There have been a number of recent questions about hormones in meat and milk. Here are some answers, with some help from the CommonGround program, a great resource for many questions about food.
First, federal regulations allow hormones to be used on cattle and sheep, but not on poultry or hogs, so there are no added hormones in chicken or pork. Sheep producers generally do not use hormones, so hormone use is mostly limited to beef and dairy production. The oft-discussed increased size of chicken breasts is due to a combination of advancements in genetics, feed and improved production practices — not hormones. It should be noted, though, that no meat or dairy products are hormone free, as all animals have naturally occurring hormones in their systems. Growth hormones are sometimes used in meat and dairy production to safely increase milk output per cow and produce leaner meat products more efficiently.
Bovine somatotropin (BST) serves as a protein hormone that is produced naturally by cows to help them make milk. A minority of dairy farmers, about 15% of farms, use small amounts of synthetic BST to increase the milk production of their cows. The American Medical Association has said BST does not harm cows or alter the
nutritional value of the milk.
With milk, pasteurization destroys 90% of hormones. The rest of the hormones are broken down during digestion. No differences exist between milk produced by hormone-treated and untreated cows, according to FDA studies.
To put hormone use in beef into the proper perspective, you need to look at the numbers. The Center for Veterinary Medicine has confirmed that 1 pound of farmed beef from cattle given a common hormone, estradiol, contains 15,000 times less estradiol than the estrogen produced daily by the average man and 9 million times less than that produced by a pregnant woman. Three ounces of beef from a steer that has not been treated with hormones has an estrogenic level of 1.2 nanograms. Three ounces of beef from a treated steer has an estrogenic level of 1.9 nanograms. A bowl of spilt pea soup has 908 nanograms and there is an estrogenic level of 2,700 nanograms in four ounces of cabbage. And, it is important to note that, of the hormones ingested in food, only 10% are absorbed by the body.
Agricultural hormone use has been found safe by scientists all over the world. Residue levels of hormones in food have been demonstrated to be safe and well below any level that would have a known effect in humans, according to FDA.
There are numerous consumer concerns about the hormones in food, especially in milk, leading to early puberty in children, though there is no scientific basis for these concerns. A report published in the Journal of the American Dietetic Association states girls enter puberty today at younger ages than they did 30 years ago. But the reasons why remain unclear and other evidence shows that the age of the onset of puberty in girls has been decreasing since the mid-1800s.
Some scientists believe that childhood obesity may lead to earlier onset of puberty. But no research shows that milk or dairy products play a role in early puberty. Unfortunately, girls today drink less milk than their mothers did. FDA has concluded that milk produced by hormone-treated and untreated cows proves to be exactly the same.