Ask Dr. Dairy: Should I be concerned about hormones in milk?

  • Article
  • 2 min read February 13, 2018

While all cow’s milk, from organic to conventional, contains tiny amounts of naturally occurring hormones, the current evidence shows that milk is safe.

Most living things, including plant and animal foods such as legumes, grains, milk, meat and eggs, contain hormones, which can be thought of as messengers that help regulate specific functions in plants, animals and people. Hormones are important to life.

Many hormones are proteins, so when they’re eaten as a part of foods, enzymes in the gastrointestinal tract digest them, which stops their biological activity in the body. Therefore, naturally occurring hormones in milk are not a health concern. No hormones are added to milk.

One naturally occurring protein hormone in milk – bovine somatotropin (bST) – is present in cows and helps to regulate normal growth and development. Although bST is found at a very low concentration in cow’s milk, this hormone is only active in cows and is not recognized by the human body. The Food and Drug Administration approved the use of the synthetic version of this protein, called recombinant bovine somatotropin (rbST), that some dairy farmers use to increase milk production.

The synthetic hormone helps cows produce milk more efficiently by using fewer environmental resources, such as feed and cropland. According to scientific experts, giving rbST to cows does not meaningfully alter the composition or nutritional quality of their milk.

Speculation in the early ‘90s that hormones in milk might be the cause of early puberty in children has led to misconceptions about milk that current science does not support. In fact, there is no conclusive evidence that drinking milk or eating other dairy foods (or any particular food) is associated with early puberty. The scientific community has investigated the link between higher rates of childhood obesity and pubertal development in females, but more research is needed. Milk provides important nutrients for children’s growth and development, such as calcium and vitamin D, especially as they reach their peak bone-building years in adolescence.

Today people have many food choices available to them. Health and wellness professionals can help people make an informed choice about milk. The bottom line is milk and other dairy foods are safe and nutritious foods you can recommend to others and enjoy with confidence.