Back on the corn syrup

Found this article by Karl Haro von Mogel dismissing the mercury in high fructose corn syrup story via Free Vermont. There are some interesting differences between what it is says and what the mainstream press are writing.

I took a look at the paper, and the first thing that I noticed was that it was not a peer-reviewed study. So this has not passed through the rigors of experimentation, review, re-testing if needed, and publication in a scientific journal.

The Chicago Tribune says:

The study was published Monday in the peer-reviewed journal Environmental Health.

Oddly enough, another critical of the review that von Mogel also calls the paper peer-reviewed.

Moving on:

The ‘study’ itself consisted of taking samples of foods that contain high-fructose corn syrup and testing them for levels of mercury. Those foods and the brands that made them were in the report, and they found that some of the foods had detectable levels of mercury in them. What levels? Parts per trillion. These are really low levels. Drinking water has a limit of 2 parts per billion, which means that you can have 100 times as much mercury in drinking water as is in these foods. The tap water you use to make your oatmeal might have more mercury than the oatmeal itself.

Chicago Tribune again:

There is no established safe dose for elemental mercury, the type discovered in corn syrup. But the U.S. Environmental Protection Agency says an average-sized woman should limit her exposure to 5.5 micrograms a day of methylmercury, the kind found in fish. If that same woman regularly ate corn syrup contaminated at the highest level detected in the study—0.57 micrograms per gram—the researchers estimated that she could end up consuming an amount of mercury that is five times higher than the EPA’s safe dose.

This is interesting because it looks like the Tribune is deliberately confusing elemental mercury with methylmercury – two very different things. But it does give us a different look at the numbers – .57 micrograms per gram, rather than the difficult to understand parts per measurement. If I’m not mistaken, 2 ppb is 2 micrograms per liter.

Wikianswers suggests 1.5 to 2 liters of water per day. So the average person probably consumes no more than 4 micrograms of mercury from drinking water per day. That means you’d have to eat 8 grams of HFCS per day to consume the same amount of mercury.

According to Wikipedia the average American consumed 28.4 kg in 2005. Which works out to about 78 grams a day. Which sounds like a hell of a lot – am I doing the math right on that one?

If so, it means the average American could eat ten times as much mercury through HFCS than water (assuming, drastically, they are eating the worst mercury containing products). This of course is on top of water and methylmercury containing fish.

The rest of von Mogel’s article looks at the problem of the lack of controls. A very worthwhile criticism. But the report clearly says they need to do more research, and that points to the real story the FDA were warned about the potential mercury content in HFCS and did nothing. It would be unwise to conclude too much from this study other than the FDA declined to do their job.

Update: Turns out von Mogel was referring to a different paper than was referenced here recently.


  1. Scary. Yes, as far as I can tell, you’re doing the math right (assuming the Wikipedia figure is correct). That means we could be consuming 44.46 micrograms of mercury per day — .57 micrograms per gram X the 78 grams per day of HFCS.

  2. Excellent roundup, good job straightening out details.

    I know that with a lot of contaminants and “endocrine disruptors,” the problem with doing serious studies is that the pollution is so ubiquitous there’s no way to get control samples. We’re all contaminated already — background levels of pharma- and agri- compounds are truly, literally insane.

  3. There were two studies: one in a refereed journal ( and one, well, NOT (

    Karl criticized the latter, with validity… however, it’s the former study that should be of concern.
    It will be interesting to see if anyone is able to reproduce the results of their work.

  4. Kathleen – I’m still not sure how much mercury is dangerous. And the 44.46 estimate would be for people eating the specific foods with contaminated HFCS. And of course, one study doesn’t prove there’s any significant mercury content to begin with. So it could well be nothing.

    Paul – thanks for the clarification, Justin told me after I posted that article that it there were two different studies being discussed. Looks like the second one is indeed not scientific and doesn’t claim to be.

    I maintain that the real issue here isn’t that there might be mercury in HFCS, but the FDA’s failure to follow-up on the possibility.

  5. True journalism, thank you.

  6. Hi,

    I think part of the confusion is that there were two studies, one peer-reviewed and published, which tested corn syrup itself in 2005. Since then, according to the corn refiner’s association, they have switched entirely to non-mercury-involving sources of raw materials for making HFCS.

    The study that I discussed in my post was a second one, which appears to be more of a lengthy press release. That was the uncontrolled, non-peer-reviewed study that detected mercury in

    The combined effect of these two is interesting. One has the weight of being a proper scientific study, but doesn’t seem to apply anymore because it was based on 2005 data. The second, which suggests that the mercury in the food products tested came from HFCS – wasn’t even scientific. Taken together, the impression that people have been getting is that they’re both scientific and both apply to today.

    You’re right on with the relative risks. Think about the average levels of mercury in fish, at 40,000-148,000 parts per trillion of mercury – that’s quite a lot more than was found in the HFCS in 2005 and the food products today.

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