News & Media :: Daily Log
Oh Really?
Apr 18, 2010
Need for a Watchful Eye (or Eight Eyes)
During the April 13th NYC Debate on the motion -"Organic food is marketing hype," Dr. John Krebs of the U.K. made the striking assertion that --
"There are more carcinogens [in a cup of coffee] than you would get in all the pesticide residues in eating conventionally produced..." fruits and vegetables for a whole year.
This 2010 assertion by Krebs has its roots in the long-ago thoroughly discredited work of Dr. Bruce Ames in the late 1980s on natural versus chemical carcinogens in food. Using the Ames test for mutagenc potential and an index of potential toxicity, Dr. Ames and colleagues published a series of papers concluding that there are greater risks from natural carcinogens in food than from oncogenic pesticide residues in or on food.
Ames's work did contain a nugget of truth--some natural substances in plants are indeed toxic. However, his quantitative comparisons of natural versus synthetic chemical carcinogens -- from the "cup of coffee" statement quoted by Krebs to the famous "99.99 percent of the carcinogens in the food supply are natural," quoted by Dennis Avery in the same April 13 debate--are unsupported by scientific evidence.
Ames essentially made up those numbers based on supposition, extrapolations from weak data and untestable assumptions, and no other investigators have ever come close to verifying his audacious claims. Ames's natural carcinogens argument has become a canonical example of junk science driven by ideology.
For all the details why, see the definitive, 29-page response to the Ames theory done by Dr. Ned Groth, then a technical policy director working for Consumers Union. Dr. Groth wrote the response to Ames following an exchance of letters triggered by an October, 1989 Consumer Reports story entitled "Too Much Fuss About Pesticides?".
Thanks to Consumers Union for permission to repost this important 1989 article and Dr. Groth's reply to Dr. Ames.
