Food Scares and Rodent Testing

We see these startling headlines every day: Limonene in oranges causes kidney cancer in rats! Alar in apples causes cancer in mice! The sweetener saccharin causes bladder cancer in rats! These reports usually focus on a chemical present in the environment that produces cancer in a laboratory animal test with the implication that it will also cause cancer in humans. The question is—what are we to believe about the headlines making a connection between animal studies and potential effects on humans? (1)

In the laboratory many of these chemicals are tested at very high doses that produce cancer in test animals, and yet they do not pose a risk to humans at the levels to which we are exposed. In the assessment that the EPA makes to decide what dose to humans may have a hypothetical one-in-a- million chance of causing cancer, the animal receives an average 380,000 times that human dose. (2) This is done because researchers have to identify in a relatively short period of time what is generally a low incidence of cancer development. How high are the doses? Here are examples that read like something you would expect to see in Mad Magazine:

• - Saccharin given to rats was the equivalent of a person drinking 800 cans of diet soda in a day. (3)
• - With safrole, one would have to drink 613 (12 oz) bottles of root beer daily. (4)
• - A 155 pound person would have to eat 82,600 slices of bread every day for a lifetime to be exposed to a dose of furfural comparable to that which causes cancer in rodent tests. (5)
• - A person would have to consume 2.5 million bottles of Perrier mineral water containing benzene (20 ppm) each week to approximate intake that had sickened rodents. (6)
• - Someone of average body weight would have to eat 35,000 potato chips (about 62.5 pounds) per day for life to get an equivalent dose of acrylamide as lab animals. (7)

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Lois Swirsky Gold and her colleagues report: “Evidence is accumulating that cell division caused by the high dose itself, rather than the material being evaluated, is increasing the carcinogenic effects and, therefore, the positivity rate. High doses can cause chronic wounding of tissues, cell death, and consequent chronic cell division of neighboring cells. This is a risk factor for cancer because each time a cell divides, the probability increases that a mutation will occur, thereby increasing the risk for cancer. At the low levels to which humans are usually exposed, such increased cell division does not occur.” (8) Also, it is important to remember that mice and rats are not little people. Steven Austand notes, “Any medical research specialist can give you chapter and verse on how rats and mice differ from humans, be it heart, kidney, brain or muscle function. Rodents have vastly different dietary requirements than humans. They are poisoned by some chemicals that are harmless to humans and vice versa.” (9) Here are some specific differences between rodents and humans:

• - Rats and mice do not undergo anything similar to human menopause. (10)
• - Rats have no dietary source of ascorbic acid and they have no gallbladder. Their six pairs of mammary glands suggest an increased likelihood for tumor development compared to humans. (11)
• - Rodent strains are specially bred to be prone to cancer (Sprague-Dawley rats, Fischer rats, and B6C3Fl mice). (12)
• - Rats are unable to vomit, so when a rat ingests a toxicant, it is unable to expel the material from its stomach. (13)

Summary

The contributions of animal research to health, safety, and well-being of both humans and animals have been enormous. Without animal research, very few of the medical advances we expect today for ourselves and our loved ones would be possible. However, high does testing of rodents for chemical toxicity is another issue by itself. The Wall Street Journal sums up high does testing of rodents in this fashion: “The net result of this type of research is that thousands of harmless substances are branded as carcinogenic. Everything from dioxins to diesel exhaust has been shown to cause cancer in these poor creatures and are, therefore, branded by the EPA potential carcinogens. The costs to industry, and hence the ordinary consumer, are vast. The only people who benefit are the junk scientists and their patrons, the bureaucrats.” (14) Jack Dini Livermore, CA References 1. Samuel Cohen and James Klaunig, “Chemical X causes cancer in lab rats. So what?”, realclearscience.com, July 29, 2015 2. Michael Fumento, Science Under Siege, (New York, Quill, William Morrow, 1998), 46 3. David L. Faigman, Legal Alchemy, (New York, W. H. Freeman and Company, 1999), 145 4. “Of Mice and Mandates,” American Council on Science and Health, July, 1997 5. Elizabeth M. Whelan, “Traditional carcinogens for the holidays, anyone?”, Environment News, 3, 3, January 2000 6. Jeff Wheelwright, Degrees of Disaster, (New York, Simon & Schuster, 1994), 149 7. Steven Milloy, “Junk science oscars,” foxnews.com, December 27, 2002 8. Lois Swirsky Gold et al., Misconceptions About the Causes of Cancer, (Vancouver BC, The Fraser Institute, 2002), 32 9. Steven N. Austad, Why We Age, (New York, John Wiley & Sons, 1997), 187 10. Steven N Austad, Why We Age, 179 11. Bernard L. Oser, “The rat as a model for human toxological evaluation,” Journal of Toxicology and Environmental Health, 8, 521, 1981 12. John Brignell, Sorry, Wrong Number!, (Great Britain, Brignell Associates, 2000), 114 13. M. Alice Ottoboni, The Dose Makes the Poison, Second Edition, (New York, Van Nostrand Reinhold, 1997), 56 14. “Mouse terrorism,” The Wall Street Journal, A18, June 1997