BOVINE GROWTH HORMONE:  HARMLESS FOR HUMANS
by Beverly Corey 

Generations of Americans have been told that Milk is nature's most perfect
food, and the nutritional value of milk supports this claim.  Milk sustains 
infants and is also beneficial to adults, including the elderly. Many people
begin the day with it by the glass, in cereal, coffee, and in baby's
bottle.  And because it is perceived as perfect and essential, some 
consumers and processors of milk products are highly uneasy about the 
decision of the Food and Drug Administration to allow marketing of milk from
experimental herds injected with bovine growth hormone, also known as bovine
somatotropin, or bST. 

Some consumers suspect that this hormone, even if not harmful, at least 
detracts from the purity of milk. Such skepticism has many sources, ranging 
from a desire to protect children and an uneasiness about nature-altering 
biotechnology, to the underlying apprehension that life-sustaining gifts of 
agriculture are becoming polluted by chemistry. (See Perspective on Food
Biotechnology in the March 1990 FDA Consumer.)

Writing not long ago about chemical firms that want to market bST, Milwaukee
Journal columnist Joel McNally captured the public's wary state of mind:
Consumers, he wrote, might have second thoughts about . . . milk enhanced by
the same companies that gave us such taste treats as vinyl chloride and 
polystyrene.

Adverse publicity has made bST a hot political issue among dairy farmers, 
particularly in Wisconsin, Minnesota and Vermont, many of whom demand that
the hormone be banned. At a meeting in Washington, D.C., last summer, Jeremy
Rifkin, president of the Foundation on Economic Trends and a frequent critic
of biotechnology, launched a campaign (the second in three years) against 
bST as a potentially dangerous drug with no redeeming social value.  He was 
joined by consumer, animal welfare, and environmental groups, as well as 40 
public officials.  The grass-roots pressure resulted in a partial boycott of
milk produced by experimental herds that receive injections of the growth 
hormone in clinical animal studies being performed by commercial sponsors of
the drug. 

Subsequently, the supermarket chains of Safeway, Kroger, Stop & Shop, and 
Vons last August said they had agreed to not market milk from the 
bST-supplemented cows, and Kraft USA, Borden's, and Ben & Jerry's Homemade
(the Vermont ice cream maker) announced they would not use it in their
products. The country's largest dairy cooperative, Associated Milk Producers
Incorporated, issued a statement that its 21,000 members will not give the
hormone to their cows.

People are nervous about this substance, says Alan Parker, the Ben & Jerry
spokesman.  Coming on the heels of the widely publicized concerns about Alar
the growth regulator for apples whose cancer-causing metabolites resulted in
the manufacturer withdrawing it from the market the experiments with bST, in
Parker's view, made many consumers feel that they're losing contact with
their food. 

                               Unfounded Fears

BST is biologically inactive in humans. FDA concluded almost five years ago,
based on extensive scientific investigation, that milk and meat from
bST-supplemented experimental dairy cows may be used for human consumption
without causing a risk to the public health.  Fears about the growth
hormone's effect on human health do not withstand close scrutiny. 
Furthermore, talk about natural milk in the American marketplace is a piece 
of nostalgic fiction. Gone are the days when one consumed milk in the 
natural state in which it was drawn from the udder.  Milk that is 
pasteurized to destroy bacteria, homogenized to evenly distribute fat, and
fortified with vitamin D to improve nutritional qualities is the result of
technological advances. Skim and low-fat milk are supermarket best sellers. 
Even the recent introduction of unrefrigerated ultra-long-life milk, yet
another type of processed milk, represents the application of current 
technology to milk, and it has met little consumer resistance.

Some scientists believe that bST will ultimately benefit the dairy industry 
as have the application of other technologies by increasing the efficiency
of milk production and controlling the retail prices of milk and dairy
products to consumers.

BST is a natural product of the pituitary gland of cattle. It stimulates
growth in immature cattle and, as a Russian scientist first noted in 1937,
it increases milk yield in lactating cows.  Research on the substance until 
the early 80s was stymied by shortages of bST, which could only be extracted
from slaughtered animals and varied in purity. In recent years, however,
newly perfected genetic engineering techniques have enabled scientists to 
produce the hormone in sufficient quantity and quality for intensive study. 
The early findings that bST increases milk production 10 to 25 percent gave 
the hormone such economic potential that four firms Monsanto, American
Cyanamid, Upjohn, and Elanco applied to FDA for marketing approval for their
brands of genetically produced bST. 

                            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. 

Beverly Corey is a member of FDA's speechwriting staff.