Policy Statement: Opposition to the Use of Hormone Growth Promoters in Beef and Dairy Cattle Production, APHA, November 2009
"There is clear evidence that hormones originating outside the body can interfere with our own hormone function."It isn't just meat and dairy that may be problematic:
"Many hormone-related chronic diseases are common or on the rise, including breast and prostate cancer, thyroid disease, obesity and diabetes, endometriosis, uterine fibroids, and infertility."
"Biological plausibility and scientific findings now suggest that exogenous hormones such as those used in our food system may be one such contributor to these negative trends."
"It is widely acknowledged that the use of these hormone growth promoters results in residues in meat."In a 2007 study, for example, sperm concentration of male offspring was found to be inversely related to their mothers’ self-reported beef consumption while pregnant, with possible links hypothesized to the 6 steroid hormones routinely used in US beef production.1
"Residues of these hormone growth promoters also persist for weeks to months in manure and feedlot runoff, raising concerns about the added exogenous hormone load to the environment."The section on GMOs used in dairy cows (rbGH: recombinant bovine growth hormone) is particularly damning:
"Although some studies (including several funded by Monsanto) have failed to demonstrate that rbGH harms dairy cows, virtually all independent analyses of the data reached a different conclusion."Canada, the European Union, Australia, New Zealand, and Japan have prohibited its use. Not the US:
"In 2007, nearly 43% of large herds were treated with rbGH."
Hormone Growth Promoters Just One of Many Environmental Endocrine Disruptors
The APHA Statement referenced and echoed the Endocrine Society's Statement from last summer (that I blogged about here):
"In its first scientific statement issued in June 2009, the Endocrine Society ... determined that 'Results from animal models, human clinical observations, and epidemiological studies converge to implicate EDCs [endocrine disrupting chemicals] as a significant concern to public health. ... Scientific knowledge about [EDCs’] effects on humans . . . appears sufficient to justify societal approaches to limiting population exposures.' "Endocrine disruptors include hormones (GMO or conventional) fed to livestock as well as chemicals in plastics, pesticides, fuels, and cosmetics. EDs bioaccumulate in the food chain - they accrue in the fattier tissues of fish and other livestock. (In the future, a certification process may test animal products for ED concentrations.)
All of us have more of these chemicals in our bodies than did people just 50 years ago. Which leads me to the genetic issue...
The APHA Statement mentions epigenetic changes arising from EDs. These are changes in the activity of genes that don't require changes to the genes themselves. (Mutation is a change in a gene, the DNA itself.) Many endocrine disruptors, e.g. steroid hormones and Bisphenol A in plastics, are fat soluble and can easily diffuse through fatty cell membranes. Once inside the cell they bind to receptors and disrupt normal functioning of genes.
Epigenetic changes can cause us, a population, to experience gene-based biological outcomes - diseases such as obesity and diabetes - in a time period shorter than typical human generational cycles (100s of years). I saw that Marion Nestle is discussing Genetic Causes of Obesity on her blog. While it's true that "Obesity rates rose sharply in the early 1980s, with no possibility for so rapid a change in the genetic composition of the population," there was and is a strong possibility of epigenetic changes in this timeframe.
Maybe it's not so much the fat in our diet that's predisposing us to obesity, diabetes, heart disease, thyroid disease, breast and prostate cancer, and other hormone-related chronic diseases. Maybe it's the substances dissolved in that fat. This will be an exciting, if disturbing, area of study in the coming years.
1Semen Quality Of Fertile US Males In Relation To Their Mothers' Beef Consumption During Pregnancy, Human Reproduction, 2008