RACHEL'S ENVIRONMENT & HEALTH WEEKLY #454 .
. ---August 10, 1995--- .
. HEADLINES: .
. MILK SAFETY .
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A scientific and political noose appears to be tightening around
Monsanto corporation's controversial hormone product, rBGH
(recombinant bovine growth hormone), also called rBST (bovine
somatotropin). For the past 18 months, Monsanto has been
aggressively marketing its genetically-engineered hormone to
farmers here and abroad, to increase the milk yield of dairy
cows. Cows injected with rBGH every 2 weeks produce 10% to 20%
more milk than untreated cows. The U.S. Food and Drug
Administration (FDA) in late 1993 declared the milk from
rBGH-treated cows safe. However, new scientific studies
published this summer suggest that milk from rBGH-treated cows
may not be as safe for humans as was previously believed.
Political troubles for rBGH are mounting as well. Because of
unresolved scientific issues related to the safety of milk from
rBGH-treated cows, the international standards-setting
organization in Rome, Italy ---Codex Alimentarius --earlier this
summer rejected a U.S. proposal to declare the use of rBGH safe,
posing no significant health risk. In the debate at the Codex
meeting, the U.S. government promoted rBGH, but the 14-nation
European Union successfully opposed approval, winning by a vote
of 34 to 31. Other European countries besides the EU have
placed a moratorium on use of rBGH, as has Canada. In June,
1995, in Canada the House Committee on Health, an all-party
Parliamentary committee, unanimously called for a minimum 2-year
moratorium on rBGH to examine the unresolved human health issues.
The Agriculture Committee called for a similar moratorium but
not limited to 2 years and limited to human health issues.
Monsanto is aggressively working to have such moratoriums lifted,
but the newly-published scientific information seems certain to
make Monsanto's task increasingly difficult.
Meanwhile back in the U.S., consumer advocacy groups (Food &
Water, Inc., in Marshfield, Vermont [phone: 1-800-EAT-SAFE], and
the Pure Food Campaign in Little Marais, Minnesota [phone:
1-800-451-7670]) are locked in pitched battles with rBGH-using
dairies. Pure Food is using more of a scattergun approach, while
Food & Water has take sharp aim at two major dairy conglomerates
--Land O' Lakes and Cabot Creamery. Both campaigns aim to force
dairies to stop using rBGH. The consumer groups seem likely to
get the upper hand here, as the main arguments being used by the
dairy corporations are undercut by the new scientific findings.
When a cow is injected with rBGH, its milk production is
stimulated, but not directly. The presence of rBGH in the cow's
blood stimulates production of another hormone, called
Insulin-Like Growth Factor 1, or IGF-1 for short. It is IGF-1
that stimulates milk production.
IGF-1 is a naturally-occurring hormone-protein in both cows and
humans. The IGF-1 in cows is chemically identical to the
IGF-1 in humans. The use of rBGH increases the levels of
IGF-1 in the cow's milk, though the amount of the increase is
disputed. Furthermore, IGF-1 in milk is not destroyed by
pasteurization. Because IGF-1 is active in humans --causing
cells to divide --any increase in IGF-1 in milk raises obvious
questions: will it cause inappropriate cell division and growth,
According to the STATISTICAL ABSTRACT OF THE U.S. (1994 edition),
Americans in 1992 each consumed an average of 564.6 pounds of
cows' milk and milk products, or about 1.54 pounds per person per
day; this includes milk, cream, ice cream, ice milk, buttermilk,
cheese, cottage cheese, various "dips," and yogurt. Because milk
is consumed in such large quantities, an increase in a
growth-promoting hormone in milk is of potentially great public
When the National Institutes of Health (NIH) reviewed the safety
of rBGH back in 1991 (concluding that it was safe), they
acknowledged their ignorance about IGF-1: "Whether the additional
amount of insulin-like growth factor 1 in milk from [rBGH-treated
cows] has a local effect on the esophagus, stomach or intestines
is unknown." One of the NIH's 6 recommendations for further
research was, "Determine the acute and chronic actions of IGF-1,
if any, in the upper gastrointestinal tract."
