For many years milk marketers have provided consumers with a plethora of choices -- regular, reduced fat, low fat, nonfat, lactose-reduced, etc., etc. All such products have something real to offer. Unfortunately, for the past few years many have decided to add labeling that their milk comes from cows that "were not treated with rBST" (recombinant bovine somatotropin). Implicit in such labeling is the idea that milk from such cows is in some way different, indeed better, than milk from rBST-treated animals -- even though this isn't true. A new study demonstrates clearly, however, that milk is milk -- no matter if the cows are treated with rBST or if they are only exposed to the BST that they make themselves.
In the July 2008 issue of the Journal of the American Dietetics Association (Vol. 108, p. 1198), Dr. J. Vicini and colleagues from Monsanto and the Pennsylvania State University present the results of analyses they performed on conventional milk, organic milk (which by definition may not come from rBST-treated cows), and non-organic milk labeled as coming from cows "not treated with rBST."
The researchers analyzed samples of each type of milk (all were pasteurized) purchased from stores in the forty-eight contiguous United States. In brief, they found that none of the milks contained antibiotic residue and that there were slightly fewer bacteria in the conventional milk than in either of the other two types (the difference was not great enough to have an impact on human health).
All three types had similar levels of BST, and the conventional and "rBST-free" milk had higher levels of insulin-like growth factor (IGF) than the organic milk --but again the differences were so small as to make no practical difference to humans consuming the milk. Indeed, as the authors pointed out, IGF is a protein that would be broken down in the course of digestion by humans and therefore could not affect humans' metabolism. Further, the differences they observed would be only 0.003% of the amount of IGF produced by humans each day.
As far as nutritional quality, there were similar percentages of fat and lactose in all three types of milk, while the organic milk had slightly more protein -- but again the difference was not great enough to have an impact on humans' nutritional requirements.
In summary, the authors found that "[r]esults of this study indicate that there are few and minor differences in the composition of conventional, rBST-free, or organic labeled milk, and all milk is wholesome." If consumers wish to pay a premium for rBST-free labeled milk or organic milk, that of course is their privilege. They should realize, however, that they are not receiving any real benefits for their extra expenditure.