The presence of hormones in our food supply has caused concern among health-conscious consumers, prompting research on the impact of artificial hormones on human health. In response to health concerns, many countries, including Canada, Japan, Australia and Japan have banned the use of hormones to treat livestock, and importation of hormone-treated animal products is prohibited in those countries. But in the United States, the FDA and the USDA continue to sanction hormone use.
Hormones in Food
Hormones are chemical messengers found naturally in all animals, including humans, that regulate numerous metabolic functions. Produced in various organs, hormones effect growth, development and reproduction. In the 20th century, scientists discovered ways to manipulate hormones in livestock to accelerate growth and increase milk production, making meat and milk production less expensive and more profitable. Today, nearly two-thirds of all beef cattle are injected with growth hormones, and 22 percent of dairy cows receive injection of rbGH, recombinant bovine growth hormone that increases milk production, according to a publication by the organization Food & Water Watch. There is concern that hormones in meat and dairy may cause adverse reactions in consumers.
Elevated IGF-1 Levels
Many concerned critics of hormones in food feel the residual hormones found in meat and dairy products might elevate levels of IGF-1, or insulinlike growth factor-1, in consumers. IGF-1 is present in human breast milk, and is important for the growth and development of babies and young children. But excessively high levels of IGF-1 have been linked to serious health problems in adults. Because it is impossible to distinguish naturally occurring hormones from those stimulated by injection, it is difficult to prove a causal relationship between meat and dairy consumption and IGF-1 levels, according to scientists at Cornell University's Sprecher Institute for Comparative Cancer Research.
Cancer
Elevated levels of IGF-1, have been linked to prostate, breast and colon cancer. A 2006 study conducted by Washington University Medical Center in Saint Louis found healthy vegetarian men to have significantly lower levels of IGF-1 than same-weight endurance athletes who consumed meat. A 2004 study found men with elevated IGF-1 to have a 50 percent higher risk of prostate cancer, and women with high IGF-1 have a 65 percent higher risk of breast cancer than their counterparts with lower IGF-1 levels. However, whether elevated levels were due to hormones in the food supply is uncertain.
Early-Onset Puberty
Many parents and educators are alarmed by the premature onset of puberty at increasingly younger ages in children. "Precocious puberty" is defined as the onset of puberty before age 8 in girls, and before age 9 in boys. Typically, puberty begins between ages 9 and 15 in girls, and between ages 11 and 17 in boys. Some suspect that hormones in meat and dairy may cause children to mature early. However, many scientists maintain that ingested hormones are destroyed by the digestive system, and do not influence human health. The rise in childhood obesity has been implicated as a potential contributing factor in early maturation of children.
References
- Cornell University; Sprecher Institute for Comparative Cancer Research; Consumer Concerns About Hormones in Food, June, 2000
- Live Science; The Truth Behind Early Puberty; Christopher Wanjek, September 4, 2007
- Huffington Post; Hormones in Food: Should You Worry?; Health.com, January 31, 2011
- Washington University in Saint Louis; Does Too Much Protein in the Diet Increase Cancer Risk?; Jim Dryden, December 7, 2006
- Foodandwaterwatch.org; Food Safety Consequences of Factory Farms
