What’s in the corn syrup? Guest Post by Renee Dufault

In Something tastes bad…, I questioned IATP’s use of the Env. Health paper Mercury from chlor-alkali plants: measured concentrations in food product sugar. The paper described an experiment that took place in 2005. Renee Dufault, the lead author, described how she obtained samples of high fructose corn syrup and tested them for mercury. When she went back for more samples, her employer (the FDA) asked her to switch to a different project, so no more tests have been conducted. We can only hope that increased funding for the FDA will result from the recent elections and in response to the many recent threats, particularly peanut butter!

Renee has offered to discuss her experiment, her interactions with the FDA, and her reaction to the IATP report. I heartily agree with her call for more testing, but extend the call beyond mercury to include other contaminants, chemical and biological. I also agree that removing mercury from our environment should be top priority, but still feel that mercury exposure from coal-burning power plants is far more dangerous due to quantity than mercury from chlor-alkali plants. However, it certainly couldn’t hurt to switch chlor-alkali plants over to newer (non-mercury) technology!

To answer your question, “Why couldn’t one of them, or one of their grad students, continue the work?” The samples collected under my direction at the FDA were collected by an FDA field investigator directly from the HFCS manufacturers. They were collected carefully with chain-of-custody in tact. My co-authors on the paper did not work at FDA and had no way to obtain the samples. The manufacturers do not want to provide samples unless they are required to provide samples. They were required to provide the samples and cooperate with the FDA field investigator when he was sent out to collect samples. You cannot analyze samples that you are unable to obtain.

I was unable to send another FDA field investigator out to get more samples once the results were in on the preliminary mercury findings. I was instructed not to collect any more samples.

If you read the rebuttal by the CRA, then it should be clear to you that the CRA does not deny that the industry uses or ever used mercury grade chlor-alkali chemicals to manufacture HFCS.

If you have not read the Environmental Health journal article that was peer reviewed, extensively, I would encourage you to do so and take a look at the references that are mostly available on line. It should become clear to you that HFCS is but one food product manufactured with mercury cell chlor-alkali chemicals. There are others………and that is most likely one of the reasons why the IATP found mercury in food products in 2008.

I did not see the IATP report until a day or two before it was published. I knew that Dr. Wallinga was doing some follow up but I didn’t know what he was finding. I think that regardless of the flaws of his study, the important thing to know is that there are products in our food supply today that may contain small amounts of mercury. Over time, small amounts of mercury exposure via ingestion may lead to adverse health effects such as genetic variation or chronic disease. We don’t know for sure because there are no long term studies. We cannot say that small doses of mercury (regardless of form) via ingestion over time is safe. We do know, however, that it is not a good idea for pregnant or nursing women to ingest inorganic mercury because it can be passed on to the fetus, or infant in breast milk. And we also know there are sensitive populations that do not metabolize mercury effectively and these populations may easily suffer adverse effects.

And finally, if I’d had the support at FDA to test other food ingredients for mercury (such as citric acid, sodium benzoate….) I would have done it. As it was, I did all I could in the time frame I had to do it in. I did not single out HFCS, I simply started there because it was the most common ingredient found in food products.

I am certain there are many good people that work in the corn industry and I have no doubt that many if not all of these folks were unaware that the use of mercury cell chlor-alkali product in food manufacturing could lead to mercury exposure in pregnant women, infants, and children. It is time now for everyone to work together and address the issue to make sure that this source of mercury exposure is eliminated. There is no blame here. It is what it is.

I then asked: Do you really think the mercury-cell method of chlorine production is the major source of mercury in food? I don’t know much about the subject, but I was under the impression that burning coal released the majority of mercury we find in the environment. I’d love to hear more about it, both as a scientist and for my personal interest.

To answer your question, yes, I do think mercury cell chlor-alkali chemicals in food processing is a major source of mercury and that is why I fought so hard to publish the paper. Burning coal does release mercury and this does not help the situation of overall environmental mercury exposure. I believe as humans, our overall exposure to mercury from air, water and food is what is leading to the development of a number of adverse neurological effects. I am not the only scientist who thinks this way. Attached are some papers you will find interesting.

The first two articles that Renee mentioned show a correlation (not causation, of course) between autism and mercury in the environment from coal fired power plants. The last article shows that selenium, bound into selenoproteins, may bind up mercury in the body, preventing mercury from reacting with oxygen to create more dangerous compounds. Strangely, none of these have to do with corn syrup.

