Where Did the Mercury Come From?
Wallinga's report doesn't prove that the mercury in the tested products came from high-fructose corn syrup, but "I'm hard pressed to say where else it would come from," Wallinga tells WebMD.
Wallinga explains that mercury can be used to make caustic soda, which is one of the products used to make high-fructose corn syrup. That's outdated technology; mercury isn't needed to make caustic soda, notes Audrae Erickson, president of the Corn Refiners Association, in a statement emailed to WebMD.
Erickson didn't comment specifically on Wallinga's study. Instead, her statement focuses on a new study published online in Environmental Health, which shows mercury in some samples of commercial high-fructose corn syrup tested in 2005.
"This study appears to be based on outdated information of dubious significance," Erickson states. "Our industry has used mercury-free versions of the two re-agents mentioned in the study, hydrochloric acid and caustic soda, for several years."
Wallinga agrees about the technological shift away from mercury. "If you just look within the confines of the U.S., yes, about 90% of production now is not using mercury," says Wallinga. "The problem is that we don't actually know where our companies are buying their high-fructose corn syrup from ... it's a global industry."
"For me, the take-home message is really that this is a totally avoidable, unnecessary exposure to mercury," says Wallinga. "We've got a safer, more efficient technology for making these chemicals that are part of the ingredients used to manufacture high-fructose corn syrup."
Mercury's Form Unknown
Like Wallinga's report, the study published in Environmental Health doesn't specify the form of mercury present in the high-fructose corn syrup.
"I would imagine that a good majority of the mercury that is detected would have been in the form of elemental mercury," not methylmercury, toxicologist Carl Winter, PhD, tells WebMD. Winter, who directs the FoodSafe Program at the University of California, Davis, says that methylmercury is "by far the most toxic form of mercury" because methylmercury is better absorbed by the body than other forms of mercury.
"We have a principle in toxicology, which is the dose makes the poison," says Winter. "It's the amount of a chemical, not its presence or absence, that determines the potential for harm, and frankly, I don't see based on their findings that they've made much of a case that this is something that consumers need to worry about."
Besides his academic work, Winter is a volunteer spokesman for the Institute of Food Technologists, a nonprofit scientific society that includes food science and technology professionals in industry, academia, and government. Winter says his work has never been funded by food or chemical industries.