Two new studies back probiotics for diabetes

Joanna Scott-Lutyens BA (Hons) DipION

Diabetes is one of the fastest growing diseases in the UK, and the rest of the westernised world. It is estimated that by 2025 five million people will have diabetes in the UK which is equivalent to 3 people developing it every ten minutes1. Type 2 diabetes is also occurring at an increasingly younger age correlating to the 21st century increase in high carbohydrate and high fat diets.

checking for blood sugars

It is believed that 5 million people in the UK will have diabetes by 2025

It is therefore exciting to read newly published studies indicating that, subject to more research, there may be natural ways that we can compliment a healthy diet to decrease the likelihood of developing diabetes. Two recent studies, one performed on rats and the second on humans have done just that.

In order to give these studies some background it’s important to know that insulin resistance (where the cells in the body stop reacting to insulin) is a major characteristic of obesity (you can read more on this over in the Probiotics Learning Lab: gut bacteria linked to obesity) and type 2 diabetes. There are many potential mechanisms which have been implicated in the occurance of insulin resistance, such as 'impaired GLUT4 translocation' to the cell membrane and reduced skeletal muscle glucose uptake, increased liver glucose production and impaired b-cell function in the pancreas, which lead to reduced insulin secretion. In addition, there is emerging evidence to suggest that "changes in the gut microbiota might also play an important role in the development of human metabolic disease, through a mechanism that is linked to increased gut permeability, metabolic endotoxaemia and systemic low-grade inflammation.”

ice cream

The studies

The researchers of the first study published in the Journal of Diabetes2engineered a strain of Lactobacillus, a human probiotic, to secrete GLP-1. This was then administered orally to diabetic rats for 90 days in order to improve diabetes control in these rats which had the equivalent of type 1 diabetes (where the pancreas does not produce enough insulin). This genetically engineered bacterium secreted the compound GLP-1 which converted the upper intestinal epithelial cells into cells that acted very much like pancreatic cells which monitor blood glucose levels and balance insulin. After 90 days it was found that the diabetic rats where able to reduce their blood glucose levels in a similar way to the healthy rats (meaning that they were better able to produce insulin). Interestingly, blood glucose levels in the healthy rats remained unchanged due to the fact that those rats were already managing their glucose and didn’t need more insulin.

The second study3 which is of potential interest to more people, conducted by researchers at Loughborough University found that probiotic supplementation (Lactobacillus casei) may be useful in preventing insulin resistance caused by excessive consumption of high-fat foods. The study took 17 healthy individuals, split them into two groups with one group being given two bottles of probiotic fermented milk every day.

In the final week of the four week study both groups switched to a high-fat and high carb diet, with the probiotic group continuing it’s twice daily intake of probiotic.

“The main finding of the present study was that high-fat overfeeding decreased insulin sensitivity by approximately 27% in healthy young males and females; however, supplementation with the LcS probiotic before and throughout the overfeeding period preserved glycaemic control and maintained insulin action (i.e. a westernised diet)” the researchers wrote.

This is an exciting result, however more research is needed as the main limitation of this study was that the researchers couldn't be sure as to the exact mechanism as to how this was taking place.

Overall it is clear that some form of bacterial intervention is beneficial in balancing levels of insulin in both animals and humans. This, however, requires more research to investigate the exact way in which this happens. With diabetes being one of today’s most prevalent western diseases we can expect to see more research published on this in the near future. Obviously these results cannot be seen as a substitute to an education as to how changing our eating habits is paramount to the reduction in occurrence of diabetes.

If you would like to read more on this area, you may like to read Kathy's blog on how our gut bacteria play a part in metabolic conditions and obesity, over in the Probiotics Learning Lab.


  2. Duan FF, Liu JH, March JC.(2015) Engineered Commensal Bacteria Reprogram Intestinal Cells Into Glucose-Responsive Insulin-Secreting Cells for the Treatment of Diabetes. Diabetes. Published online January 27 2015
  3. Hulston C J, Churnside A A, Venables MC (2015)Probiotic supplementation prevents high-fat, overfeeding-induced insulin resistance in human subjects British Journal of Nutrition, Published online: 29 January 2015