By Rick Thomason
University of Tennessee
Johnson County Extension Director
Canada’s Beef Cattle Research Council (BCRC) has collected some interesting stats on the estrogen level in beef. A 75-gram serving of beef from cattle treated with hormone implants contains two nanograms (ng ~ one billionth of a gram) of estrogen. “A person would need to eat 3,000,000 hamburgers made with beef from implanted cattle to get as much estrogen as the average adult woman produces every day, or 50,000 hamburgers to get as much estrogen as the average adult man produces every day,” says BCRC’s science director, Dr. Reynold Bergen. “Beef is a really excellent source of protein, zinc, iron and a lot of other essential nutrients. It’s a really poor source of hormones.”
Considering there are about 45,000 ng of estrogen in 75 grams of white bread, the bun probably has far more estrogen than the beef. If you need an explanation to go with the stats, the short of it is that cattle, alongside people and all other animals and plants, naturally produce hormones that are vital to growth, development and health.
That’s why meat and plants can never be hormone-free. Some of those natural hormones are steroid hormones, which are nothing more than a class of hormones that have the distinct four-ring nuclei known as a steroid nucleus. The word “steroid” comes from cholesterol because the hormones are derived from cholesterol and transported in the bloodstream to do their work in other parts of the body. Promoting beef as raised without the added use of hormones and steroids seems rather redundant as far as beef production goes, Bergen says.
Cortisol, primarily produced in the adrenal cortex, isn’t used to improve feed efficiency or growth in beef cattle, but is one of the most commonly prescribed steroid hormones in human medicine because of its anti-inflammatory and immunosuppressive effects.
Estradiol (an estrogen) and progesterone (a progestin) are the two female sex hormones produced in the ovaries. Oral contraceptives are synthetic versions of these steroid hormones.
Testosterone, produced primarily in the testes, has an anabolic effect in people, that is, it helps repair and rebuild muscle and bone tissue. In human medicine it’s often used to treat people with wasting diseases or recovering from surgeries. Synthetic forms of testosterone were developed to give people the benefits without the unwanted side effects, mainly the development of secondary male characteristics. Synthetic steroid hormones that have this anabolic effect are called anabolic steroids. Abuse of anabolic steroids and substances that the body converts to steroids is most often associated with athletes trying to build muscle, strength and endurance, but their illegal use is also reported to be growing among teens wanting to buff up.
Beef producers don’t abuse the use of steroid hormones in beef production, as evidenced by a compliance rate greater than 99.9 per cent on residue tests. They achieve high compliance by choosing appropriate products for specific classes of cattle and using them according to manufacturers’ instructions.
Implants for beef production are commercially available in compressed pellets to be implanted under the skin of the outer ear, which is easily discarded during processing. Release of hormones from compressed pellets is rapid at first, then slows over the course of 120 to 200 days, depending on the product.
Bergen says a key point is that cattle are implanted long before they go to slaughter. By then, the implant hormone is used up. It’s also why there’s almost no measurable difference in hormone levels in beef from implanted and unimplanted cattle. There is more variation in hormone levels between male and female cattle than between treated and untreated animals. Bergen feels consumers are concerned about conventional beef production practices because they don’t understand them.