Hormones in milk, beef, could put kids at even higher risk
October 12, 2007
Kathryn Perrotti Leavitt/Children’s Health Environmental Coalition
Rose Welch has a 3 1/2-year-old son Adrian who was breastfed for the first few years of his life and now drinks only organic milk and eats only organic food. Rose worries about the hormones used in meat and dairy production. “The amount of chemicals [and hormones] in our food are horrifying,” says Rose. “And none of the statistics are kept on kids.”
Rose is particularly concerned about recombinant bovine growth hormone, or rBGH, (sometimes referred to as rBST, or recombinant bovine somatotropin), which is used in the milk industry. In 1994, the U.S. Food and Drug Administration (FDA) approved rBGH for sale over the objections of consumer and health advocacy groups, such as Consumers Union and Cancer Prevention Coalition. rBGH, a genetically engineered growth hormone, was not approved for use in both Canada and Europe due to animal welfare and human health concerns.
Farmers use rBGH to increase their cows’ milk output by as much as 25 percent, and the drug is injected into anywhere from 5 percent to 30 percent of the cows in the U.S., according to its manufacturer, Monsanto. Though Monsanto contends that milk produced with rBGH is no less safe than non-rBGH milk, others disagree.
Use of rBGH increases Insulin-like Growth Factor-1 (IGF-1) in the milk of treated cows–by as much as 10-fold. Though IGF-1 naturally occurs in both humans and cows, higher than normal levels of this substance in humans has recently been linked to breast and prostate cancers. There is no definitive proof that drinking milk with high IGF-1 levels will translate to high levels in humans, but IGF-1 can be absorbed into the bloodstream from the digestive tract.
rBGH-treated cows also suffer higher rates of mastitis, an infection of the udder. Milk from infected cows can be contaminated with pus and bacteria and require treatment with antibiotics.
“There are a lot of unknowns around rBGH, and if you look at it in terms of risks and benefits, there’s absolutely no benefit for humans,” says Michael Hansen, Ph.D., a research associate with Consumer Policy Institute, a division of Consumers Union. And, as Dr. Hansen points out, “Children drink a lot more milk per unit of body weight than adults.”
Beefing Up on Hormones
Many other hormones are used by farmers to raise their animals faster and more efficiently. Much of the controversy surrounds beef, since hormones are given to more than 90 percent of cows in the U.S. The FDA permits six hormones to be given to livestock. Both livestock and humans naturally produce three: estradiol, testosterone and progesterone. These hormones are also reproduced from plant hormones in the laboratory. Trenbolone acetate, melengestrol acetate and zeranol are synthetic hormones used on animals.
The FDA has concluded that the amount of hormone residue in our food is negligible compared to the amount that the body produces naturally. Nevertheless, two hormones–estradiol, a type of estrogen, and progesterone–are considered probable carcinogens by the National Toxicology Program at the National Institutes of Health. Estrogen has been linked with breast cancer in women and testosterone with prostate cancer in men, while progesterone has been found to increase the growth of ovarian, breast and uterine tumors.
When it comes to animals other than cows, the situation isn’t quite as grim. According to the FDA’s National Center for Veterinary Medicine, no hormones are approved as growth promoters for chickens or pigs (zeranol is approved for fed lambs). And while farmers also use another category of hormones called estro-synchronization products, designed to make animals give birth at the same time, these are approved only for sheep and cattle and, again, not for chickens and pigs.
As for frequency of illegal use of hormones, that’s something no one can know for sure. The U.S. Department of Agriculture (USDA), the agency responsible for overseeing meat production, does no testing for natural hormones and only sporadic testing for the synthetic hormones. Still, illegal hormones have been found by more rigorous testers, such as the Swiss who, in 1999, detected diethylstilbestrol (DES), the cancer-causing, anti-miscarriage drug, in two shipments of American beef. The FDA banned the use of DES for growth promotion in chicken and lambs in 1959 and in all animal feed in 1979.
The use of growth hormones is banned in Europe, and the European Union Scientific Committee for Veterinary Measures has stated that all sex hormones used in the United States could pose a risk of cancer and “that children are most at risk.”
Can Hormones in Food Harm Kids?
To date, no specific studies have been done on the health effects of hormones in food on children, who can be more vulnerable to substances that don’t harm adults. Because children have relatively low natural levels of the sex hormones in their bodies, some experts believe that even small increases are cause for concern. “The younger you are [when exposed], the greater the risks,” says Samuel Epstein, M.D., professor of occupational and environmental medicine at the University of Illinois Medical Center and founder of Cancer Prevention Coalition.
Some experts, such as D. Lindsey Berkson, author of Hormone Deception (Contemporary Books, 2000), worry that hormones in the food supply could be at least partly responsible for early puberty. The average age for a girl’s first period is now between 12.5 to 12.9 for white girls and around 12.2 for black girls, younger than at the turn of the century, though by how much is not known conclusively. However, at this point, a link between hormones and early puberty has not been established by researchers.
What about natural plant estrogens, or phytoestrogens? These substances, found in many foods, such as whole grains, pumpkin, zucchini, carrots, garlic, cabbage and soy, have a mild estrogen-like effect. In the end, though, phytoestrogens aren’t nearly as worrisome as the hormones given to animals.
In the face of all that’s unknown about hormones in our food supply, a cautious approach may be warranted. Limiting your child’s intake of hormones from food can be done fairly simply.