Research on health
Consumer groups, health organizations, private physicians, nutritionists and scientists from around the world have expressed serious concerns about health risks to cows and humans from rBGH.
Cows injected repeatedly with rBGH become unnaturally stressed. Monsanto's own confidential files (original creator of rBGH), submitted to the FDA in 1987 and anonymously leaked, revealed widespread pathological lesions, infertility and higher rates of mastitis (udder infections) in treated cows.
rBGH also has been shown to increase birth disorders, hoof problems causing an animal to go lame, heat stress, diarrhea and other gastrointestinal disruption, and is associated with higher levels of pus in the milk.
The antibiotics used to treat, for instance, mastitis — such as penicillin, amoxicillin and erythromycin — also are used to treat infections in humans. Some bacteria resistant to these antibiotics can pass into humans through dairy consumption, increasing antibiotic resistance in humans, a serious problem today.
It's known that rBGH also increases the level of another powerful growth hormone, IGF-1, which regulates cell growth and division. IGF-1 occurs naturally in cows and humans to some degree.
But hundreds of studies have associated excess levels of IGF-1 with increases in breast, prostate, colon and lung cancers in people. For instance, a report by the Nurses Health Study at Harvard Medical School concluded that consumption of rBGH milk could influence cancer risk by a mechanism involving IGF-1.
The World Health Organization never has declared rBGH safe. The United Nation's main food safety body, Codex Alimentarius, has considered rBGH twice — in 1997 and 1999 — and both times concluded there was no consensus that rBGH was safe for human consumption.
The American Medical Association issued an opinion in 1990 that rBGH was safe, based mostly on evidence supplied by the FDA. But a year later, the AMA's Council on Scientific Affairs said, "Further studies will be required to determine whether ingestion of higher than normal concentrations of bovine IGF-1 is safe for children, adolescents and adults."