Arsenic exposure poses a growing risk to pets

“Could arsenic toxicity be contributing to some of the frustrating medical problems that physicians and veterinarians see daily?”

Arsenic—it’s in our environment and in our food supply.

While it occurs naturally in water, soil and air,1 human activity has raised levels substantially. Anthropogenic sources include pressure-treated lumber, batteries, pesticides, animal feed and drugs (historically), and more.2-3 

Arsenic is highly toxic, even at low levels, and dangerous amounts have been found in the groundwater in the United States, Canada, China and Brazil. Crops grown in soil rich in arsenic may absorb the toxin. They also may be sprayed with arsenic-containing herbicides or fungicides. This adds to the levels of arsenic in water they absorb from the ground.

Short Summary

Two forms of arsenic exist: organic and inorganic. Both cause health problems,4 although inorganic arsenic compounds are more toxic and the U.S. Environmental Protection Agency classifies them as a human carcinogen.5 They enter the body through the lungs, skin and digestive tract from contaminated food and water.6 

Arsenic became a household word in 2011 after Dr. Mehmet Oz (“Dr. Oz”) clashed with the U.S. Food and Drug Administration when he announced that apple juice contained worrisome levels of arsenic, especially dangerous when fed to babies.7 The FDA reportedly vehemently disavowed evidence of any public health risk from the juices, but Dr. Oz maintained his position, claiming that almost a third of apple juice samples contained more arsenic that the limit allowed for drinking water. Two years later, the FDA, for the first time in its history, set limits for arsenic levels in food and drink products.8 

But many of the problems with arsenic have only come to light over the past decade. According to a 2007 report, “About 90 percent of the arsenic in U.S. diets comes from seafood,” although most of that occurs in the organic form.9 

A study from the University of Washington examined the arsenic content of 65 representative wines grown in the top four wine-producing locales in the United States.

Denise Wilson, the study’s author, stated in her abstract: “All samples contained arsenic levels that exceeded the U.S. EPA exposure limit for drinking water of 10 parts per billion (ppb) and all samples contained inorganic arsenic. … Lead, a common co-contaminant to arsenic, was detected in 58 percent of samples tested, but only 5 percent exceeded the U.S. EPA exposure limit for drinking water of 15 ppb. Arsenic levels in American wines exceeded those found in other studies involving water, bottled water, apple juice, apple juice blend, milk, rice syrup and other beverages.”

What About Pets?

While veterinary patients are unlikely to fall victim to arsenic toxicity linked to wine, they may be taking in excessive quantities of arsenic through regular ingestion of rice, one of the most common foodstuffs with notably high levels of arsenic. Rice plants absorb arsenic more readily than do other food crops. Arsenic concentrates in the outer shell, making brown rice more likely to show elevated levels than white rice.

Concerns about rice erupted in 2012 when researchers from Consumer Reports reported findings based on tests of over 200 rice products sold on grocery shelves. As the authors wrote in their report, “[These products] included iconic labels and store brands, organic products and conventional ones; some were aimed at the booming gluten-free market.”10 

They continued: “The results of our tests were even more troubling in some ways than our findings for juice. In virtually every product tested, we found measurable amounts of total arsenic in its two forms. We found significant levels of inorganic arsenic, which is a carcinogen, in almost every product category, along with organic arsenic, which is less toxic but still of concern. Moreover, the foods we checked are popular staples, eaten by adults and children alike.” (A full list of the products tested appears on the Consumer Reports website.11 )

Recent Proposal

This past April, following mounting consumer outrage, the FDA released new data and its scientific assessment on the level of arsenic in rice.12 While there is no completely safe level of arsenic, the FDA proposed an “action level” of 100 ppb for inorganic arsenic in infant rice cereal, given that, relative to their body weight, “rice intake for infants … is about three times greater than for adults.”

Do dogs eat rice? What about puppies? Sure they do. Whether mainstream or holistic, dog food manufacturers frequently couple rice with animal-based ingredients. This means that, day in and day out, meal after meal, dogs and puppies may be ingesting high levels of arsenic. Arsenic-heavy rice may be combined with arsenic-heavy chicken, further raising the risk of toxicity.

