Which Has a Greater Impact on Type 1 Diabetes Development: Genes or Environment

Many people are convinced that type 1 diabetes (T1D) is solely a genetic cause.

While others believe it only relies on one’s environmental and inflammatory triggers.

The quick answer is that BOTH genes and the environment are typically at fault.

Keep reading to find out how these two factors influence each other and type 1 diabetes development.

Environmental Influence – When There’s No Family History of Diabetes

Many type 1 diabetics, especially those with a family history of T1D, are convinced their genetics are the sole reason for their condition.

It doesn’t help that various healthcare providers repeat this notion, as well.

Genes can play a part in disease development and I’ll elaborate further on this in a moment.

But what about people like me?

No one in my immediate or extended family has ever had any history of any kind of diabetes.

In addition to that, before my T1D diagnosis, I’d always been the most athletic among my siblings.

So what gives?!

I know there are a great number of other type 1 diabetics thinking the same thing.

One particular study notes that since pancreatic beta cell autoimmunity is often seen during the first 6 years of life, there may be other environmental factors influencing the progression towards type 1 diabetes (1).

These pancreatic β-cells are where insulin is produced. Attack on these cells is the foundation of type 1 diabetes.

These researchers suggest birth delivery mode, early diet, infections, and antibiotic use may all have associations with type 1 diabetes diagnosis.

It’s interesting to note that these suspected type-1-diabetic triggers also influence gut dysbiosis.

In part 1 of this series, I went over that to be diagnosed with type 1 diabetes, the immune system needs to attack and, pretty much, obliterate the beta cells that produce insulin in the pancreatic islet cells.

Animal and human studies have been able to show strong relationships between the gut microbiome and pancreatic beta cell autoimmunity (2).

One animal study was even able to find associations between a weakened gut barrier and bad gut bugs escaping to plant themselves within the pancreatic lymph nodes, causing inflammation to the pancreatic islet cells (3).

This was mind-blowing to me when I first read this!

Now, if a particular illness runs rampant within the same family tree, it would be safe to assume that there is a strong genetic tendency influencing this.

However, if this same family is practicing unhealthy lifestyle choices or has fallen victim to some of the aforementioned triggers throughout this series of posts, then genetics may not be the sole culprit to blame.

Let’s elaborate on this more.

Genetic & Environmental Estimates + More Gut Dysbiosis Research

The former director of the US National Institutes of Health (NIH), Dr. Francis Collins, once said “Genetics load the gun and environment pulls the trigger.”

In other words, the approximation of genetic and environmental influence on acquiring an autoimmune disease, such as type 1 diabetes is (4, 5, 6):

10% genetics
90% environmental triggers

This whole series of posts go over at length the most common environmental triggers that normally affect our gut microbiome.

This study suggests gut dysbiosis is involved at two different times during the pathogenesis of type 1 diabetes, specifically in infants (7).

The first incidence is when the intestine is overpopulated with pathological microbes, influencing the immune system to dysfunction.

As a result, the infant’s susceptibility to autoimmune diseases increases.

The second incidence notes that gut dysbiosis can be seen before diabetes-associated antibodies become present in blood tests.

The study also reiterates intestinal and immune improvements made by giving the infant probiotics.

With all this environmental info being noted, how do genetics play its role in type 1 diabetes?

Genetic Influence

For the genetic 10% that influence type 1 diabetes development, it should be known that the human leukocyte antigen (HLA) class II genes are the strongest genetic risk factors for inheriting T1D.

HLA genes are involved in many immune responses.

Specifically, the HLA class II branches consisting of the haplotypes HLA-DR3-DQ2 and HLA-DR4-DQ8 are the most recognized genetic risk factors for type 1 diabetes (8).

However, one study suggests that less than 10% of those with HLA-conferred risk genotypes develop type 1 diabetes (9).

So, how do you explain the family that has almost all of its members with type 1 diabetes?

Is it possible that this family of genetic codes drew the short end of the stick at every birth and their genetics truly are the sole factor for their immune compromise?

Yup.

Is it likely?

My belief is no, it’s not.

Let me give you an example that everyone is usually familiar with.

We all know of or have heard stories of an individual who lived to be 100 years old, and smoked a pack of cigarettes a day for decades, right?

These people DO exist.

Their lifestyle choice(s) may not appear to affect the longevity of their livelihood, but I would be willing to bet the quality of their lives, especially towards the end, may be something that paints a different picture.

It is possible to smoke a pack of cigarettes a day and live to be 100 years old.

But don’t hold your breath, expecting that to occur.

And don’t bet on these individuals thriving towards their last few years of life, either, even though it is possible.

There is evidence to support associations with, both, altered gut health and genetic predisposition leading to type 1 diabetes (10).

For families who share an abundance of a particular condition(s), they may not be aware of how strongly their environment is influencing much of their health.

If this is the case, I would kindly challenge said family to alter many of their current lifestyle behaviors. These changes would likely positively impact their health and those of their offspring to better results.

Genetic Predisposition& Identical Twin Studies

Genetic predisposition is a medical term meaning the increased likelihood of a particular condition occurring in an individual.

This may be due to a family history of a particular condition(s) being present or by many unknown physiological factors or both! Currently, it’s unclear how genetic predisposition established.

