rBGH Revisited

by Kurt Seitz

This piece is from the April 2000 issue of GreenLeaf, the newsletter of the GreenStar Cooperative Market in Ithaca, New York.

Genetically modified organisms (GMOs) are very much in the news and on the minds of people concerned about our food and our environment. National chain stores and food companies are beginning to recognize the public concern over the use of genetic engineering to produce the food we eat and some are providing foods that they certify to be free of GMOs.

But before we knew what GMO stood for, rBGH was in the spotlight as a genetically engineered substance that was affecting the food we eat and had the potential to affect our environment as well. Although rBGH is no longer in the spotlight and although many farmers have decided not to use rBGH, either because it didn’t do what was promised or because they were concerned about its effects or public reaction, rBGH is still being used and is still a problem.

What is rBGH? Short for recombinant Bovine Growth Hormone, it is also known as recombinant Bovine Somatotropin hormone (rBST) and manufactured and marketed by Monsanto under the names Posilac or Nutrilac. It is a genetically engineered copy of a naturally occurring hormone produced by cows. When injected into dairy cows, their milk production increases by up to 15%. It was approved for use in dairy cows in the United States and has been in use since 1994. It has not been approved for use in any other country.

To understand how the use of rBGH affects human health and the environment, we first need to understand how it affects cows. It unnaturally causes cows to produce more milk and at the same time stresses the cows and can cause a wide range of health problems, including as much as a 79% increase in incidence of mastitis (udder infection). This results in a greater need to use antibiotics to treat the mastitis. All of this can lead to decreased resistance to disease, healing difficulty, and other disorders, as well as an increase in pus and bacteria in milk.

This brings us to the changes in milk and the potential risks to human health. As unhealthy cows produce milk, in addition to more pus and bacteria, there can also be more saturated fat, less protein, and a greater risk of antibiotic and chemical contamination of milk. (More bacteria leads to quicker souring of milk.) But the greatest risk to humans is the presence of significantly higher levels of the “Insulin-like Growth Factor” hormone (IGF-1) in milk from cows injected with rBGH.

IGF-1 is naturally produced in humans but levels decrease significantly after puberty. Cows produce more IGF-1 as their levels of rBGH increase. Although rBGH is denatured by pasteurization, IGF-1 is not. Increased blood levels of IGF-1 in humans have been linked to an increased incidence of breast, prostate, and colon cancers, as well as other cancers. IGF-1 concentrations have been found to be a greater risk factor for prostate cancer than any other risk factor.

Finally, the use of rBGH can also be both environmentally and economically detrimental. It leads to increased production of an already overabundance of milk, threatening the survival of small family farms. As the abundance of factory farms increases, the use of chemical fertilizers, pesticides, herbicides, and destructive farming techniques increases as well. And increased overproduction can result in more price supports increasing the cost to taxpayers.

What can you do to avoid consuming products that were produced using rBGH? The only guaranteed way is to eat either organic products, or dairy products that come from goats or sheep, or from outside the U.S. Although some companies have pledged that some or all of their products are produced without the use of rBGH, there is no independent confirmation of this, as there is with organic food.

March 15, 2006, update:
You can access a list of organic dairy products, as well as brands that are certified by the company and/or farmers to be rBGH-free, on the internet from the Organic Consumers Association and from Rural Vermont.

March 20, 2006, update:
Strong Demand for Monsanto's Posilac (St. Louis Post-Dispatch)

~Kurt