Until 2013, the FDA had approved the use of arsenic-containing compounds as feed additives for chickens, turkeys and hogs. Then, pressure from consumer groups forced a change. Ultimately, the FDA withdrew its approval of 98 arsenic-based animal drugs.13 

These drugs had been given as growth promoters as well as disease preventives for flocks raised in stressful, indoor, crowded conditions. A document from the Institute for Agriculture and Trade Policy described conditions before the ban: “[A]rsenic, like other antimicrobials, is added to poultry feed without a prescription. As with other antimicrobials, therefore, there are no public data to help quantify the amount of arsenic compounds being given to poultry, let alone the purpose of their use.”14 

The Great Unknown

Now, even if U.S. producers are less likely to add arsenic to chicken feed, companies overseas still could, and how would consumers know? What’s worse, dog foods made from poultry feather meal from places where arsenicals are still used could pose problems based on the accumulation of the chemical in the keratinous feather foodstuff. This practice could pose risks to humans when used as an organic fertilizer.15 

Could arsenic toxicity be contributing to some of the frustrating medical problems that physicians and veterinarians see daily? Could we resolve enigmatic disease states by ceasing prolonged ingestion of arsenic? Would some idiopathic issues disappear, including nausea, vomiting, diarrhea, stomach pain, gastrointestinal irritation, fatigue, depressed production of red and white blood cells, impaired nerve function and abnormal heart rhythm?

Might we see a downturn in the incidence of cancer of the skin, liver, bladder and lungs? Would there be fewer cases of renal disease? What other toxins are we and our animals ingesting regularly that are the causes of our ills?

References

  1. Huang G, Chen Z, Liu F, et al.  Impact of human activity and natural processes on groundwater arsenic in an urbanized area (South China) using multivariate statistical techniques.  Environ Sci Polut Res. 2014;21:13043-13054.
  2. American Cancer Society website.  Arsenic.  Accessed at http://www.cancer.org/cancer/cancercauses/othercarcinogens/intheworkplace/arsenic on 05-31-16.
  3. U.S. Food and Drug Administration website.  Arsenic-based Animal Drugs and Poultry.  Accessed at http://www.fda.gov/AnimalVeterinary/SafetyHealth/ProductSafetyInformation/ucm257540.htm on 05-31-16.
  4. Sarkar A and Paul B.  The global menace of arsenic and its conventional remediation – a critical review.  Chemosphere.  2016;158:37-49.
  5. Wilson J.  FDA proposes new rules for arsenic levels in apple juice.  CNN.  July 13, 2013.
  6. Sarkar A and Paul B.  The global menace of arsenic and its conventional remediation – a critical review.  Chemosphere.  2016;158:37-49.
  7. Associated Press.  Dr. Oz slammed over apple juice arsenic warning.  CBS News. September 16, 2011.  Accessed at http://www.cbsnews.com/news/dr-oz-slammed-over-apple-juice-arsenic-warning/ on 05-31-16.
  8. Wilson J.  FDA proposes new rules for arsenic levels in apple juice.  CNN.  July 13, 2013.
  9. Borak J and Hosgood HD.  Seafood arsenic: Implications for human risk assessment.  Regulatory Toxicology and Pharmacology.  2007;47(2):204-212.
  10. Consumer Reports.  Arsenic in your food.  Our findings show a real need for federal standards for this toxin.  November 2012.  Accessed at http://www.consumerreports.org/cro/magazine/2012/11/arsenic-in-your-food/index.htm on 05-31-16.
  11. Consumer Reports.  Results of our tests of rice and rice products.  Accessed at http://www.consumerreports.org/content/dam/cro/magazine-articles/2012/November/Consumer%20Reports%20Arsenic%20in%20Food%20November%202012_1.pdf on 05-31-16.)
  12. FDA News Release.  FDA proposes limit for inorganic arsenic in infant rice cereal.  April 1, 2016.  Accessed at http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm493740.htm on 05-31-16.
  13. Center for Food Safety Press Release.  FDA to Withdraw Approvals of Arsenic in Animal Feed.  October 1, 2013.  Accessed at http://www.centerforfoodsafety.org/press-releases/2620/fda-to-withdraw-approvals-of-arsenic-in-animal-feed# on 05-31-16.
  14. Wallinga D.  Playing chicken.  Avoiding arsenic in your meat.  Institute for Agriculture and Trade Policy.  Food and Health Program.  April 2006.  Accessed at http://www.iatp.org/files/421_2_80529.pdf on 05-31-16.
  15. Nachman KE, Raber G, Francesconi KA, et al.  Arsenic species in poultry feather meal.  Science of the Total Environment.  2012;417-418:183-188.

Dr. Narda Robinson, DVM, DO, MS, FAAMA, is an assistant professor at Colorado State University and president and CEO of CureCora, an integrative medical education center in Fort Collins, Colo. Columnists’ opinions do not necessarily reflect those of Veterinary Practice News.

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