Recombinant Bovine Growth Hormone (rBGH) is a genetically engineered
growth hormone many dairy farmers inject into cows to increase milk
production. There is evidence that rBGH promotes tumor growth
in laboratory animals. Of even greater concern, rBGH significantly
stimulates a cow's production of another hormone that's secreted
in milk, insulin growth factor-1 (IGF-1); when we consume dairy
products that contain IGF-1, we're overdosing ourselves with a hormone
that prompts cells in our bodies to multiply -- including cancer
In May of 1998, Susan Hankinson, Sc.D., published a sobering study
in the medical journal Lancet about the relationship between IGF-I
levels and breast cancer. Thousands of women enrolled in the Harvard
Nurses' Health Study in 1989-90 gave blood samples to be stored.
In 1998, Dr. Hankinsons team identified 397 of these women
who had subsequently developed breast cancer. Tests from the 1989
blood samples showed that those women with high IGF-I levels in
their blood had up to 5 times the risk of developing breast cancer
than those with low IGF-I concentrations.
Subsequent studies have shown that people eating a vegan diet have
lower blood levels of IGF-I. (see related
Moreover, the drug Tomoxifin, routinely given to breast cancer
victims, works by blocking IGF-I production in the body -- the very
thing that dairy and meat consumption increases.
By dramatically increasing the amount of IGF-I in milk, rBGH adds
to the other known health problems with milk.
It is impossible to know whether the milk, ice cream, cheese, butter
or other dairy products you may consume in the US comes from cows
treated with rBGH. This is because Monsanto, the maker of
rBGH, successfully lobbied the government to outlaw labeling which
would draw attention to milk which is rBGH-free.
In fact, recently the Canadian government reviewed the studies
Monsanto used to win FDA approval of rBGH. They found the
studies seriously flawed and lacking, and Canadian government scientists
complained of interference from supervisors who threatened them
unless they gave swift approval of rBGH. (Canada rejected the use of the growth hormone in their cattle.) You can read more
about this story and read the Canadian
government scientists' report.
Being vegetarian is a good step toward protecting yourself against
breast cancer. Choosing rice or soy milks and other substitues to dairy products -- adds greater
protection against several different cancers, particularly breast and prostate cancer.