You will often see meat and dairy labels that say, “no added hormones,” or something like that. But, what exactly are they talking about? And what hormones should we be looking out for? Here is the FDA approvedlist:
1. Estradiol-sex hormone, current form used in cattle has been linked to increased levels of breast cancer
2. Progesterone-sex hormone used to increase fertility
3. Testosterone-sex hormone used to increase weight gain in cattle. Most cattle are castrated and the supplement is used to “make up for” the lack thereof.
4. Zeranol-sex hormone that increases growth in animal. Studies have linked some connection with increase in breast cancer and onset of puberty in humans (http://www.breastcancerfund.org/clear-science/chemicals-glossary/zeranol.html)
5. Trenbolone aka “Fina”-steroid used to increase growth and appetite in cattle.
6. rbGH-(Recominant Bovine Growth Hormone) Synthetically derived growth hormone developed through DNA technology in the 1980s. Given to dairy cows to produce more milk for longer periods of time.
Side effects on animals: clinical mastitis, reduction in fertility, increase in lameness and deformities.
Side effects on humans: stimulates production of insulin-like growth factor 1 (IGF-1) which can has been correlated with the growth of human cancer cells.
Honestly, it is difficult to find enough solid, biased-free research on these topics. What I do know is that it is likely we are consuming these hormones if our cattle have been treated with it. Again feedlots are very unsanitary, so not only are they being treated with these hormones via implants, but they excrete them and then likely consume them again. It is very hard to prove an exact cause and effect. But parties opposed to the use of these hormones would suggest they cause problems for human endocrine systems in general, because IGF-1 interacts with estrogens, androgens, and other growth promoters. Also, some would suggest they are increasing the rate of breast cancer and causing premature onset of puberty.
In the 1970s breast cancer had a lifetime risk of 1 in 10, currently, it’s 1 in 8 (http://www.cancer.gov/cancertopics/factsheet/detection/probability-breast-cancer), and incidences in ages 20-30 years old has increased considerably in the last 5 years. Different sources say different things, but they all agree that breast cancer has become the second leading cause of death by cancer in women, right behind lung cancer (third behind heart disease). Prior to the 1970s I don’t know, but the use of at least one of these hormones became FDA approved as early as the 1930s and most were mainstream by the 1980s.
As for the puberty thing, what is now being called “precocious puberty,” is the definitive onset of puberty before the age of 8 in girls, and the age of 9 in boys (http://www.mayoclinicom/health/precocious-puberty/DS00883/DSECTION=risk-factors), and risk factors include being exposed to sex hormones at an early age. Also, the human body has a trigger based on bodyweight for when to start puberty, and exposure to growth hormones would affect this process.
But this is only tapping the surface of research that could be done regarding how exactly endocrine disrupters in food affect human development and health. The truth is we encounter endocrine disruptors ubiquitously in our enviroment from what bath products we use, to chemicals in our carpet at home. So reducing exposure in our food is probably one of the simpler things we can make a change with.
What to look for:
1. "No added hormones."
2. "Pasture raised."
3. Grass fed usually implies an environment where hormones are not used.
4. Go raw (for milk): http://www.rawmilkcolorado.org/
Food for thought!