Are there harmful levels of mercury in High Fructose Corn Syrup (HFCS)?

I was first alerted by this article which claims:

She was then promptly shipped a big vat of HFCS that was used as part of the study that showed that HFCS often contains toxic levels of mercury because of chlor-alkali products used in its manufacturing.


High fructose corn syrup is always found in very poor quality foods that are nutritionally vacuous and filled with all sorts of other disease promoting compounds, fats, salt, chemicals and even mercury.

A further web search turned up this 2009 article in Environ Health. Extract:

Mercury cell chlor-alkali products are used to produce thousands of other products including... high fructose corn syrup. A pilot study was conducted to determine if high fructose corn syrup contains mercury...

The samples were found to contain levels of mercury ranging from below a detection limit of 0.005 to 0.570 micrograms mercury per gram of high fructose corn syrup.

Is there any evidence to suggest mercury at the levels mentioned in the research above are at a harmful level and are uncommon as compared to other processed foods?

  • This report, showing low but detectable levels of mercury (of an unknown type which, alas, is relevant) is from a lobby group, not a peer-reviewed journal. The results garnered a lot of criticism. They attempted to address the criticism, but I think it just showed more research was required to resolve it.
    – Oddthinking
    Aug 16, 2011 at 13:08
  • Actually, that last link shows that there are 5 plants using mercury in the USA, and the EH link indicated they lose about 7 tons a year. That adds up to 35 million grams annually, or about 100.000 micrograms per American. That's quite a bit of mercury to go missing.
    – MSalters
    Aug 16, 2011 at 14:35
  • @MSalters How is 7 tonnes equal to 35 million grams? For non-metric readers 1 tonne=1,000kg and 1kg=1,000g. Thats why calculations are easier ;-). It is also < 25mg per person not the 100mg you calculate. That would be a lot if you ingested it or inhaled it, but that isn't where it goes, i suspect.
    – matt_black
    Jan 7, 2014 at 22:46

1 Answer 1


Well, the linked article is rather clear: With up to 50 grams of HFCS consumed at .5 microgram, the daily intake would be 25 microgram. Mercury is a danger to unborn children [...] if they are exposed to low dose microgram exposures.

This is of course a worst-case scenario. The same chlor-alkali chemicals are increasingly produced without mercury at all, which would explain why some batches of HFCS had no detectable mercury at all (11 out of 20).

Another relevant comparison might be to fish, where the limit is one microgram of mercury per gram of fish (1 ppm). The concentrations found in HFCS are significantly less than that, even in the worst case.

So, there is a scientific basis for the claim, although the details (often contains toxic levels of mercury) are still dubious.

  • yah, the nih study shows clearly that there's nothing to worry about, and huffpo isn't exactly known for scientifically (if at all) accurate "reporting".
    – jwenting
    Aug 16, 2011 at 10:55
  • @jwenting, I don't think the NIH study shows that at all: "Mercury contamination of food products as a result of the use of mercury contaminated HFCS seems like a very real possibility. [...] this potential source of mercury may exceed other major sources of mercury [...] Food products that contain a significant amount of HFCS should be tested for mercury contamination in the end product and the public should be informed of any detections. Clearly, more research is needed to determine the extent of mercury exposure in children from mercury contaminated HFCS in food products."
    – Oddthinking
    Aug 16, 2011 at 13:03
  • 2
    @OT see the numbers. The nih study shows levels way below those considered harmful. And that's the crux, the dose makes the poison. At any level of ingestion of hfcs that the amount of mercury contamination woud become dangerous you'd have far more serious problems to worry about.
    – jwenting
    Aug 17, 2011 at 8:17

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