What Causes Type 1 Diabetes? These 4 Researched Theories Will Blow Your Mind...

Type 1 Diabetes mellitus is identified as an autoimmune disease and the way it occurs is not yet understood but involves many hypotheses. A lot of studies have demonstrated that environmental factors play a major role in T1DM pathogenesis leading to a complete destruction of βcells of the pancreas in susceptible individuals. It is believed that there may be an overlapping between these various hypotheses and that’s why the incidence rate is increased year by year.  

HYPOTHESES: 

1. Hygiene Hypothesis: 

One of the most credited hypothesis. It is suggesting that exposure to many infections and pathogens during childhood makes immunity more adjusted by the action of competition for the immune cells. Making the auto-reactive T cells unavailable from the site of autoimmunity due to the infection. Or you can say it’s like keeping your immune system busy fighting the bad guys (pathogens and microbes) more than fighting the good guys (Yourself). Therefore we can hypothesize that stronger immune responses, in this case anti-infectious, will compete for homoeostatic signals against weaker responses, such as those against autoantigens; making the immune system. 

So the question is does the early exposure to germs and microbes in children decrease the incidence rates in autoimmune diseases? 

Many studies have reached the conclusion that certain bacteria and germs presence is being associated with an immune system functioning in a healthy way. But through the industrial revolution, some changes in sanitation standards like (pasteurization, vaccination, antibiotic use, ..etc) resulted in an increase of incidence of the autoimmune disease including type 1 diabetes. 

2. Molecular Mimicry: 

The protein sequence of foreign invaders and self-cells can somehow look quite similar to results in something called cross-activation of T or B cells against these peptides. The viral peptides on the βcells of the pancreas can somehow be recognized as non-self, making your immune system quite confused of this similarity. Thus resulting in a huge attack against BOTH peptides.  

Studies have reported an increase in the number of enterovirus (Coxsackie B4 virus) infections in pre-diabetic children associated with an increase in the levels of viral RNA and autoantibodies. 

Usually, the symptoms of Coxsackie B virus infection includes fever, pericarditis and myocarditis in children. 

Also, other viruses may also play an elusive role like Mumps, Rubella, Cytomegalovirus and Rotaviruses. 

Of course, these findings suggested a question worth-answering: 

Will a coxsackie B virus vaccine prevent the occurrence of type 1 diabetes? 

3. Vitamin D deficiency

Vitamin D plays a major role in the modulation of innate and adaptive immunity but its specific mechanism is not quite clear. So some studies attribute the T1DM incidence to the seasonal and geographical exposure to UV light. Some of these studies suggested that higher vitamin D levels during childhood were linked to a lower risk of developing autoantibodies that mainly results in type 1 diabetes in susceptible individuals. Therefore recommendations are getting stronger for Vitamin D supplementation in children before the age of 5 especially in the winter and autumn months where sun exposure is minimal. 

4. Breastfeeding Vs cow milk

Without any doubt, natural breastfeeding is considered the best option for infants and newborns. Breast milk contains a lot of molecules that help the newborns fight infections and autoimmunity for example the secretory IgAs and lactoferrins that help the body fight many bacteria and it also contains insulin and other types of immune cells. While on the other hand, cow milk has different constitutional values than breast milk to help the calves grow and this can be unhealthy to human consumption leading to weight gain that can lead to developing diabetes. 

Cow’s milk may be considered as a triggering agent due to molecular mimicry and growth factors. 

Some studies have suggested that cow's milk exposure causes a bovine insulin-induced immune response. (Molecular mimicry) 

Let’s keep in mind that Cow milk is good for calves and human breast milk is good for humans. 

Balance shift: All of these hypotheses can be classified as either 

1. Diabetogenic that includes (Viruses, Cow’s milk, Vit D deficiency) 

2. and Protective (Vit D, pathogens and breast milk) 

It’s believed that in healthy individuals a balance between them is maintained while in patients developing T1DM, a shift towards diabetogenic factors occurs thus resulting in the combination of all of these factors and making the “autoimmune” phenomenon happen in susceptible individuals resulting in the complete destruction of insulin-producing cells and the complete dependence on insulin injections. 

“Why these susceptible individuals and not anyone else?!” is a question that unfortunately cannot be answered to this day but huge research is taking place to find the answers. 

Nada Sami is a fresh graduate of clinical pharmacy and a type 1 diabetic patient for more than 20 years. She is interested in the field of autoimmunity due to her diabetes, that made her the person she is today. Her career mainly involves educating and counseling patients about their medications and diseases as well.