In Western diets, dairy and beef are ubiquitous: Milk goes with coffee, melted cheese with pizza, and chili with rice. But what if dairy products and beef contained a new kind of pathogen that could infect you as a child and trigger cancer or multiple sclerosis (MS) 40-70 years later?
However, in two joint statements, the German Federal Institute for Risk Assessment (BfR) and the Max Rubner Institute (MRI) have rejected such theories.
In 2008, Harald zur Hausen, MD, DSc, received the Nobel Prize in Medicine for his discovery that human papillomaviruses cause cervical cancer. His starting point was the observation that sexually abstinent women, such as nuns, rarely develop this cancer. So it was possible to draw the conclusion that pathogens are transmitted during sexual intercourse, explain Dr. zur Hausen and his wife Ethel-Michele de Villiers, PhD, both of DKFZ Heidelberg.
Papillomaviruses, as well as human herpes and Epstein-Barr viruses (EBV), polyomaviruses, and retroviruses, cause cancer in a direct way: by inserting their genes into the DNA of human cells. With a latency of a few years to a few decades, the proteins formed through expression stimulate malignant growth by altering the regulating host gene.
However, viruses – just like bacteria and parasites – can also indirectly trigger cancer. One mechanism for this triggering is the disruption of immune defenses, as shown by the sometimes drastically increased tumor incidence with AIDS or with immunosuppressants after transplants. Chronic inflammation is a second mechanism that generates acid radicals and thereby causes random mutations in replicating cells. Examples include stomach cancer caused by Helicobacter pylori and liver cancer caused by Schistosoma, liver fluke, and hepatitis B and C viruses.
According to Dr. de Villiers and Dr. zur Hausen, there are good reasons to believe that other pathogens could cause chronic inflammation and thereby lead to cancer. Epidemiologic data suggest that dairy and meat products from European cows (Bos taurus) are a potential source. This is because colon cancer and breast cancer commonly occur in places where these foods are heavily consumed (that is, in North America, Argentina, Europe, and Australia). In contrast, the rate is low in India, where cows are revered as holy animals. Also noteworthy is that women with a lactose intolerance rarely develop breast cancer.
In fact, the researchers found single-stranded DNA rings that originated in viruses, which they named bovine meat and milk factors (BMMF), in the intestines of patients with colon cancer. They reported, “This new class of pathogen deserves, in our opinion at least, to become the focus of cancer development and further chronic diseases.” They also detected elevated levels of acid radicals in these areas (that is, oxidative stress), which is typical for chronic inflammation.
The researchers assume that infants, whose immune system is not yet fully matured, ingest the BMMF as soon as they have dairy. Therefore, there is no need for adults to avoid dairy or beef because everyone is infected anyway, said Dr. zur Hausen.