by Amanda Smith, Associate Editor
Two decades have passed since the FDA approved rBST (BST), and it continues to be one of the most highly scrutinized products on the market. Extensive human health evaluations were conducted prior to its approval, which led to the conclusion that it does not present a human health hazard.
Yet, in 2013, the European Union's Joint Committee on Food Additives posed four new questions as it reevaluated the protein's impact on human health. At the Cornell Nutrition Conference, Bob Collier, with the University of Arizona, highlighted the answers to the groups.
1. Is there a possible increase in antibiotic residues in milk due to the treatment of mastitis?
Over the past decade, there has been a steady reduction in bulk milk tankers testing positive for antibiotic residues. Furthermore, noted Collier, there is no evidence there has been additional residue contamination with BST use.
Four herd health studies conducted since BST's approval failed to find a significant association between BST use and an elevated mastitis incidence.
2. Is there a possible IGF-1 (insulin-like growth factor) elevation in the milk of BST-supplemented cows?
Cows' somatotropin molecule is not similar to the human molecule; even if BST were administered, it would not cause a response in the human body. There is no evidence, noted Collier, that milk constitutes a human health risk due to IGF-1 or that IGF-1 escapes the digestion process.
There is a large range in bulk milk IGF-1. In the untreated cow, IGF-1 levels in milk range between 1 to 9 ng/mL. IGF-1 levels in the BST-treated cow range from 1 to 13 ng/mL.
Traditionally, our daily saliva IGF-1 production is equal to the amount of IGF-1 in 95 quarts of milk. Our daily whole body production of IGF-1 is equal to the amount in over 3,000 quarts of milk.
3. What are the potential effects on virus expression?
Somatotropin plays a central role in the immune system, yet, there is no evidence of elevated retrovirus prevalence in BST-treated cows or that these retroviruses pose a human health risk.
4. Is there a possible increase in health risks for neonates and children from milk consumption?
There is no sound, scientific evidence that milk poses a risk to diabetes development, as milk composition and manufacturing characteristics are unaffected by the use of BST.
Milk is a nutrient-dense food source specifically designed to deliver nutrients to neonates, noted Collier. Soy proteins have not been designed to do that.
In relation to the incidence of chronic diseases, milk consumption, regardless of whether or not the cows are treated with BST, tends to improve health maintenance and reduce the human population's chronic disease risk.
