabolism in both preclinical animal models of T2D and in healthy animals, by means of increasing the number of inflammatory mediators, chronic inflammation, insulin resistance and increased energy intake. Among the commonly reported findings, Bifidobacterium spp appears to be the most consistently supported by the literature genus containing microbes potentially protective against T2DM. Indeed, nearly all papers report a negative association between this genus and T2DM;7-14 while only one paper reported opposite results.15

In view of the correlation between gut microbiota, more specifically Bifidobacterium spp., and diabetes, the Bifidobacterium population and their metabolic action can be taken as an important target for interventions to prevent and/or delay the development of T2DM.