Gut bacteria link to diabetes

“We have demonstrated that people with type-2 diabetes have a high level of pathogens in their intestines,” says professor Jun Wang from the University of Copenhagen’s Department of Biology and Novo Nordisk Foundation Center for Basic Metabolic Research (Science Daily, Sept 26th 2012).  In this study, researchers examined the intestinal flora of 345 people from China, of which 171 had type-2 diabetes. Clear biological indicators emerged, and the type-2 subjects had microbiome environments which were more hostile, increasing resistance to drugs. This imbalance in the gut reflected previous findings with Danish subjects showing that people who were ‘at risk’ of type-2 diabetes had abnormal gut bacterial levels.

That study indicated the typical characteristics of the intestinal flora of type 2 diabetes patients. “It’s a typical flora for someone with a mild form of gastroenteritis” says Jeroen Raes. “Now it is also important to include the Western population to see if these markers may be predictors — then the path is open for early diagnostic tests.”

Child Research led by Professor Jayne Danska at the Sick Children’s Hospital of the University of Toronto and Professor Andrew Macpherson in the Clinic for Visceral Surgery and Medicine at the Inselspital and the University of Bern have shown that irregularities in intestinal bacteria may well be causal.

More than 30 years ago Japanese researchers noticed that a strain of NOD laboratory mice tended to get diabetes. Now Danska and Macpherson’s teams have shown that the intestinal bacteria, especially in normal male mice, can produce biochemicals and hormones that stop diabetes developing.

In Nature, 29 May 2013 (Gut metagenome in European women with normal, impaired and diabetic glucose control), researchers at the Sahlgrenska Academy, University of Gothenburg, Sweden and Chalmers University of Technology, Sweden, have confirmed that women with type-2 diabetes have an altered gut microbiota and lowered levels of bacteria capable of producing sodium butyrate.

On the basis of these findings, the researchers have developed a new predictive model.

And it is possible that wheat may have a negatively influencing effect on diabetes too. In November 2013, (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3827256/), the following conclusions were made by Mayo Clinic researchers with non-obese diabetic (NOD) mice

  1. GCC-fed (gluten-containing chow fed) NOD mice had the expected high incidence of hyperglycemia (elevated blood sugar) whereas NOD mice fed with a GFC (gluten-free chows) had significantly reduced incidence of hyperglycemia.
  2. When comparing microbiomes, Bifidobacterium, Tannerella, and Barnesiella species were increased in the intestinal microbiome of GCC mice, where as Akkermansia species was increased in the microbiome of NOD mice fed GFC.
  3. Both of the gluten-free chows that were evaluated (egg white based, or casein based), significantly reduced the incidence of hyperglycemia.

It also seems that children who develop type-1 diabetes have different gut flora. University of Florida researchers have shown that the variety of bacteria present in a young child’s gut is linked to whether it develops type-1 diabetes. Type-1 diabetes has been a medical mystery as there seems little genetic link; less than 15 per cent have another family member with diabetes. Now researchers think the trigger is gut bacteria.

Mark Atkinson, Professor at the University looked at Finnish research which first showed a link. (Finland has a very uniform genetic pool and so is perfect for this sort of research.)  “Diabetes is caused when the body’s own immune system destroys insulin-producing cells in the pancreas. It is not clear why.” An unbalanced mix of bactreria in the gut seems to be related in some way. Various theories are suggested – for example, one theory is that the particular mix of bacteria make the gut wall weak, allowing quite large and complex proteins to cross into the blood stream. The immune system may over-react to them and cause random damage. Another route may be that certain bacteria that are missing would normally suppress inflammation and immune response. University of Florida researchers suggest that this is how poor levels and imbalalance of gut bacteria lead to immunological diseases like Crohn’s, celiac disease and even multiple sclerosis. Importantly, in their view, “the bacterial mix becomes unstable first”.