Foods made with corn syrup may deliver dose of mercury

CHICAGO — A new study suggests that food made with corn syrup could be delivering tiny doses of toxic mercury.

For the first time, researchers say they have detected traces of the silvery metal in samples of high-fructose corn syrup, a widely used sweetener that has replaced sugar in many processed foods. The study was published Monday in the peer-reviewed journal Environmental Health.

Eating high-mercury fish is the chief source of exposure for most people. The new study raises concerns about a previously unknown dietary source of mercury, which has been linked to learning disabilities in children and heart disease in adults.

The source of the metal appears to be caustic soda and hydrochloric acid, which manufacturers of corn syrup use to help convert corn kernels into the food additive.

A handful of plants across the nation still make the soda and acid by mixing a briny solution in electrified vats of mercury. Some of the toxic metal ends up in the final product, according to industry documents cited in the study.

Corn-syrup manufacturers insisted their products are mercury-free. But the study noted that at least one maker of caustic soda that has used the mercury-based technology listed the corn-syrup industry as a client.

"This seems like an avoidable source of mercury that we didn't know was out there," said David Wallinga, one of the study's co-authors and a researcher at the Institute for Agriculture and Trade Policy, a Minnesota-based advocacy group.

The researchers cautioned that their study was limited. Only 20 samples were analyzed; mercury was detected in nine.

Still, the impact of the findings could be significant. High-fructose corn syrup has become such a staple in processed foods that the average American consumes about 12 teaspoons of it daily, according to federal estimates.