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#454 - Milk Safety, 09-Aug-1995

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.[1] 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.[2] 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.
[3] The IGF-1 in cows is chemically identical to the IGF-1 in humans.
[4] 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, causing tumors?

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 health interest.

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."[5]

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."[6]

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."[7] 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]."[8] The U.S. FDA acknowledges that IGF-1 is elevated in milk
from rBGH-treated cows.[4] Other proponents of rBGH acknowledge that it
at least doubles the amount of IGF-1 hormone in the milk.[9] 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.[10] 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 digestion.

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.[11] 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.[12] 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 studies.

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).[13]

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.[14] 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.[15] 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."[16]

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?

--Peter Montague

=====

[1] 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.

[2] Reported to us by the Council of Canadians, Ottawa, Canada; phone
(613) 233-2773.

[3] 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. 736-739.

[4] Judith C. Juskevich and C. Greg Guyer, "Bovine Growth Hormone:
Human Food Safety Evaluation." SCIENCE Vol. 249 (1990), pgs. 875-884.

[5] "NIH Technology Assessment Conference Statement on Bovine
Somatotropin," JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Vol. 265,
No. 11 (March 20, 1991), pgs. 1423-1425.

[6] 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.

[7] 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.

[8] T. B. Mepham and others, "Safety of milk from cows treated with
bovine somatotropin," LANCET Vol. 344 (November 19, 1994), pgs. 1445-
1446.

[9] 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.

[10] 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.

[11] 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.

[12] W. Thornburg and others, "Gastrointestinal absorption of epidermal
growth factor in suckling rats," AMERICAN JOURNAL OF PHYSIOLOGY Vol.
246 (1984), pgs. G80-G85.

[13] 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 acromegalics.

[14] D.N. Challacombe and E.E. Wheeler, "Safety of milk from cows
treated with bovine somatotropin," LANCET Vol. 344 (Sept. 17, 1994),
pg. 815.

[15] 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.

[16] Jeanne L. Burton and others, "A review of bovine growth hormone,"
CANADIAN JOURNAL OF ANIMAL SCIENCE Vol. 74 (1994), pgs. 167-201.

Descriptor terms: milk; food safety; igf-1; food & water; pure food
campaign; monsanto; bgh; cancer; cell proliferation; studies;
apoptosis; programmed cell death; canada; moratoriums; codex
alimentarius; acromegaly;