ResearchBlogging.orgPalmer, R., Blanchard, S., Stein, Z., Mandell, D., & Miller, C. (2006). Environmental mercury release, special education rates, and autism disorder: an ecological study of Texas Health & Place, 12 (2), 203-209 DOI: 10.1016/j.healthplace.2004.11.005

Palmer, R., Blanchard, S., & Wood, R. (2009). Proximity to point sources of environmental mercury release as a predictor of autism prevalence Health & Place, 15 (1), 18-24 DOI: 10.1016/j.healthplace.2008.02.001

Chen C, Yu H, Zhao J, Li B, Qu L, Liu S, Zhang P, & Chai Z (2006). The roles of serum selenium and selenoproteins on mercury toxicity in environmental and occupational exposure. Environmental health perspectives, 114 (2), 297-301 PMID: 16451871

Written by Anastasia Bodnar

Anastasia Bodnar is a science communicator and science policy expert with a PhD in plant genetics and sustainable agriculture from Iowa State University. Anastasia has had various risk analysis roles in US government and military service. She serves as BFI's Director of Policy and as Co-Executive Editor of the Biofortified Blog.


  1. Hi Anastasia,

    We were reading the same IATP release and discussing the work. I was baffled about the lack of clarity in the report, where the detectable level within the food product was never put into a real context for mercury toxicity. We have to remember that the article published in Environmental Health is considered a commentary, and I ask myself why it was not considered research within their publishing mandate.

    The FAO puts the upper limit exposure for mercury at 1.6ug/kg body weight. When we consider the parts per trillion mercury concentration found in the food products tested by the IATP group (published on their website, and not in the article), it then begs the question, how much food would we need to consume before mercury poisoning could be an issue. Allow me to use a 12kg child (~18 months old) as an example of a high risk consumer. The product with highest detected mercury, this child would have to consume about 50kg per day of Quaker Oatmeal to Go. The Hunts ketchup, about 180kg, and the Coke Classic, about 250L. The FAO only recently (2003, I believe) changed the upper limit on mercury exposure, and cut it by half. These are upper limit exposures, and not necessarily toxic exposures. Needless to say, I would guarantee other problems would arise from consuming large amounts of HFCS in these foods long before mercury would cause a problem.

    I agree with the principle of reducing risk, no matter what the source. And reputable food companies should have a strong priority towards quality assurance, including chemical contamination. Typical HFCS certificates of analysis may include lead or other heavy metals, and perhaps this report will encourage the industry to broaden the analysis to include mercury. It is not uncommon for the industry to drive analysis requirements.

    However, let’s return to the real issue behind HFCS. The real risk from HFCS is obesity and diabetes. Diets rich in HFCS tend to be highly processed, nutrient poor, and take the place of natural foods rich in vitamins, minerals, antioxidants and other beneficial phytochemicals which may have a protective effect against environmental exposures.

    What about the risk of fish? That is well known, and most governments have set recommended limits for women and children for large fish consumption. Fish is by far the greatest dietary exposure to mercury. But we forget that a lot of the “healthy” omega-3 enriched products, such as eggs, often come from feeding animals unnatural quantities of fish meal. The high protein value of fish meal has allowed its adoption by many livestock operations. There is more to the mercury problem than meets the eye.

  2. Tax cuts have left numerous government bureaus devoid of people to do the work. Hopefully with the new administration the neo con talk of killing government by doing away with the IRS will stop. Grover Nordquist is not in the Obama cabinet though he was behind the Republican efforts to cut all studies that would support regulation of food production be it animals or plants. I probably am taking in too much mercury since I can not find any canned fish caught and processed by USA based fisherman. Chicken of the Sea has terrible looking mackeral from China! I used to use it because it was cheap and nutritious for my children when we were very much below the poverty line. If you spend more money you can find non feed lot beef and chicken but the poor often don’t even know they should look for such food. I was an odd poor person because my late father-in-law was an avid Organic Gardening and Farming fan of the Rodale publishers.

  3. Hi, I live in Chicago and work for an environmental group here. I’m sure that many people in this city and around the country would be very interested in hearing Ms. Dufault speak about HFCS. Does she have any engagements planned? I would be more than happy to help organize an event in Chicago. I think this would be a good way to get the word out about the need for further testing.

    1. Galen,
      Since the first paper, I’ve published about finding mercury in HFCS, I’ve published another in Behavioral and Brain Functions journal that explains the relevance of low dose exposures to mercury from consumption of HFCS. What I am talking about is related to epigenetics. To combat the epigenetic factors associated with disease development, I’ve founded a non-profit called Food Ingredient and Health Research Institute. Please visit our website at http://www.fihri.org
      Thank you for your interest!
      Renee Dufault

      1. Your AP breaking news story at FIHRI has inaccuracies Renee. The Spanish cucumbers were EHEC E. coli positive. They were potentially lethal. The story categorises them as non-lethal.

  4. Galen, I’m sorry, but I’m not sure. If you are concerned about mercury, though, you might want to take a look at the papers that Renee suggested. It seems strange to me that she is concerned about the parts per trillion levels of mercury found in some foods that contain HFCS (but not all of them) but then cites papers that discuss environmental mercury from power plants. Maybe I just don’t understand the subject well enough.

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