This health education material has been reviewed favorably by the American Academy of Family Physicians Foundation.

What is bST?

bST, or bovine somatotropin, is a natural protein hormone made by cows. Protein hormones are made by the body to help regulate its normal processes. bST helps young cattle grow and adult cows produce more milk. It always has been present in milk at very low levels. bST is not active in humans. In people, it is completely broken down like any other protein.

If cows make bST and it's a natural part of milk, why are we talking about it?

It has been known for a long time that supplementing a cow with small amounts of bST will improve her efficiency in producing milk. Only recently, however, has it been possible to make bST in quantities that can be made available on a wide scale to dairy farmers.

Does bST alter milk's wholesomeness?

Absolutely not. The milk is unchanged and just as nutritious as always -- full of calcium, protein, phosphorus and vitamins.

Does the natural level of bST in milk increase in supplemented cows?

No, the level of bST in milk stays the same. The extra bST is used by the cow.

Is milk from bST-supplemented cows safe for children?

Yes. The milk is the same as it always has been. According to Dr. Norman Kretchmer, a pediatrician at the University of California, milk from cows that have been supplemented with bST is "safe for the human infant and adult and is nutritionally similar to ordinary milk." (Kretchmer N. Pediatrics. 1991:88:1056-7.)

Will the use of bST increase antibiotic residues in milk?

No. Federal and state regulations ensure that the quality of milk is protected within very strict, exact standards. Milk is carefully tested throughout its passage from the farm to the store to guarantee that it is fresh, healthy and safe when it reaches you.

Does giving cows bST increase my risk of allergies?

No. If you or family are not allergic to milk products now, you will not be allergic to milk from bST-supplemented cows.

Is the FDA the only agency that says bST is safe for human consumption?

No. Regulatory and scientific bodies in at least 50 countries, including the United Kingdom, Canada, France and Germany have authorized milk and meat from cows supplemented with bST as safe for people of all ages.

For more information on rbST in other countries, click here

For more information on Posilac and human safety, click here

What do health experts say about bST?

Health experts agree that milk and meat from cows supplemented with bST are as safe as milk and meat from cows that are not supplemented. Here are some of their statements:

The Food and Drug Administration (FDA): "Completed studies have demonstrated that the food from bST-treated cows is safe for human consumption." (FDA Talk Paper August 17, 1992.)

The National Institutes of Health (NIH): "The composition and nutritional values of milk from bST-supplemented cows is essentially the same as milk from untreated cows... (M)eat and milk from rbST-treated cows are as safe as that from untreated cows." (NIH Technology Assessment Conference Statement on Bovine somatotropin. JAMA. 1991:265:1423-1425)

The Journal of the American Medical Association (JAMA): "The FDA has answered all questions and concerns about the safety of milk from bST-supplemented cows..." (JAMA. 1990:264:1003-1005)

Science: "The data evaluated by the FDA documented the safety of food products from animals treated with rbGH." (Bovine Growth Hormone: Human Food Safety Evaluation. Science. 1990:249:875-884.)

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