Is milk from BST-treated cows safe for human consumption?

Yes.

• Bovine somatotropin, whether recombinant or natural, has no biological effect on humans. This was shown in early trials of therapy for growth hormone deficiency in children. Bovine growth hormone, when injected in large quantities, had no effect. Only human growth hormone was effective in growing children.
• Bovine somatotropin already exists naturally in milk. rBST is chemically identical to naturally-produced BST. About 90% of BST in milk is destroyed by pasteurization, and it is also denatured when milk is cooked or processed for baby formula.
• Bovine somatotropin is broken down, like all proteins that are ingested, into common amino acids. Any trace amounts of undigested BST are biologically inactive since it is species-specific.
• The U.S. Food and Drug Administration (FDA), the National Institutes of Health (NIH), the American Medical Association's Council on Scientific Affairs, the World Health Organization, and the American Dietetic Association, all have concluded after studying the evidence that milk from BST-treated cows poses no health risk to humans.
• See:

  Juskevitch CJ, Guyer CG. Bovine growth hormone: human food safety evaluation. Science 1990;249(4971):872-873.

  Grossman CJ. Genetic engineering and the use of bovine somatotropin. JAMA 1990;264(8):1028.

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Prepared Summer 1997 by Bernadene Magnuson, Ph.D.
University of Idaho, Dept. of Food Science and Toxicology - EXTOXNET FAQ Team.