Under is an approximation of this video’s audio content material. To see any graphs, charts, graphics, photographs, and quotes to which Dr. Greger could also be referring, watch the above video.
Intro: As many as 37 p.c of breast most cancers instances could also be attributable to publicity to bovine leukemia virus, which I first did a sequence about years in the past. On this two-part sequence, I evaluation the science behind this phenomenon and replace it with the more moderen information. To see the unique sequence, try the physician’s word for this video.
The incidence of breast most cancers is repeatedly rising worldwide. Within the U.S., this amounted to a 40 p.c improve within the incidence by the flip of this century. At the moment, the primary method is early detection and therapy. That’s necessary, however why not pay extra consideration to main prevention; in different phrases, defending individuals from being uncovered to danger elements for breast most cancers in order that they by no means develop breast most cancers within the first place?
“General, it’s estimated that 20 p.c of all human cancers have an infectious origin.” Viruses can set off most cancers by turning on most cancers genes or turning off most cancers suppressing genes, however they will additionally contribute to tumor formation simply by inflicting persistent irritation. At the moment, cancer-causing viruses are thought-about the main believable speculation for a direct reason behind human breast most cancers. How did we get right here?
It began about 40 years in the past when a professor of virology at UC Berkeley realized how mouse mammary tumor virus was found. Scientists swapped child mouse pups from mice with a excessive incidence of mammary most cancers with pups from mouse strains with a low incidence, and located that the most cancers incidence matched the foster moms, displaying it wasn’t genetic. “It occurred to me,” the professor thought, “that people are foster-nursed on the cow.”
Bovine leukemia virus (BLV) had simply been recognized as a cancer-causing cow virus. On the time solely about 1 in 10 U.S. dairy cows had been contaminated, however now it’s nearer to half. We began out with 2/3s of herds affected. Then, it was extra like 80 p.c, based mostly on their milk testing constructive for the virus, and one hundred pc of the herds within the bigger industrial farms. And now, greater than 9 out of 10 U.S. herds are affected, a continuation of the historic pattern of the persistent proliferation of BLV inside U.S. dairy herds.
We’ve lengthy recognized that nations with the very best milk consumption additionally had the very best breast most cancers incidence. And it’s not only a matchup between dairy consumption and breast most cancers incidence on the nation degree. Particular person ladies who’re lactose illiberal and eat much less dairy additionally appear to have decreased danger of breast most cancers. Oh, however come on, there’s a lot of stuff in milk that may very well be contributing to the most cancers danger, like saturated fats and the presence of cancer-promoting development hormones, like IGF-1.
Sure, we all know bovine leukemia virus is current in marketed beef and dairy merchandise. About half of milk and meat samples flip up constructive for the virus. In truth, you’ll be able to pattern the virus straight out of the air on dairy farms, on surfaces, and within the milk itself. Most milk is pasteurized, however many dairy merchandise, like uncooked aged cheeses are usually not. And who hasn’t eaten a pink-in-the-middle hamburger sooner or later of their life?
Sure, we have now proof that individuals are uncovered to the virus. Sure, we have now proof that individuals are actively contaminated with the virus. But it surely wasn’t till 2015 that we realized an infection charges had been highest in cancerous breast tissue, a lot in order that as many as 37 p.c of breast most cancers instances could also be attributable to publicity to the bovine leukemia virus. That was sufficient for me to set off an entire sequence of movies on the position the virus performs in breast most cancers, and the way the meat and dairy industries responded to the information. Okay, now that we’re all again up to the mark, what’s the most recent replace? That’s what I’ll cowl subsequent.
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