Another Reason to Steer Away from HFCS? Some Rough Calculations

(Continuation from a previous post)

[See the update from 1/31/2009, which corrects an error in the calculations in the original post]

Last night, I took a run at calculating the mercury exposure from IATP’s residue data, using the food ingestion rates from FDA’s Total Diet Study (TDS). I obtained a maximum intake rate similar to the recently published study (my value, 23.2 ug/day, DuFault et al., 2009, 28.4 ug/day), though they are basing their calculations on a total estimated intake of HFCS, while the result I obtained was for a single carbonated soft drink (I’ll be uploading the spreadsheet with the calculations shortly). I get a somewhat higher number when I add together all of the intakes from the TDS food items, but I’m confirming how TDS results are supposed to be presented before publishing a number. Doubtlessly, the estimates of exposure will be refined as more people weigh in on this topic.

For the sake of discussion, how does a mercury intake rate from 23 to 28 ug/day compare with other estimates? The European Union in its examination of dental amalgam exposure cites an inorganic mercury intake rate of 4.3 ug/day, so the findings for HFCS would seem to be a little unexpected. A better idea will come from a comparison with EPA’s oral Reference Dose.

More analysis forthcoming.

UPDATED 1/31/2009

I found an error while doing some more work with the spreadsheet. It was a units error: IATP reports their results in parts-per-trillion, which is also expressed as picograms per gram. I had originally expressed IATP’s results as nanograms per gram, three orders of magnitude higher. Picogram per gram is one trillionth of a gram, which is consistent wit parts per trillion. Serves me right trying to do analysis around the news cycle.

This changes my results by three orders of magnitude, so the mercury intake rate for a single carbonated beverage is 0.0232 ug/day, and is well below the published value. This makes more sense now – one product made from HFCS shouldn’t provide a dose comparable to the dose from total HFCS consumption. My apologies for any misinformation that has resulted.