Bovine Growth Hormone : Part 2

by Food and Drug Administration (FDA)

(Page 2 of 2)

Grounds for Decision

Before FDA allows the full-scale commercial marketing of bST or any new animal drug the manufacturer must provide sound scientific data showing that its bST product is effective for the proposed use (increasing milk production) and causes no safety concerns for human or animal health. The sponsor must also provide adequate data on the environmental impact of the drug's use. However, in the meantime, FDA has allowed the marketing of meat and milk from bST-supplemented cows in experimental herds because it has determined that these foods meet the requirement of federal law. Federal law permits the commercial sale of food products from animals in investigational studies only when the sponsor has demonstrated that they present no public health risk. Some of the main scientific grounds for FDA's decision are:

Bovine somatotropin is a protein hormone, and this means that when a product containing bST is eaten, it breaks down during digestion in the gastrointestinal tract into inactive fragments without any effect on the person (or cow) who ate it. That is why cows must be injected with bST for it to be effective.

Experiments with rats have shown that they are unaffected by oral administration of bST. Rats are an appropriate model because bST is biologically active in rats when injected. Thus, any bST escaping digestion in the rat would have biological effects, such as effects on growth.

Studies indicate that bST is not effective in humans and other primates even if injected. In the 1950s, physicians tried to treat human dwarfism in children by injecting them with bovine somatotropin, but it had no effect because the amino acid structure of human somatotropin is 35 percent different than bST.

BST is a natural constituent of milk. It is produced by the pituitary gland and has always been present in the meat and milk of cows. The bST injected to increase milk production merely increases the amount to which the cow is exposed.

Supplementation with bST does not significantly affect the nutritional qualities of milk or interfere with milk processing. Subtle changes, primarily in the milk fat, occur in the first few weeks of bST supplementation due to metabolic adjustments in the cow. However, this is temporary, and because it occurs to some degree during early lactation in untreated cows the milk contains milk fat well within the normal composition range. Other studies have shown that bST has minimal, if any, effect on the remaining components and characteristics of milk, including protein, minerals, protein coagulation, cholesterol, starter cultures, and flavor. In fact, FDA scientists are not aware of any technology that can detect a difference between milk and dairy products from bST-supplemented cows and similar products from untreated cows.

Other Considerations

There is, however, at least one area of controversy concerning bST that, under the law, FDA may not consider in making its approval decision: the potential social and economic impact of the growth hormone on the nation's dairy farmers. According to the drug's opponents, the lower prices of a more plentiful milk supply will adversely affect thousands of small dairy farms in an already precarious economic situation.

Fear for the continued existence of family farms has fueled the opposition to the growth hormone in the dairy states and increased support for activist Rifkin's anti-bST campaign. Rifkin was back in Washington this past January once again to claim that bST is, among other things, bad for farmers, cows and taxpayers. In support of family farms, Ben & Jerry's Homemade, which buys milk from small Vermont producers, last August placed on its ice cream containers a sign opposing the hormone and calling for the preservation of small farms. Since then, the firm has received more than 1,000 requests for more information on the issue.

On the other hand, many bST supporters realize that dairy farming has changed a great deal since the 1950s largely as a result of technological innovation and believe that further changes in the industry are inevitable due to emerging technologies.

It does appear that even after FDA answers all scientific questions about bST and reaches a decision about its approval for general use in the nation's dairy cattle, it may continue to be a controversial topic. However, one thing is certain. Bovine somatotropin will not be approved for commercial use unless, and until, FDA is completely satisfied that scientific data show that it meets all safety and efficacy requirements for commercial marketing.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.