牛類生長激素 BST(Bovine Somatotropin) 對人體有甚麼副作用?(20分)

Some advocacy groups claim not enough research has been done into human health effects in consumers of products from rbST injected cows.[citation needed] However, regulatory, academic and scientific bodies such as the World Health Organization, American Medical Association, the U.S. Food and Drug Administration, the European Commission Directorate for Consumer Health and the American Veterinary Medical Association have all found milk from rbST-supplemented cows to be safe for humans and the same as milk from cows not receiving these supplements.[citation needed] In fact, some claim that there are no ways to differentiate between the milk from herds using BST from those that do not, although other research has shown that rBGH-treated milk is chemically and nutritionally different than milk produced without the artificial hormone.[citation needed]

Several countries, including Canada and most of the European Union, have not approved rbST for use due to trade, economic, political and animal welfare concerns; however, dairy products from rbST-supplemented cows are imported and approved as safe by all countries.

BGH proponents argue that cross-species differences are significant enough to prevent most cross-species effects. (i.e. bST does not "work" in humans.)[9] Monsanto, the largest single producer of rBGH has repeatedly claimed that the amounts are too small and digestion too complete for them to have any direct effect in humans. They claim that there is no scientifically verifiable difference between milk from treated versus untreated cattle.

According to Monsanto and the various government regulatory bodies which have reviewed rbST, milk and meat from cattle supplemented with rbST are safe. Monsanto also states that the only difference between milk from supplemented cattle and unsupplemented cattle is the amount of insulin growth factor 1 (IGF-1) — and that there is not even a difference in the concentration of bST.[10]

Opponents counter that indeed there are differences aside from the higher rate of IGF-1, most importantly that BGH and rBGH (rbST) have a different chain of amino acids. This difference "can markedly change the immunogenic characteristics of a protein".[11] Whether the change in immunogenic characteristics brought about by rBGH actually poses a threat to consumer health has yet to be demonstrated.

Canada's health board, Health Canada, commissioned a study which found "no biologically plausible reason for concern about human safety if rbST were to be approved for sale in Canada. The only exception to this statement is (possible hypersensitivity)."[12]




http://en.wikipedia.org/wiki/Bovine_Somatotropin