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FDA allows Genetically-Modified rBGH to Endanger Milk

Growth Hormones Would Endanger Milk
Los Angeles Times, July 27, 1989
FDA Ignores Evidence on Cancer Risks

With the Food and Drug Administration ready to approve the use of genetically engineered growth hormones in cows to boost milk production, concerns are mounting among dairy farmers, state legislatures, animal-rights activists and consumer and public-interest groups.

These hormones, known as rBGH, are manufactured by chemical companies - Monsanto, American Cyanamid, Upjohn and Eli Lilly together with Dow - who anticipate $500-million annual worldwide sales.

Their promotional hype claims that the hormones are natural," that they are not found in milk, that they increase milk yields up to 25%, that they do not harm cows, that they do not alter milk quality and that they are safe for humans. The FDA also agrees that bovine growth hormones are safe and have allowed the sale of unlabeled milk and meat from rBGH cows for about five years. These claims, which are based on industry-contracted research at more than 20 U.S. university dairy science departments, are misleading in the extreme.

Apart from the national surplus of milk and anticipated foreclosure of thousands of small dairy farms if milk production is increased and milk prices reduced, the effectiveness of bovine growth hormones is exaggerated. Furthermore, the nutritional quality of milk and cheese is altered; fat is increased and casein decreased. Stress effects have been noted in cows hyper-stimulated by rBGH. These include increased susceptibility to infection, infertility, loss of fat, heat intolerance and "burnout" or lactational failure; severe stress diseases including gastric ulcers, arthritis and kidney and heart abnormalities have also been induced in pigs. Additionally, bovine growth hormones are likely to be misused as a growth promoter in calves, pigs and sheep, particularly as there are no practical methods for detecting the hormone in meat, and in view of the abusive track record of the meat industry regarding hormonal and other feed additives.

Apart from economic and veterinary concerns, bovine growth hormones pose grave consumer health risks that have not been investigated by the industry or FDA.

-Bovine growth hormones are not "natural." The FDA now admits that they are up to "3% different in molecular structure" from the normal hormone. Increased rBGH levels in milk and blood have been found in injected cows. rBGH and its digested products could be absorbed from milk into blood, particularly in infants, and produce hormonal and allergic effects.

-Increased levels of cell-stimulating growth factors, apparently identical to those in humans, have been reported in rBGH milk. These could induce premature growth and breast stimulation in infants, and possibly promote breast cancer in adults.

-Increased bacterial infections in rBGH cows will require treatment with antibiotics that will pass into milk. This is likely to result in antibiotic-resistant infections in the general population. Also, the stress effects of bovine growth hormones in cows could suppress immunity and activate latent viruses, such as bovine leukemia (Leukosis) and bovine immunodeficiency viruses, which are related to the AIDS complex and may be infectious to humans.

-Steroids and adrenaline-type stressor chemicals induced in cows by these hormones are likely to contaminate milk and may be harmful, particularly to infants and young children.

-The fat and milk of cows are already contaminated with a wide range of carcinogenic contaminants, including dioxins and pesticides. Bovine growth hormones reduce body fat and are likely to mobilize these carcinogens into milk, with cancer risks to consumers.

What is to be done? State legislatures should be pressured to ban rBGH. The FDA should be petitioned to ban the manufacture, domestic sale and export of the hormones until all safety questions can be resolved. Congressional oversight should focus on industry's misleading and self-interested claims on rBGH, and the FDA's regulatory abdication. Finally, consumers should recognize these hormones as industry's latest unsafe contribution to the brave new world of chemicalized food and mechanized farming.

Statement by the Cancer Prevention Coalition on IGF-1 and Breast and Colon Cancer
January 23, 1996

The FDA has ignored the wide range of converging evidence that associates increased consumption of insulin growth factor-1 (IGF- 1), which increases in milk from rBGH treated cows, with a potential risk of breast and other types of cancer.

Published research shows that rBGH use on dairy cows induces a marked and sustained increase in levels of insulin-like growth factor-1, or IGF-1, in cow’s milk. This is admitted by FDA (Juskevich & Guyer, 1990), and more explicitly by others (Prosser 1988; Prosser 1989; Mepham, 1992). A recent admission by another manufacturer of rBGH (Eli Lilly & Co.) reports a ten fold increase in IGF-1 levels. Furthermore, there is suggestive evidence that IGF- 1 in rBGH milk is more bioactive than in non-hormonal milk (Mepham, 1992).

IGF-1 regulates cell growth, division and differentiation, particularly in children. Human and normal bovine IGF-1 are identical, they are largely bound in protein and thus probably less biologically active than unbound IGF1 in rBGH derived milk.

IGF-1 is not destroyed by pasteurization. In fact this process substantially increases IGF-1 levels in milk. (Juskevich and Guyer, 1990). Nor is IGF-1 destroyed by digestion. Moreover, FDA admits that IGF-1 is readily absorbed across the intestinal wall (Juskevich & Guyer, 1990); this was also previously admitted by Monsanto in 1987. Further confirmation is also provided by other authorities (e.g. Mepham, 1992). Additionally, recent research indicates that IGF-1 can be absorbed into the bloodstream where it can effect other hormones. (Donovan and Odle, 1994)

FDA and other industry sources have not published any detailed studies on the oral toxicity of IGF-1 Rather, they have consistently refused to make available their findings and raw data. A highly condensed summary of an IGF- 1 Monsanto short term test in mature rats was released by FDA (Juskevich & Guyer, 1990). The agency alleges that this study confirms IGF- 1's "lack of oral activity." At the outset it should be noted that the Monsanto test was contracted out to Hazelton Laboratories, which has a two decade history of misrepresentation of scientific data. (Epstein, 1978). However, even the cited Monsanto/Hazelton data explicitly reveal statistically significant evidence of growth promoting effects. Feeding relatively low doses of IGF-1 to mature rats for only two weeks resulted in statistically significant and biologically highly significant systemic effects: increased body weight; increased liver weight; increased bone length; and decreased epiphyseal width. These results are confirmatory of prior theoretical predictions.

