Growth Hormones in Food Animals
Diet & Nutrition

Growth Hormones in Food Animals: What’s the Risk?

In particular, EDs affecting estrogens have been studied because elevated doses of estrogen hormones such as estradiol may cause premature sexual development in girls, including earlier maturation of breasts. Studies relating to the development of breast cancer have also been tied to exposure to estrogen-affecting EDs.

Many EDs have been labeled carcinogens as well. Science has shown that endocrine disruptors increase the risk for reproductive harm, premature sexual development, and diseases including cancer.

The challenge is whether or not hormones in our meat are truly endocrine disruptors, and what is an “acceptable level” if they are. Researchers are mixed on this point since it is difficult to pinpoint the precise effect on people given that they not only already have these hormones naturally in their bodies but also may be impacted by other endocrine disruptors in the environment or in foods other than meat.

An example of the complexity of the problem is a study of how meat prepared in fast food environments may contain EDs. Is the endocrine disruptor the hormone-fed beef? The GMO-feed the beef was fed? Is it other ingredients or high-heat cooking which may introduce endocrine disrupting chemicals? Is it the plastic chemical residue that comes from exposure to the cook’s protective gloves? Is it the packaging in which the food is delivered? There are just so many possible variables. This study found that children who got at least 35 percent of their calories from fast food had higher levels of endocrine disruptors in their urine. Yet with the toxic soup of possible EDs, to what extent is the beef the culprit?

Implications to children – premature sexual development?

Recent studies have shown that there has been a progressive decrease in the age of puberty onset in children. Most researchers agree that this is likely due to a combination of genetic, environmental, and endocrine factors.

Several EDs such as pesticides, phthalates, topical and natural estrogens, and phytoestrogens have been pointed to as possible agents affecting pubertal development in children. Some chemicals have actually been banned as they have been linked to affecting precocious puberty.

Chemical flame retardants have been linked to earlier menstruation. Pesticides and even hair products have been linked to earlier pubertal development. High levels of dioxin have been associated with increased risk for breast cancer.

Many different EDs have been found in urine of US girls when tested. In particular, bisphenol A (BPA – found in many plastics and the lining of canned foods) and phthalates have been routinely found in studies.

Phthalates have been found to trigger “death-inducing signaling” in boys’ testicular cells, making cells die abnormally early. Studies have also linked phthalates to lower sperm count, birth defects in the male reproductive system, thyroid irregularities and a variety of other disease states.

But what about hormones found in meat?