A higher rate of cancer deaths among those that handle and process meat is attributed to infection with viruses and chronic exposure to animal proteins.
Although slaughterhouse workers with the most poultry exposure appear to suffer the greatest excess mortality, increasing risks of death from cancer are also found in other slaughterhouse workers.This research goes back decades and shows higher cancer rates in butchers, slaughterhouse workers, meat cutters, and those working in meat processing plants. The bottom line is that it's clear from this large study and many others that workers in the meat industry are at increased risk of developing cancer and dying from it.
The increased risk may be due to animal-to-human viruses or antigenic stimulation through chronic exposure to animal protein. And in fact, cancer-causing virus exposure could help explain why those who eat meat have higher cancer rates. There's even a retrovirus associated with cancerous fish tumors, which has been speculated as the cause for increased cancer rates in American seafood workers.
Growing up on a livestock farm is associated with higher rates of blood-borne cancers—lymphomas and leukemias- but growing up on a farm raising only crops is not.
Worst is growing up on a poultry farm, which is consistent with chicken consumption being most closely tied to these cancers. A quarter of a daily chicken breast is associated with a doubling or tripling of risk of these cancers.
Researchers are finally able to start connecting the dots. High levels of antibodies to avian leucosis/sarcoma viruses, and reticuloendotheliosis viruses recently found in poultry workers provides evidence of infectious exposure to these cancer-causing poultry viruses. And the highest levels were found not in the eviscerators, or gut-pullers, or those that hang the live birds, but among the line workers that just cut up the final product.
In an attempt to narrow down which diseases were associated with which meat, researchers tried separating out those in pig slaughtering and pork processing. One of the primary sources of concern in using pig organs and tissues as transplants in humans (this is widely practiced) is the fear of introducing zoonotic infections from animals. They're concerned about what's called PERV transmission, the pig-to-human transmission of porcine endogenous retroviruses, raising theoretical concerns about cancer, immunological, and neurological disorders. However, you don't need to get a pig transplant to be exposed. They’re also found in blood, so people exposed to pig blood may be exposed to the virus.
The main finding unique to the pork study, which was not found in beef and sheep processing, was the significant excess deaths from senile conditions such as Alzheimer’s disease. It reminds me of all those poor pork brain extraction workers. You think your job is bad, how would you like to work at the head-table—well, that doesn't sound so bad, until you learn it's where, in the unbridled use of compressed air in the pursuit of maximum yield of soft tissue, they blow the brains out of severed swine heads.
"As the line speeds increased, the workers reported being unable to place the skulls completely on the brain removal device before triggering the compressed air, causing greater splatter of brain material”. The aerosolized "mist of brain" is suspected to be the cause of dozens of cases of inflammatory neurological disease in workers who started with symptoms as mild as pain, tingling and difficulty walking and ended up as bad as doctors having to put them in a coma for 6 weeks because of unrelenting seizures.
At first they thought it was a brain parasite, but now it's known to be an auto-immune attack triggered by the exposure to aerosolized brain. A similar mechanism has been blamed for meat proteins triggering inflammatory arthritis in people eating meat. By eating fellow animals, we are exposed not only to fellow animal diseases, but to animal tissues that our body may mistake as our own. This may be one advantage to eating a more plant-based diet. By eating outside of the animal kingdom—dipping into the plant kingdom or fungi like mushrooms- not only do you not have to worry about getting something like Dutch elm disease, but never has an auto-immune polyradiculoneuropathy been blamed on a head… of lettuce.
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 Ariel Levitsky.
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See the last video Poultry Exposure Tied to Liver and Pancreatic Cancer for the data on poultry exposure and cancer deaths.
Though exposure to farm animals growing up might be associated with cancer risk, what about growing up with dogs and cats? See Pets & Human Lymphoma and Are Cats or Dogs More Protective for Children’s Health? You still probably shouldn't eat them, though (see Foodborne Rabies).
For more on foodborne illnesses one can contract from fellow animals, see, for example:
Probably the strangest example of this whole concept is the Neu5Gc story. A 7-part video series definitely worth checking out:
For more context, check out my associated blog posts: Handling Poultry Tied to Liver/Pancreatic Cancer and How Animal Proteins May Trigger Autoimmune Disease.
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