What Triggers Type 1 Diabetes?

In the 1980s, there was a lot of excitement among researchers about studies showing that kids who ate cow’s milk-based foods at a very young age ran a higher risk of developing T1D. One long-term study tested the idea that weaning infants to a special kind of formula would reduce the risk. Alas, that didn’t work!

But the role of cow’s milk is still being investigated. There is also some evidence linking cereals, gluten (wheat protein), root vegetables, and omega-3 fatty acids to an elevated risk of T1D.

Also, as noted above, some studies indicate that people who get more vitamin D from sunshine are less prone to T1D. Dan Hurley calls this theory “the sunshine hypothesis” in his very enlightening book, “Diabetes Rising.”

If that’s true, would you take vitamin D supplements to help prevent the disease? A review of relevant research in Lancet notes that “there is surprisingly little supporting evidence” for this idea.

Unfortunately, we’ve just scratched the surface here, as scientists are still investigating a whole array of other factors that might also influence the development of T1D:

•  frequent early childhood respiratory or gastrointestinal infections

•  Rapid growth and weight gain in children

•  low physical activity during puberty

•  trauma or serious life events, such as divorce or death in the family

•  stress (via increased cortisol concentrations)Weakened immune systems?

While trying for decades to identify the risk factors for T1D, scientists have also been struggling to understand its underlying causes and why its incidence is increasing, especially in developed countries.

One idea that got tons of publicity in the 1990s is the “hygiene hypothesis,” which proposes that people in the developed world are too clean for our own good. The idea is that advanced sanitation has weakened our immune systems because they no longer have to fight off so many germs and infections. So instead, the theory proposes, the immune system goes haywire and attacks healthy cells in the body.

There hasn’t been conclusive evidence to support a direct connection between improved hygiene and T1D, but one current hypothesis is a closely related notion. It poses that as children, we need to be exposed to a broad range of little microbes to teach the immune system to distinguish between the body’s friends and foes. If kids don’t get enough contact with these harmless microorganisms that have been present throughout human evolution, their immune systems may not get properly trained. And one consequence could be T1D.

There is also emerging evidence of a link between the so-called “microbiome” — the tiny organisms inside of the gut — and T1D. Scientists pose that people might need the right combinations of these little organisms for the immune system to function properly and not turn against insulin-producing cells.

None of this is yet conclusive, so the quest to understand why T1Ds’ immune systems are compromised continues.

Unfortunately, no one has come up with a unified theory that convincingly explains the possible interactions between genes, viruses, the environment, diet, microbes, and other potential contributors to T1D. Without nailing the causes, science hasn’t been able to offer us convincing steps people can take to prevent T1D. Not yet, that is.

Two long-term studies are underway to sort some of this out. The first is called TrialNet, a network of leading T1D research clinic sites around the world that is testing children who are a direct relative of someone with T1D — a parent, sibling, aunt, uncle, cousin, or grandparent — to learn about how this disease may be inherited.

The second is called The Environmental Determinants of Diabetes in the Young (TEDDY) study, which is keeping track of children with genetic markers of T1D and trying to determine what prompts some of them to get the disease while others remain diabetes-free.

Let’s keep hoping that researchers will eventually unravel the mystery of what causes T1D. That might help them come closer to finding a way to prevent and even cure it.