Meat contains estrogen naturally, but in addition, most livestock farms treat cattle with various synthetic hormonesincluding estrogens. Its influence on the estrogenic content of the diet and its effects on health is a controversial debate without clear data.

What are estrogens?

Estrogens are steroid hormones found naturally in mammalian animals, including humans. These estrogens produced by the body itself are often known as endogenous estrogens to differentiate them from exogenous estrogens, which are incorporated into the body from the outside, for example through the diet.

Estrogens are involved in the development of female sexual characteristicsThey regulate the menstrual cycle and are also produced by the placenta during pregnancy. In addition to these functions, estrogens are involved in the functioning of the thyroid and in the regulation of metabolismnot only in women but also in men, affecting the growth, bone metabolism and body weight control.

Excessive estrogen levels have been linked to some types of cancer, especially breast and endometrial cancer.

Synthetic estrogens in meat

Most farms administer synthetic estrogens to cattle to take advantage of their effects on metabolism and stimulate animal growth. Estrogen-treated cattle can grow between 10 and 30 percent more than untreated cattle.

In addition to estrogens, the industry uses other synthetic growth-promoting hormones. All of them can be found at small amounts in marketed meat products, including meat, without being able to differentiate from natural hormones and in concentrations similar to those found in meat from untreated animals.

Some of the synthetic hormones, such as zeranoldo not occur naturally in any animal and can be found in trace amounts in meat.

The low amounts and the difficulty of differentiating the origin of some of the hormones, makes almost impossible to establish clear regulations about it by the health authorities.

Some academic sources, such as the University of Kentucky College of Agriculture, maintain that the use of growth-promoting hormones in livestock has been extensively studied for safety and that the difference in hormone concentration is very slight between treated and untreated animals.

Red meat and breast cancer

There are a large number of studies on red meat and its relationship with the development of cancer, which is why the WHO included this food in the list of carcinogenic products along with processed meat products.

Specifically, the consumption of red meat could be related to breast cancer, as was concluded in a large study conducted by Harvard Medical School on 90,000 women for 12 years. The women with the highest consumption of red meat had up to twice the risk of breast cancer. This association has been consistent with the conclusions of many other studies on the subject.

The association between meat consumption and increased risk of cancer has been related to the level of estrogenic hormones present in meatboth those of synthetic origin and those of natural origin, which stimulate endogenous estrogen synthesis increasing the risk of breast cancer. This stimulation of the endogenous synthesis of estrogens is also related to a high consumption of fat, which occurs in meats, dairy products, fried foods or even some vegetable oils and fats,