Small doses of mercury may be finding their way into high-fructose corn syrup as it's being produced, two studies released yesterday suggest.

One study, published in the journal Environmental Health, tested 20 samples of high-fructose corn syrup and found that nine of the samples contained detectable levels of mercury. The authors speculate that the mercury may have found its way into the sweetener by way of caustic soda or hydrochloric acid used in the manufacturing process. Both of these agents are commonly used in the manufacturing of high-fructose corn syrup, and are sometimes produced using mercury cells, according to the researchers.

Another study from the Institute for Agriculture and Trade Policy* tested food products that listed high-fructose corn syrup as the first or second ingredient, and detected mercury in 17 of 55 samples. You can see which products tested positive for mercury in the full study*, but the researchers note that they tested only one sample of each product, and the results should not be taken as advice to consumers.

The findings of these studies are cause for concern. Even low levels of mercury exposure can be unsafe, and several of the products that tested positive are marketed to children, who are particularly vulnerable to mercury's neurological and other negative health effects. But the total health impact remains unclear, and the studies pose more questions than answers. Were reviewing the data of these and other studies and will have an update soon. In the meantime, for more health information on these topics, see our coverage of mercury in fish, and high-fructose corn syrup.

—Kevin McCarthy, associate editor

* Links to a PDF file.