Does Paratuberculosis in Milk Trigger Type 1 Diabetes?

Type 1 diabetes “arises following the autoimmune destruction” of the insulin-producing cells of the pancreas. It’s “often diagnosed in children and adolescents,” who usually present with “a classic trio of symptoms”—excessive thirst, hunger, and urination—as their blood sugars spike. And, they need to go on insulin for the rest of their lives, since their own immune system attacked and destroyed their own ability to produce it. What would cause our body to do such a thing?

Whatever it is, it has been on the rise around the world, starting after World War II. “Understanding why and how…the [current] pandemic of childhood diabetes” was produced “would be an important step toward reversing it.” A plausible guess involves so-called “molecular mimicry,” whereby a foreign antibody generator (like a bacterium or virus) “provokes an immune response, which cross-reacts with a similar”-looking protein on our own pancreas—such that when we attack the bug, our own organ gets caught in the cross-fire.

Okay, so, what pancreatic proteins are type 1 diabetics self-attacking? In the 80s, a protein was identified, which, in the 90s, we realized looked an awful lot like a certain mycobacterial protein. Mycobacteria are a family of bacteria that cause diseases like tuberculosis and leprosy. And, all newly diagnosed type 1 diabetic children were found to have immune responses to this mycobacterial protein. But, that didn’t make any sense. I mean, type 1 diabetes is going up in the industrialized world, where TB and leprosy rates are going down. Well, there is one mycobacterial infection in livestock that’s shot up with the industrialization and globalization of animal agriculture—called paratuberculosis—which causes Johne’s disease in animals, now recognized as a global problem for the livestock industry.

Huh, weren’t there like a dozen studies suggesting that exposure to cow’s milk may be “an important determinant of subsequent type 1 diabetes” in childhood? Putting two and two together, an idea was put forward in 2006. Could mycobacterium paratuberculosis be a “trigger” for type 1 diabetes? It was a compelling enough idea that researchers decided to put it to the test.

They attempted to test the association of MAP, the full name for the bug—mycobacterium avium paratuberculosis—with type 1 diabetes, by testing diabetics for the presence of the bacteria in their blood. And, lo and behold, most of the diabetic patients were found positive for the bug, compared to only a minority of the healthy control subjects. This evidence of MAP bacteria in the blood of patients with type 1 diabetes “might provide an important foundation in establishing an infectious” cause for type 1 diabetes. “These results…might have…implications for countries that have the greatest livestock populations and [a] high incidence” of both MAP and diabetes, like the United States. Johne’s disease is what you call the disease when livestock get infected by the bug. The reason the researchers chose Sardinia, an island off the coast of Italy, is because “[p]aratuberculosis is present in more than 50% of Sardinian herds.”

If they think that’s bad, the last national survey of dairy herds in the U.S. shows 68% are infected with MAP, especially those big industrial dairies. 95% percent of operations with more than 500 cows came up positive. It’s estimated the disease costs the U.S. industry more than a billion dollars a year.

How do people become exposed? “The most important routes of access of MAP [in]to the [human] food chain appear to be contaminated milk, milk products, and meat from infected [cattle, sheep, and goats]. …MAP or MAP DNA [has been] detected in raw milk,…pasteurized milk,…infant…formula,…cheese, ice cream,…muscle and organ tissues…and retail meat.”

How do we know paraTB bacteria survive pasteurization? Because Wisconsin researchers bought hundreds of pints of retail milk off store shelves from three of our top milk-producing states, and tested for the presence of viable (meaning living) MAP bacteria in retail milk. And, 2.8% came back positive for live paraTB bacteria, with most brands yielding at least one positive sample. So, it can survive pasteurization.

If paraTB does end up being a diabetes trigger, then “these findings indicate that retail milk [in the United States] would need to be considered as a transmission vector.” Why hasn’t the public heard about this research? Perhaps because the industry isn’t too keen on sharing. This is from the Journal of Dairy Science: “Fear of consumer reaction can impede rational, open discussion of scientific studies.”

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