The Council on Scientific Affairs of the American Medical
Association formally expressed concern about IGF-1 related to
rBGH in 1991, saying, "Further studies will be required to
determine whether ingestion of higher than normal concentrations
of bovine insulin-like growth factor [IGF-1] is safe for
children, adolescents, and adults."
The position of Monsanto, and of the dairy conglomerates using
rBGH, are different. Monsanto's public position since 1994 has
been that IGF-1 is not elevated in the milk from rBGH-treated
cows. For example, writing in the British journal, LANCET, in
1994, Monsanto researchers said "...IGF-1 concentration in milk
of rBST-treated cows is unchanged," and "...there is no evidence
that hormonal content of milk from rBST-treated cows is in any
way different from cows not so treated." However, in a
published letter, the British researcher T. B. Mepham reminded
Monsanto that in its 1993 application to the British government
for permission to sell rBGH in England, Monsanto itself reported
that "the IGF-1 level went up substantially [about five times as
much]." The U.S. FDA acknowledges that IGF-1 is elevated in
milk from rBGH-treated cows. Other proponents of rBGH
acknowledge that it at least doubles the amount of IGF-1 hormone
in the milk. The earliest report in the literature found that
IGF-1 was elevated in the milk of rBGH-treated cows by a factor
of 3.6. No one besides Monsanto seems to argue that rBGH
treatment of cows has no effect on IGF-1 levels in their milk.
The dairy conglomerates --Land O' Lakes and Cabot Creamery
--acknowledge that IGF-1 is elevated in their milk. However,
they argue that it doesn't matter. They point out (correctly)
that human saliva has IGF-1 in it, and they argue that that
doesn't matter either because IGF-1 is broken down during
A new study published this month shows this to be wrong. IGF-1
by itself in saliva is destroyed by digestion, but IGF-1 in the
presence of casein (the principal protein in cows' milk) is not
destroyed by the digestive system. Casein has a protective
effect on IGF-1, so IGF-1 in cows milk remains intact in the gut
of humans who drink rBGH-treated milk. There was reason to
believe that this might be true because researchers in 1984 had
shown that another growth hormone, Epidermal Growth Factor (EGF),
in the presence of casein was not degraded by the digestive
system. However, proof had been lacking for IGF-1 until now.
So the saliva argument has been invalidated by scientific
experiment. The question then becomes, what are the likely
effects of IGF-1 in contact with cells of the human
gastrointestinal tract? THIS IS THE QUESTION THE NIH SAID NEEDED
ANSWERING BACK IN 1991. Now there are at least three relevant
1. Some humans suffer from a condition called acromegaly, or
gigantism, which is characterized by excessive growth of the
head, face, hands, and feet. It is caused by excessive natural
production of IGF-1. Importantly, a recent report indicates that
people who suffer from acromegaly have an elevated incidence of
tumors of the colon (a portion of the intestines).
2. Two British researchers, D.N. Challacombe and E.E. Wheeler,
experimented with IGF-1, exposing human cells taken from the
small intestine. They report that IGF-1 induced mitotic activity
--that is to say, IGF-1 promoted cell division. This is an
important finding. Cancer is uncontrolled cell division.
3. As cells divide, at some point they are instructed (by their
genes, in combination with hormone signals) to stop dividing or
they are instructed to die so that the creation of new cells is
matched by the death of cells and no net growth occurs; this is
called "programmed cell death." If "programmed cell death" is
prevented, then cells don't die at the right time, causing an
unnatural increase in cells--another way to make a tumor. A
study published in June by Renato Baserga and others in CANCER
RESEARCH reveals that IGF-1 promotes the growth of cancer tumors
in laboratory animals and in humans by preventing programmed cell
death. This is another important finding.
Taken together, these new studies all point to the need to
understand more about rBGH and its effects on IGF-1 levels in
cows' milk, and an additional need to understand what happens to
the human gastrointestinal tract when it comes in contact with
enhanced levels of IGF-1. The relationship of IGF-1 to cancer
deserves special attention. Even researchers who are known as
proponents of rBGH have recently said in print, "Many more
potential effects of ingested IGF-1 on the gastrointestinal tract
and the local immune system of the gut need to be explored."
In the face of this growing body of scientific evidence, how long
can rBGH-using dairy corporations maintain that their milk,
butter and cheese are wholesome and safe beyond doubt?
