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  • Writer's pictureOrina Ontiri

Breast Cancer Linked to Cattle Virus (confirmed)

breast cancer blv virus

A new study of 239 breast tissue biopsies report a 3.1 times higher presence of a common cattle virus (BLV) in the cancerous vs. noncancerous tissues.

The CDC (centers for disease control) states that this extremely common cattle virus, ‘Bovine Leukemia Virus’ (BLV) is prevalent in “38% of beef herds, 84% of all dairy herds, and 100% of large-scale dairy operation herds worldwide.” See full CDC report.

Up until the recent study cited above, even though BLV was found in dairy milk, BLV was considered harmless to humans. As a result, the cattle and dairy industry have not been concerned enough to limit our exposure to it.

The study, which was recently done on biopsies of breast tissue from 239 women, revealed startling results. The tissues were tested for the DNA of bovine (cow) leukemia (BLV DNA). Of the 239 tissue samples, it was discovered that in biopsies from cancer free tissue, BLV was found in 29% of the samples, and in tissue with diagnosed breast cancer the incidence of the presence of BLV was 59%!

Also, UC Berkeley researchers published a recent report that supports the findings and states that “the odds of having breast cancer if BLV were present was 3.1 times greater than if BLV was absent.” We found this to be alarming news and will be paying very close attention to the developing story.

The conclusion of the study was that BLV DNA is significantly associated with breast cancer. It’s still not clear whether or not BLV DNA actually causes normal breast cells to become malignant or whether the presence of the virus is a contributing factor to a woman with other risk factors. Further studies need to be done to determine that, but we do know it’s a significant issue and we can surely benefit from the information we do have.

At this time, dairy cows and beef cattle are tested for BLV DNA, but according toVeterinary Services — Centers for Epidemiology and Animal Health, the virus is readily transmitted cow-to-cow and there is no cost effective way to cure it. Furthermore, according to the CDC, it appears that BLV DNA is easily transmitted–not just between cows, but also to other animals including chickens, pigs, and sheep. The full implications of the presence of BLV DNA in most all of the animal protein we eat is not yet clear–but it could be more prevalent than most people would be comfortable with.

Until the cattle and dairy industry accepts that BLV DNA is indeed passing to humans, and it is causing or contributing to the development of breast cancer, we may not get much relief from the industry.

At this point it’s not exactly clear to us how the BLV virus is getting into humans. Those of us who are not willing to wait for the industry to come around with solutions will likely take this new information to mind when making food choices. It may prove to be difficult to limit our exposure to the virus; however, here’s some changes we can make individually to reduce the perceived risks:

Avoid Undercooked Meats

We don’t yet know if this virus is passed through to the meat itself, and we don’t know if it’s passed to us from other animals as well, but we do know that viruses are generally killed by sufficient heat (cooking), so cooking beef and other animal protein thoroughly, in any form, may be a prudent decision.

Avoid Ground Beef

Consumer Reports recently tested 458 pounds of ground beef from dozens of different grocery stores looking for various strains of dangerous bacteria. The results were extremely disconcerting. All 458 pounds of beef they examined contained levels of bacteria that included fecal contamination which can cause blood or urinary tract infections in humans. Some of these toxins cannot be destroyed—even at higher temperatures through proper cooking. We do not know if the BLV virus could be prevalent in ground beef, it stands to reason that it could be one of the most common and dangerous sources distributing the virus. Read the full story here: Ground Beef Warning (confirmed)

Avoid Unpasteurized Dairy

We can limit our dairy consumption to pasteurized products like milk, butter and cheese. Until we have evidence that farmers (even organic farmers) are testing and eliminating BLV from their herds, we will remain concerned and looking deeper into the safest options.

Build a Strong Immune System

Remember, we’re subjected to viruses daily and the #1 best thing we can do to protect ourselves and our families is to get enough sleep, sunshine, exercise, address nutrient deficiencies and do what you can do to stay healthy.

Still, this is such new information; many questions remain unanswered. This is hard news to share and hard news to hear–but, it is important news nonetheless.

Consider this… if these new food choice decisions prevent any of our loved ones from developing breast cancer or other cancers, it is a small price to pay. We’ll continue our research and will be following up on this story regularly.


I take pride in the author, Janet Valenty Former medical technologist with extensive drug testing and clinical chemistry experience. Traded the white coat for a business suit as Director of Marketing of a leading clinical lab with two billion in revenues and left that way back in the 90’s. These days, doing more reading and publishing when not chasing grandchildren.

click on her name to know more.

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