There’s speculation that once genetic predisposition has been “confirmed” in the body, the one factor that has the greatest influence on whether or not a disease occurs is diet.

To provide more evidence as to why genetics, alone, is not likely the only reason for type 1 diabetes development, among other conditions, let’s look at a few studies whose focus is on twins with genetic predisposition to certain conditions.

These monozygotic (identical) twins share the same genes and sex between each other.

So, if there’s a family history of a particular condition, they both should get this condition, right?

Let’s see what the medical research has to say on this.

One specific study researched identical twins with a family history of type 1 diabetes. They found that there was less than a 50% chance for those who were tested to be diagnosed with T1D (11).

Among identical twins and rheumatoid arthritis, it was only 15% (12).

And the largest concordance rate (presence of a focused trait between twins) study with multiple sclerosis found only a 25% likelihood of diagnosis (13).

Which means that if genetic influence doesn’t play as big a role as previously thought, then something else foul is at play in many disease developments, no?

This is why researchers are currently doubling down on the gut microbiome of type 1 diabetics and other illnesses (14).

Genetic Testing

The main takeaway with genetics is that it’s unclear the specific factors that play into the genetic predisposition of particular conditions.

However, we’ve gone over the more common environmental triggers that appear to validate whatever condition(s) the body may be vulnerable to being diagnosed with.

Depending on how long these inflammatory triggers have been present or how sensitive one’s genetic disposition may be (or both), diagnosis of illness may occur earlier for some compared to others.

However, there are particular antibodies specific to diseases that may be tested proactively.

For example, islet cells, parietal cells and intrinsic factor proteins, and thyroid peroxidase enzyme antibodies may be tested to validate if diabetes, pernicious anemia, or thyroid disease may be present leading one to be more vulnerable to either condition(s).

You can get these tests ordered from a physician through Cyrex Laboratories or without a medical professional at 23 and Me (15, 16). Results will likely be better informed through a physician, however.

My Diseases & My Children – Any Risks?

Now, I have had questions come up regarding my type 1 diabetes and celiac conditions and my children.

I’m comfortable in assuming my boys most certainly have a genetic predisposition to both of my conditions and/or other autoimmunity.

It is my firm belief that just because I have type 1 diabetes and celiac disease, my two sons will not be sentenced to this same fate or another condition while under my family’s roof.

And why do I believe this?

As you’ve read throughout this series of posts, environmental factors can heavily influence the cornerstone of our health, specifically the gut!

So, as long as their mother and I expose our boys and their gut flora to the more advantageous variables that enable the best nutrient absorption and the strongest gut barrier possible, I truly don’t worry as much about what may occur with their physiological health.

Sugar intake is also a consideration for them, but their consumed glucose is mostly coming from whole food sources to meet their daily energy demands.

And their young bodies are burning quite a bit of that consumed energy/calories daily!

That being said, it is also my belief that due to our sons’ genetic profile, there’s a good chance that they may be more susceptible to acquiring type 1 diabetes or other autoimmune conditions.

And this may very well increase more if I ignore the research presented in this series of posts, given the repetitive associations we’ve seen!

Time will tell how all this will go down as they get older.

But until then, what do I have to lose?

They’re predominantly eating a nutrient-dense, whole foods diet.

Their guts will be in prime shape, which heavily favors all the benefits we’ve gone over.

I’m confident my boys will be alright as long as we focus on optimizing their gut health. Again, time will tell.

Something Every Type 1 Diabetic Needs to Know!

Shockingly, many diabetic physicians are not discussing their patient’s gut health more within their practices.

Based on the medical literature we’ve reviewed; doesn’t it make sense to at least consider our gut health playing a role in our overall well-being, possible disease prevention, and better diabetic management?

Although there is more that needs to be understood about the direct pathogenesis of type 1 diabetes, there’s just too much evidence that exists to not at least consider the physiological benefits we’ve gone over associated with gut health and type 1 diabetes.

I know…I know…

As bold as this statement may sound, the trend of research supporting this is just too overwhelming to ignore.

I strongly urge all type 1 diabetics to ask their physicians about their gut health!

Maybe even do a bit of your own research, as well?

My own experiences with optimizing my gut health have:

-greatly reduced my insulin demand

-increased my insulin sensitivity

-enabled me to predict better what my blood sugars will be given certain actions, i.e. activity, diet, sleep, and stress.

Most importantly, I do feel more in control of my diabetes and my life. Whereas I see many others “shackled” to a ball and chain with theirs.

My goal is to empower you with what some of the medical research has provided on these topics mainly because I do feel it would benefit many of you to at least know of other therapeutic modalities that have a pretty good track record under the right medical circumstances.

Like what you read? Share it with a friend whom you feel may benefit with this information.

Summary

Most diseases and illness can attribute their conditions accordingly: 90% Environmental triggers and 10% genetics
Incidentally, most of the same environmental triggers can also affect gut health, too
Some research suggests that gut dysbiosis is involved at two different times during type 1 diabetes development:
1. When the intestine is overpopulated with bad gut bugs, which reduces proper immune function
2. Just before diabetes-associated antibodies become present in blood tests
Some research papers show minimal genetic influence on the cause of illnesses children may get due to their parent(s) having the same condition, type 1 diabetes included

References

Empower Your Blood Sugars to Overcome their Most Common Hurdles!

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The most common type 1 diabetic frustrations
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