 Rodney E. Leonard, "Codex at the Crossroads: Conflict on
Trade, Health," NUTRITION WEEK Vol. 25, No. 26 (July 14, 1995),
pgs. 4-5. NUTRITION WEEK is published by the Community Nutrition
Institute, 910 17th Street, N.W., Suite 413, Washington, DC
20006; phone: (202) 776-0595.
 Reported to us by the Council of Canadians, Ottawa, Canada;
phone (613) 233-2773.
 T.B. Mepham, "Public health implications of bovine
somatotrophin [sic] use in dairying: discussion paper," JOURNAL
OF THE ROYAL SOCIETY OF MEDICINE Vol. 85 (December 1992), pgs.
 Judith C. Juskevich and C. Greg Guyer, "Bovine Growth
Hormone: Human Food Safety Evaluation." SCIENCE Vol. 249 (1990),
 "NIH Technology Assessment Conference Statement on Bovine
Somatotropin," JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Vol.
265, No. 11 (March 20, 1991), pgs. 1423-1425.
 Council on Scientific Affairs, American Medical Association.
"Biotechnology and the American Agricultural Industry." JAMA
[JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION] Vol. 265, No. 11
(March 20, 1991), pg.1433.
 Robert J. Collier and others, "[Untitled Letter to the
Editor]," LANCET Vol. 344 (September 17, 1994), pg. 816.
Monsanto Senior Vice President Virginia V. Weldon, MD, says,
"...the FDA has concluded from detailed studies that IGF-1 is not
increased." See Virginia V. Weldon, "Re 'A Needless New Risk of
Breast Cancer, Commentary, March 20'," LOS ANGELES TIMES April 4,
1994, pg. 6.
 T. B. Mepham and others, "Safety of milk from cows treated
with bovine somatotropin," LANCET Vol. 344 (November 19, 1994),
 William H. Daughaday and David M. Barbano, "Bovine
somatotropin supplementation of dairy cows: is the milk safe?"
JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Vol. 264, No. 8
(August 22, 1990), pgs. 1003-1005.
 C. G. Prosser and others, "Increased secretion of
insulin-like growth factor-1 into milk of cows treated with
recombinantly derived bovine growth hormone," JOURNAL OF DAIRY
SCIENCE Vol. 56 (1989), pgs. 17-26.
 C. Xian, "Degradation of IGF-1 in the Adult Rat
Gastrointestinal Tract is Limited by a Specific Antiserum or the
Dietary Protein Casein," JOURNAL OF ENDOCRINOLOGY Vol. 146, No. 2
(August 1, 1995), pg. 215.
 W. Thornburg and others, "Gastrointestinal absorption of
epidermal growth factor in suckling rats," AMERICAN JOURNAL OF
PHYSIOLOGY Vol. 246 (1984), pgs. G80-G85.
 J. Tremble and A.M. McGregor, "[article title unknown]," in
J.A.H. Wass, editor, TREATING ACROMEGALY (London: International
Society of Endocrinology, 1994), pgs. 5-12. We have not seen
this study; it is cited in an unpublished paper by T.B. Mepham
and P.N. Schonfield, "Health Aspects of BST Milk," prepared for
the International Dairy Federation Nutrition Week conference in
Paris, France, June, 1995. Mepham and Schonfield say this study
reports a "marked tumour excess being evident in the colon" among
 D.N. Challacombe and E.E. Wheeler, "Safety of milk from cows
treated with bovine somatotropin," LANCET Vol. 344 (Sept. 17,
1994), pg. 815.
 Mariana Resnicoff,... and Renato Baserga, "The Insulin-like
Growth Factor I Receptor Protects Tumor Cells From Apoptosis IN
VIVO," CANCER RESEARCH Vol. 55 (June 1, 1995), pgs. 2463-2469.
 Jeanne L. Burton and others, "A review of bovine growth
hormone," CANADIAN JOURNAL OF ANIMAL SCIENCE Vol. 74 (1994), pgs.
Descriptor terms: milk; food safety; insulin-like growth factor
1; food & water; pure food campaign; monsanto; rbgh; bovine
growth hormone; cancer; cell proliferation; studies; apoptosis;
programmed cell death; tumors; rbst; canada; moratoriums; codex
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