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Causes of Type 1: Infections and the Leaky Gut

You are more likely to develop Type 1 diabetes in the winter months than in the summer months. In another part of this series, we looked at the lack of vitamin D in the darker winter months as a possible cause of Type 1 diabetes.

But what about infections? We all know that we get more infections in the winter months. Could it be that viruses directly attack insulin-producing tissue? Or is it also likely that our immune system causes an abnormal response to an infection? This abnormal response then produces the autoantibodies that destroy the pancreatic cells. The body can then not make insulin.

It is an active area of research. The viruses that are most strongly suspected as being a cause of Type 1 diabetes are those called enteroviruses. Enteroviruses live in the intestine. They are found in biopsy material far more frequently in Type 1 diabetics than those people who do not have the condition. Enteroviruses infections are common in children. Over 100 different types of enteroviruses are known. There is a subset of enteroviruses called coxsackie B viruses, and these are being looked at because they are strongly associated with Type 1 diabetes patients. There is at present a trial underway in Finland to vaccinate vulnerable children. It will be interesting to see the results.

Graph of Milk Consumption


Looking at the graph, it does seem that there is a strong association between Type 1 diabetes and milk consumption.

A study across 12 countries showed that milk consumption per head of population and diabetes rates are strongly associated.

When children from Finland with the same genetic risk of developing Type 1 diabetes were studied, those who drank more than three glasses of milk a day were at higher risk of developing Type 1 diabetes.

But it is never straight forward. Iceland has a higher milk consumption than other Nordic countries but has a lower rate of Type 1 diabetes than them.

Perhaps then it’s the type of milk? What do I mean by this? Milk contains protein. Some of this protein is in a form called casein. Casein comes in 2 types. Casein A1 and Casein A2.  Human milk, goats, sheep, Asian cattle buffalos, and camels have A2 casein. Most modern European dairy cows have A1 casein.

It is the A1 casein that has been thought to be associated with Type 1 diabetes, but no specific trials on humans have ever been done. But mice that have been bred to be susceptible to Type 1 diabetes developed Type 1 when fed A1 milk but not A2 milk.

There is a trial underway in children of high genetic risk of Type 1 diabetes called the TRIGR trial. It is testing the idea that avoiding A1 milk in the first few months of life might reduce the risk of getting Type 1 diabetes. This is based on a pilot study in which there was a 50% reduction in the autoantibodies associated with a risk of Type 1 diabetes. This was not a 50% reduction in Type 1 diabetes. You can, of course, imply that there is an association between autoantibodies and Type 1 diabetes. But also bear in mind that some people can develop Type 1 diabetes without having a single autoantibody.  Interestingly, if the A1 proteins are smashed up or hydrolysed, the problem does not seem to exist. So this would suggest that it is the whole A1 protein that might be causing the problem.

 Another common food that is associated with Type 1 diabetes is wheat.  In part, this is because people with Type 1 diabetes also have coeliac disease, which is caused by allergy to wheat proteins, called gliadins. There have been studies of biopsies of the bowel of  Type 1 diabetes children who have been fed wheat gliadin. There were increased numbers of inflammatory immune cells found in children with Type 1 diabetes, compared to children who did not have Type 1 diabetes.

Also, it has been found that children with autoantibodies making then susceptible to Type 1 diabetes had improved response to sugars in their diet after a gluten-free diet. So that is interesting. However, there were no changes in the number of autoantibodies. This would suggest that gluten-free diets might improve sugar management but would seem from this study to have little effect on stopping the progression to the disease.

 No medical article these days would be complete without a mention of the microbiome. The microbiome consists of billions of many different types of bacteria that are found in and around our bodies. It is often quoted that there are ten times more bacteria than there are human cells in our bodies. We are interested in the gut microbiome in this article. The relationship between food, the microbiome, the intestinal tissue, and the immune system is such that the interaction between all of these different elements is what ultimately determines our health.

Interest took off when it became possible to sequence the genes of bowel bacteria rapidly. We know that there are thousands of bacterial families. The presence or absence of these, and their ratios, seems to be linked with our diet and lifestyle. An extreme example of this is the faecal transplant. People with life-threatening severe diarrhoea on one day have left the hospital the next day entirely well after receiving an enema of a healthy person’s poo. Yes, someone else’s poo was squirted into another’s bottom as a therapy. It’s called faecal transplant therapy in polite circles.  We have been trying to manipulate the microbiome in a more socially acceptable way with probiotic drinks. Of course, the microbiome is a science that is in its infancy. The same samples sent to different labs are not always giving the same results. We need time and experiments to say whether this will be important for people at risk Type 1 diabetes.

One aspect of gut health that might be more promising in the short term is the concept of the leaky gut. It goes something like this.  Some foods do not suit some people and cause the bowel to become inflamed. The gaps between the cells in the colon called zonule proteins are affected. Zonule proteins that join bowel cells together usually are tightly bound together in what are called tight junctions. These tight junctions stop food products from getting out of the bowel and escaping into the bloodstream. Inflammatory foods cause a breakdown of the tight junctions and allow tiny gaps in the bowel wall to exist. These gaps enable food products to get into the bloodstream where they should not usually be. This sets up inflammation, which leads to the production of immune agents. Some of these immune agents can be autoantibodies that are harmful to the pancreas. These autoantibodies can then cause Type 1 diabetes.

 It is all speculation. But some exciting work is being done. A small group in Hungary has devised a technique where they can directly measure a leaky gut. They have designed an anti-inflammatory diet. It is mostly meat-based, with only meat from animals on non- managed pasture, a few vegetables with no pesticide or herbicide residues, and water. It is a specialised diet, but this team has written up a case of prolonged remission in a child with Type 1 diabetes, with some recovery of their insulin production. Ok, this is a single case, but others are being reported.  It does seem to link with other theories around diet that may play some part in the development of Type 1 diabetes.

In summary, there are many ideas about what causes Type 1 diabetes. There are as yet no single theories that explain everything. There are examples of people with Type 1 in every current theory who do not fit the model. Autoantibodies are the current in vogue theory for how Type 1 diabetes starts. But even that theory has exceptions. How do you explain Type 1 autoantibody-negative people?

In the meantime, we can only keep the research going, stay open-minded. In the future, other ideas will develop. Until we have genome sequencing, there was effectively no microbiome. Before satellites, we had not the faintest idea that the Sahara Desert was an essential source of nourishment for the Brazilian rainforest. There is a way to go yet before we find the answer, but there are many great minds determined to work it out. Let’s hope for sooner rather than later.

 So, what to do to avoid Type 1 diabetes?

Well, make sure you are born without risky genes.

 Make sure that you arrange your birth close to the equator.

 Ensure that throughout your life that your cells multiply with no mistakes ever.

 Get plenty of sunlight.

Eat food that keeps your microbiome healthy.

Eat food that stops you from making autoantibodies. Avoid wheat, drink milk that is A2, or hydrolysed.

Don’t get a Coxsackie B infection.

Add the words ‘possibly’ and ‘in some cases’ to every one of the above sentences. And hope that our scientists come up with something soon.

 In the meantime, adopt a low carb lifestyle, and make sure that you include all of the known lifestyle practices that will help you to manage your Type 1 diabetes to the max.  Food, physical activity, stress management, and sleep play a part in that success. And if an when a cure does come, they will remain the cornerstones of management. After all, it’s the recipe for a healthy life, diabetes or not.