“Nearly 20% of cancer cases arising worldwide can be linked to infectious agents, including viruses.” Seven viruses are actually conclusively tied to human cancers, and, as new viruses enter into human populations, the incidence and causes of most cancers will possible change accordingly.
The basis of fashionable tumor virology was laid greater than a century in the past with the invention of a cancer-causing hen virus, for which a Nobel Prize was awarded. Another Nobel Prize went to the “medical doctor-turned-virologist” who found that the HPV virus was inflicting cervical most cancers. In his acceptance speech, he mused that there could also be a bovine polyoma virus—a a number of tumor virus in cattle—that might be taking part in a task in human colon most cancers, lung most cancers, and breast most cancers, however no polyoma virus had ever been found in meat…till now.
As I talk about in my video The Role of Burger Viruses in Cancer, polyomaviruses are a selected concern—not solely as a result of they’re recognized to be carcinogenic, but additionally as a result of they’ll survive cooking temperatures. Since a single burger nowadays can include meat from “many dozens of animals,” researchers felt “this could present an ideal situation for virus-hunting…” Researchers from the National Cancer Institute bought meat samples from three separate supermarkets and discovered three completely different polyomaviruses in floor beef, as you may see at 1:52 in my video. Now, simply because three varieties of “polyomavirus species are commonly detectable in food-grade ground beef” doesn’t essentially imply they’re inflicting human illness. What made this Nobel laureate suspect them? Well, for one factor, some individuals received most cancers proper the place that they had been vaccinated for smallpox—an entire bunch of completely different cancers, in truth. The vaccine had been harvested from the pores and skin of calves, so “it is possible” there might have been some cancer-causing cow virus.
“Many people are exposed to potentially virus-contaminated meat and dairy products” by way of their diets, however these in the trade, “such as farm workers, butchers, veterinarians, and employees in dairies,” could be much more uncovered. Do these teams have larger most cancers incidence? Indeed, it now seems to be clear “that workers in the meat industry are at increased risk of developing and dying from cancer.”
Another purpose to suspect the involvement of some type of bovine infectious issue in colorectal most cancers is the truth that there look like comparatively low charges of colorectal most cancers in international locations the place not lots of beef is eaten. And, when meat consumption instantly will increase, charges shoot up, as you may see at 3:15 in my video. “The only exception is Mongolia where they have low rates of colon cancer and eat a lot of red meat, but there they eat yak.” Maybe yaks don’t harbor the identical viruses.
Can’t you simply keep away from steak tartare? Even steak cooked “medium” might not attain inside temperatures above 70° Celsius, and it takes temperatures larger than that to inactivate some of these viruses, so we’d anticipate viruses to outlive each cooking and pasteurization. In truth, researchers adopted up with a paper suggesting the consumption of dairy merchandise might “represent one of the main risk factors for the development of breast cancer” in people. The current discovery of a bigger quantity of presumably new viruses in the blood, meat, and milk of dairy cows needs to be investigated, since one may speculate that infectious “agents present in dairy products possess a higher affinity to mammary [breast] cells,” since they got here from breast cells. The truth that folks with lactose intolerance, who are likely to keep away from milk and dairy all through their lives, have decrease charges of breast and different cancers might be seen as supporting this idea. Though, there are definitely different causes dairy might improve most cancers threat, reminiscent of growing ranges of the cancer-promoting development hormone IGF-1 or adversely affecting our intestine microbiome. Or, for that matter, perhaps the plant-based milks they’re ingesting as an alternative might be protecting. That’s the issue with inhabitants research: You can’t tease out trigger and impact. It doesn’t matter what number of viruses are discovered in retail beef, pork, and hen, as you may see at 5:16 in my video, if we will’t join the dots.
Can’t we simply search for the presence of these viruses inside human tumors? Researchers have tried and did discover some, however even in case you don’t discover any, that doesn’t essentially imply viruses didn’t play a task. There’s a “viral hit-and-run” idea of most cancers improvement that means that sure viruses can slip in and out of our DNA to provoke the most cancers, however be lengthy gone by the point the tumor matures.
There’s nonetheless lots of work to be accomplished. But, if the link between bovine polyomaviruses and human illness pans out, the National Cancer Institute researchers envision the event of a excessive efficiency vaccine. So, identical to the HPV vaccine might forestall cervical most cancers from unsafe intercourse, maybe at some point, vaccines might forestall breast and colon most cancers from unsafe sirloin.
This jogs my memory of the story of bovine leukemia virus and breast most cancers. For extra on that, see:
What about hen? Check out The Role of Poultry Viruses in Human Cancers and Poultry and Penis Cancer.
One of the issues with eating different animals is that we put ourselves in danger of their illnesses. Not as soon as have I recognized anybody with Dutch Elm Disease or a extremely unhealthy case of aphids. See Eating Outside Our Kingdom for extra on this idea.
Michael Greger, M.D.
PS: If you haven’t but, you may subscribe to my free movies right here and watch my dwell shows: