WASHINGTON, DC, May 13, 2013 – In a study published online Saturday in the journal Environmental Health Perspectives, researchers at Johns Hopkins University found arsenic levels in chicken that exceed those that occur naturally. Researchers also cautioned that this could translate into a small increase in cancer risk over a lifetime of eating chicken, and may result in around 124 annual deaths due to bladder and lung cancer.
Arsenic-containing drugs and feed have been allowed in U.S. chicken production since the 1940s. Approved in 1944 by FDA, roxarsone is used to prevent intestinal parasites, promote faster weight gain on less feed, and improve the pigmentation (color) of chicken meat. Feed with arsenic-containing compounds has never been approved in the EU, Japan and several other countries around the world.
According to USDA and poultry industry representatives, in 2010 an estimated 88% of the roughly nine billion chickens raised in the U.S. were treated with roxarsone.
Roxarsone contains organic arsenic, though to be less toxic than inorganic arsenic, a known carcinogen. The poultry industry has long believed that the organic arsenic was eliminated and excreted by the chickens. However, even though little is known about how chickens metabolize roxarsone, there is evidence that the organic arsenic is changing into the far more toxic inorganic arsenic inside the chicken’s body.
Chronic exposure to inorganic arsenic has been proven to cause lung, bladder, and skin cancers, and has been linked to cardiovascular disease, type 2 diabetes, cognitive deficits, and adverse pregnancy outcomes, according to the study’s authors. To reduce arsenic levels, FDA mandates that chickens not be fed roxarsone five days before slaughter.
In response to a 2011 FDA report that found higher than normal levels of inorganic arsenic in chicken livers, roxarsone was voluntarily pulled from the U.S. market by its distributor Zoetis, a subsidiary of Pfizer, but continues to be sold in other parts of the world, especially Latin America.
Members of the research team purchased chicken breasts from supermarkets in ten different metropolitan areas around the country between December 2010 and June 2011, before roxarsone was taken off the market. The study analyzed 142 chicken breast samples including 60 brands from 82 stores, of which 47 were supermarket chains. Of the samples, 69 were conventional chicken, 34 were antibiotic-free, and 37 were USDA Organic.
Roxarsone was found in about half the samples. The study found that conventional chicken contained levels of inorganic arsenic of about 2 parts per billion, while organic chicken contained about one half part per billion. Researchers estimated that if roxarsone was fed to all chickens, the exposure to inorganic arsenic could cause an additional 124 annual deaths in the U.S. from bladder and lung cancer.
Since under federal standards anything below 500 parts per billion is allowed, the National Chicken Council stated that the findings reveal “very low levels of arsenic,” which are not alarming.
“These samples, taken as part of this extremely small, agenda-driven study, were purchased before roxarsone was removed from the market in June 2011, and the conclusions are used to intentionally mislead consumers,” said Ashley Peterson, vice president of scientific and regulatory affairs at the National Chicken Council to The New York Times.
According to an FDA spokesperson, the company has assured the agency that it will not market the drug again in the U.S. without prior consultation with FDA. However, Zoetis, the company that markets roxarsone, currently sells nitarsone, a similar arsenic-based drug approved for use in chickens and turkeys. According to Zoetis spokeswoman Elinore White, scientific data supports the safety of nitarsone and the drug is not a substitute for roxarsone.
However, according to study lead author Keeve Nachman, any deliberate additive amounts to a public health risk.
Some states are listening. In 2012 Maryland passed H.B. 167, banning the use, sale, or distribution of roxarsone or any other arsenic-containing feed.
On May 1, 2013 attorneys for the Center for Food Safety, along with several other organizations filed lawsuit calling for FDA to respond to a 2009 petition to withdraw FDA approval of feed additives containing arsenic compounds.