All cow’s milk, whether it is organic or conventional, contains tiny amounts of naturally occurring hormones. In fact, many plant and animal foods such as legumes, grains, milk, meat, and eggs contain hormones. These hormones are important to life and serve as messengers that help regulate specific functions in living organisms. No additional hormones are added to milk and the naturally occurring hormones that are found in milk are not a health concern at all.
Bovine somatotropin (bST) is one naturally occurring hormone in cows. Its physiological function is to help young cattle grow, and adult cows to produce milk. A small amount of bST is naturally present in all milk, including organic milk. A synthesized copy of bST – recombinant bovine somatotropin (rbST) – is available for farmers who choose to use the hormone as a farm management tool to boost their herd’s milk production. Health authorities such as the Food and Drug Administration (FDA) and the National Institutes of Health (NIH) have determined that milk from cows treated with rbST is both nutritious and safe and does not affect human hormones.
Still, most of the milk found at the grocery store is from cows not treated with rBST. This milk is often labeled as such. To learn more about hormones and dairy, click here.