The FDA has completely failed to investigate the effects of long-term feeding of IGF- 1 and treated milk on growth, or on more sensitive sub-cellular effects, in infant rats or infants of any other species.

Significantly, cows injected with rBGH show heavy localization of IGF-l in breast (udder) epithelial cells; this does not occur in untreated cows. (Furlanetto, et al, 1984; Gregor, et al, 1985; Campbell, et al, 1986.) IGF-1 induces rapid division and multiplication of normal human breast epithelial cells in tissue cultures. It is highly likely that IGF- 1 promotes transformation of normal breast epithelium to breast cancers. (Furlanetto, et al, 1984; Harris, et al, 1992, growth factors such as IGF-1 "are responsible at least in part for the evolution of normal breast epithelia to breast cancer...'). Moreover, IGF-1 maintains the malignancy of human breast cancer cells, including their invasiveness and ability to spread to distant organs. (Lippman, 1991, 1993). IGF-l has been similarly associated with colon cancer (Tricolo, et al, 1986).

The undifferentiated pre-natal and infant breast is particularly susceptible to hormonal influences. (Ekbom, et al. 1992) Such imprinting by IGF-1 may increase future breast cancer risks, and may also increase the sensitivity of the breast to subsequent unrelated risks such as mammography and the carcinogenic and estrogen-like effects of pesticide residues in food, particularly in pre-menopausal women. (Elwood, et al, 1993).

Concerns about increased levels of IGF- 1 in milk from cows treated with rBGH are not new. In 1990, the National Institutes of Health (NIH) Consensus panel on rBGH expressed concerns on adverse health effects of IGF-1 in rBGH milk, calling for further study on the treated milk's impacts, especially on infants. (NIH, 1991). In a 1989 letter to the FDA, I warned that the effects of IGF-1 "could include premature growth stimulation in infants, [breast enlargement] in young children and breast cancer in adult females." More recently, the Council on Scientific Affairs of the American Medical Association stated: "Further studies will be required to determine whether the ingestion of higher than normal concentrations of bovine insulin-like growth factor is safe for children, adolescents and adults." (AMA, 1991). Instead of further study, the FDA allowed for uncontrolled, unlabeled sales of treated milk to unwitting consumers.

Given the potential health impacts of consumption of milk and other dairy products derived from rBGH treated cows, all such products at a minimum be labeled so that consumers are aware of what they are purchasing and consuming. More prudently the FDA approval of rBGH should be withdrawn until the agency performs adequate long term testing on the impacts of increased levels of IGF- 1 in milk and other dairy products derived from rBGH treated cows.


American Medical Association, Council on Scientific Affairs. Biotechnology and the American Agriculture Industry. JAMA 1991:265:1429-1436

Ayre, S.G. et al. Neoadjuvant low-dose chemotherapy with insulin in breast carcinomas. Eur. J. Cancer. 1990:26:1262-1263

Campbell, P.G. and Baumrucker, C.R. Characterization of insulin-like growth factor-1/somatomedin-C receptors in bovine mammary gland. Endocrinol. 116 (Suppl. 1 Abstract: 223, 1985.

Donovan, S.M. and Odle J., 1994. Growth Factors in Milk as mediators of Infant development. Annual Review of infant development. Annual Review of Nutrion, 14:147-67.

Ekbom, A. et al. Evidence of prenatal influence on breast cancer risk. The Lancet Oct.24, 1992:1015-1018.

Epstein, S.S. Polluted Data, The Sciences, Vol.18, 16-21, July, August, 1978.

Epstein, S.S. Potential public health hazards of biosynthetic milk hormones. Int.J. Health Services 1990:20:73-84.

Furlaneto, R.W., DiCarlo, J.N. Somatomedin-C receptors and growth effects in human breast cells maintained in long-term tissue culture. Cancer Res. 1984:44:2122-2128.

Glimm, D .R. et al. Effect of bovine somatropin on the distribution of immunoreactive insulin like growth factor-i in lactating bovine mammary tissue. J. Dairy Sci. 1988:71:2923-2935.

Gregor, P. and Burleigh, B.D. Presence of high affinity somatomedin/insulin-line growth factor receptors in porcine mammar~ gland. Endocrinol. 116 (suppl. 1, Abstract) :223, 1985.

Hanson, M.K. Biotechnology & milk: benefit or threat? Consumer Policy institute, New York. 1990.

Harris, J.R. et al. Breast Cancer. NEJM 1992:7;473-480

Juskevich, J.C., Guyer, C.G. (FDA). Bovine growth hormone food safety evaluation. Science 1990:249:875-884.

Lippman, M.E. The development of biological therapies for breast cancer. Science 1993:259:631-632.

Marx, J. Oncogenes evoke new cancer therapies. Science 193:249:1376-1378.

McBride, B.W. et al. The influence of bovine growth hormone on lactation of dairy cows. Res. Dev. Agric. 1988:5:1-21

Mepham, T.B. Public health implications of Bovine somatotropin use in dairying: discussion paper. J. Royal Soc. Medicine 1992:85:736-739

National Institutes of Health, Technology Assesment Conference Statement on bovine Somatotropin. JAMA 191:265:1423-1425

Prosser, C.G. Bovine somatotropin and milk composition. The Lancet November 19, 1988:1201

Prosser, C. G. et. al. Increased secretion of insulin-like growth factor 1 into milk of cows treated with recombinantly derived bovine growth hormone, J. Dairy Res. 1989:56:17-26

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