Transcript: Alpha Gal and the Lone Star Tick
In the beginning, Aristotle defined two forms of life on planet Earth: plants and animals. 2000 years later, the light microscope was invented and we discovered tiny, one-celled organisms like amoebas. Then, the electron microscope was invented and we were better able to characterize bacteria. Finally, in 1969 biologists recognized fungi as a separate category and we've had at least five kingdoms of life ever since.
In my video, Higher Quality May Mean Higher Risk, I talk about the potential downsides of consuming proteins from within our own kingdom, because of the impact our fellow animal proteins can have on boosting our liver's production of a cancer-promoting hormone called IGF-1.
In Eating Outside Our Kingdom, I talked about other potential advantages of preferably dipping into the plant and mushroom kingdoms for dinner, not only from a food safety perspective—we're more likely to get infected by animal pathogens than Dutch Elm Disease, but because of the potential for cross-reactivity between animal and human proteins. Our immune system is more likely to get confused between this and this, rather than this and that, and so there may be less potential to trigger an autoimmune reaction, like the degenerative brain diseases I talked about. Same concept with animal proteins triggering inflammatory arthritis. In attacking some foreign animal meat protein, some of our own similarly composed tissues may get caught in the crossfire.
And it's not just proteins. If you remember the Neu5Gc story, there's this sialic acid in other animals that may cause inflammation in our arteries and help breast tumors and other human cancers to grow.
Well now a new twist has been added to the story. The reason NeuGc triggers inflammation is because humans lost the ability to make it two million years ago, and so when our body is exposed to it through animal products, it's treated as a foreign invader. Well there's another oligosaccharide called alpha-gal that we, chimps, and apes lost the ability to make 2 million years ago, but is still made by a variety of animals, including many animals we eat.
Alpha-gal antibodies may be involved in a number of detrimental processes that may result in allergic, autoimmune and “autoimmune like” diseases, such as auto-immune thyroid disorders. You see higher levels in Crohn’s disease victims; they react against about half of human breast tumors and you can even find antibodies to this stuff in atherosclerotic plaques in people's necks, but those are all mostly speculative risks. We do know alpha-gal is a major obstacle to transplanting pig organs into people, like kidneys, because our bodies reject alpha-gal as foreign. It's considered the major target for human anti-pig antibodies.
It's interesting if you look at those that abstain from pork for whatever reason, they have fewer swine-specific white cells in their bloodstream, speculating that oral intake of pork could ferry swine molecules into the bloodstream via gut-infiltrating lymphocytes to prime the immune response.
So you can certainly have an allergic reaction to eating the kidneys too, but such severe meat allergies were considered rare, until an unusual report surfaced. First described in 2009, the report included details on 24 cases of meat allergies triggered by tick bites. Within a year, it was obvious that the cases should be counted in hundreds rather than dozens. By 2012, it was clear that there are thousands of cases across a large area of the southern and eastern U.S., and now present in several countries around the world.
The lone star tick, so-called because females have a white spot on their back. They're famous for causing Masters' disease, a lyme-disease like syndrome, also known as STARI, Southern tick associated rash illness. But thanks to the lone star tick steadily expanding its range, it's not necessarily just so Southern any more.
Ok, but what is the relevance of tick bites to the production of anti-meat allergy antibodies to alpha-gal? Good question. What we know is you get bit by one of these ticks, and you can develop an allergy to meat. This appears to be the first example of a response to an external parasite giving rise to an important form of food allergy, either because there's something in the tick saliva that's cross-reacting with the alpha-gal, or because the tick is like injecting you with animal allergens from its last meal.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.
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