Science in Society Archive

Letter to the New Zealand Minister of Food and Fibre

The Honourable John Luxton
Minister of Food and Fibre
Parliament Buildings
Wellington
New Zealand

Dr Mae-wan Ho
England 18th May 1999

Your Excellency

I have recently learned that the New Zealand government is considering registering genetically engineered bovine growth hormone (rBGH or BST) for use in your diary industry.

I am writing to you as a scientist to urge you to consider the precautionary principle very carefully before making any decision. The precautionary principle clearly states that lack of full scientific certainty should not be used as a reason for postponing measures to avoid or minimize a threat.

Lack of Full Scientific Certainty Regarding BST

· As part of their 55,000 page application to the FDA in 1985, Monsanto was required to submit a chart identifying every amino acid on the 191 amino acid chain structure of BST. On that chart, amino acid 144 was represented as being lysine. However, a Monsanto scientist, Bernard Violand later published evidence (Violand, B.N. et al (1994) Journal of Protein Science. 3 (7) 1089-1097) that a mistake had resulted in the production of BST and that instead of lysine at position 144, an aberrent amino acid, epsilon-N-acetyllysine was being transcribed. One amino acid difference in the middle of a chain can have serious consequences. Monsanto has never officially admitted this error and the FDA was unaware of it whilst the drug was under review.

· In the FDA paper (page 878, reference 47) Jerome Moore was cited (Moore J.A. et al (1988) Endocrinology, 122, 2920) by writing 'The need to pursue more definitive studies has already been stated as unnecessary because it has been determined that at least 90 percent of (BST) is distroyed upon pasturization of milk.' The FDA reviewers have mis-cited Moore, he never researched pasteurization, his expertise is in the feild of human growth hormone. They also cited Paul Groenewegen to subtantiate that conclusion. However, Groenewegen pasteurised milk at 162 degrees fahrenheit for 30 mins, when 15 seconds was called for, and only destroyed 19% of the BST. Again, a mis-quote from the scientific literature by the FDA reviews.

· Had the FDA known about these mistakes they would have certainly invalidated Monsanto's $ 500 million worth of research and not granted the licence application until further testing had been done. Monsanto may have eliminated the abberent amino acid on their own but it is not known whether this has been done nor whether their currently marketed product POSILAC is an exact duplicate of naturally occuring BGH or not . It has never been tested nor genuinely regulated by the U.S. FDA.

Milk and the Cancer Connection

·In 1995 researchers at the National Institutes of Health reported that IGF-1 plays a central role in the progression of many childhood cancers and in the growth of tumours in breast cancer, small cell lung cancer, melanoma and cancers of the pancreas and prostate ( LeRoith, Derek, et al. The role of insulin-like growth factor 1 receptor in cancer. Annals New York Academy of Sciences, Vol. 766, Sept 7, 1995. pp 420-08). On January 23rd, 1998 researchers at the Harvard Medical School released a major study providing conclusive evidence that IGF-1 is a potent risk factor for prostate cancer (Chan, June M et al. Plasma insulin-like growth factor 1 and prostate cancer risk: a prospective study. Science, Vol. 279, Jan 23, 1998, pp 563-66). Other research provides more evidence of IGF-1's link to breast and colon cancer and a strong link between cancer risk and a high level of IGF-1 is now indisputable.

· All mammals produce IGF-1 molecules of similar structure and human and bovine IGF-1 are completely identical. The question is why do some people have high levels of IGF-1 while others do not? Is it all genetically ordained or could there be other outside factors influencing IGF-1 levels? In 1996 Dr. Samuel Epstein of the University of Illinois clearly warned of the danger of high levels of IGF-1 contained in milk from cows injected with synthetic bovine growth hormone (Epstein, Samuel S. Unlabeled milk from cows treated with biosynthetic growth hormones: a case of regulatory abdication. Internation Journal of Health Services, Vol 26, No1, 1996, pp 173-85).

· There is now genuine concern within the scientific community about the safety of milk from BST - treated cows. Concerns that began as early as 1988 in both England and the U.S. The main concern is the level of IGF-1 found in milk from treated cows; estimates vary from twice as high to 10 times higher than in normal cow's milk (Mepham, T.B. et al. Safety of milk from cows treated with bovine somatotrophin. The Lancet, Vol. 344, July 16, 1994, pp 197-98). There is also concern that the IGF-1 found in treated milk is much more potent that that found in regular milk because it seems to be bound less firmly to its accompanying proteins (see Epstein, Samuel, S.).

· Researchers at the FDA reported in 1990 that IGF-1 is not destroyed by pasteurization and that pasteurization actually increases it concentration in BST-milk. They also confirmed that undigested protein could indeed cross the intestinal wall and cited tests which showed that oral ingestion of IGF-1 produced a significant increase in the growth of a group of male rats. It is not known whether IGF-1 in milk consumed by humans is digested and broken down into its constitutive amino acids, as no human studies have ever been conducted. Research done on a similar hormone, Epidermal Growth Factor, has shown that this hormone is protected against digestion in the human gut, when ingested in the presence of casein which is a main component of milk (Playford, R.J., et al. Effects of luminal grwoth factor preservation on intestinal growth. The Lancet, Vol. 431, April 3 1993, pp 843-48).

· Thus there is a distinct possibility that IGF-1 in milk could also avoid digestion and make its way into the intestine where it could promote colon cancer. It is also conceivable that it could cross the intestinal wall in sufficient amounts to increase the blood level of IGF-1 significantly and thereby increase the risk of breast and prostate cancers.

There are too many serious questions surrounding the use of milk from BST treated cows to allow its continued sale. In Europe we have maintained a moratorium on the use of BST and products from BST-treated cows are not sold in countries within the union. BST in banned in Austrilia and Japan and Canada is also resisting pressure from the U.S. and the biotechnology lobby to approve the use of BST commercially.

In light of the serious concerns about the safety of human consumption of milk from BST-treated cows, I strongly suggest you exercise vigilance and resist pressure to approve BST in New Zealand, so as to protect yourselfves and others in the global market place against the very real cancer risks posed by IGF-1.

Yours Faithfully

Dr Mae-Wan Ho
Open University

Article first published 27/07/00



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