cattle and sheep
Diet & Nutrition

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

In sheep, three hormones are used primarily to control reproduction: progestogens, estrogens, and gonadotropins.

Researchers, including the FDA, agree that residues from these growth hormones can remain in meat after slaughter and also remain in the environment. Studies have shown that residual hormones such as trenbolone have found their way into local streams, and that these hormones have impacted normal reproductive functions and behavior in fish.

The FDA believes that the level of hormones found in grocery meats is well below any level of health concern. The administration points out that the steroid hormones given to cattle and sheep are also found naturally in these animals. Even without adding additional hormones, there are already estradiol, testosterone, and progesterone hormones in our grocery meat. The FDA says the natural and added levels of hormones in meat are acceptable.

While legal in the US, the use of certain steroid hormones in beef production is illegal in Europe, where it is banned based on concerns relating to potential impacts on people’s endocrine systems. European public health officials have said that even residual amounts of hormonally active compounds found in meat may have potentially adverse effects to public health.

They use what is called, “precautionary principle”. This means they want to protect people from being exposed to a risk before there is complete scientific proof that the risk exists. They feel any potential risk is just too great.

Many researchers disagree with the FDA’s stance and believe these incremental hormones act as damaging “endocrine disruptors” (EDs).

What’s an endocrine disruptor and why is it so dangerous?

The human endocrine system consists of the glands in our bodies that produce our hormones. Hormones regulate metabolism, tissue function, sexual function and reproduction, growth and development, sleep, and more.

It is well established that various toxic chemicals called endocrine disruptors (EDs) that people can be exposed to in the environment can affect their hormones. EDs can imitate natural hormones in the body and interfere with normal signaling. Of particular concern is that EDs mimic naturally occurring hormones such as estrogens, the female sex hormone. This can result in an increase or decrease in normal hormone levels or can alter the natural production of hormones.

So what does this mean? This hormone disruption can cause changes in metabolism, impair immunity, slow cognitive development, and result in fertility problems or even cancer.

One example of an endocrine disruptor many people have heard about is a drug called diethylstilbestrol (DES) that was given to some five million pregnant women to promote healthy pregnancies. It was later discovered that the DES had affected the normal development of the reproductive system in the fetuses, causing vaginal cancer. This is a great example of how impacts in endocrine function during early states of life can have major effects.