Yesterday Kiera Butler, associate editor at Mother Jones, posted an article claiming that soy-based veggie burgers and infant formula are “made with the chemical hexane, an EPA-registered air pollutant and neurotoxin.” She based her conclusions on a report put out by The Cornucopia Institute, an organization committed to “ecological principles and economic wisdom underlying sustainable and organic agriculture.”
If you’ve heard about hexane before, it was likely in the context of gasoline–the air pollutant is also a byproduct of gas refining. But in 2007, grain processors were responsible for two-thirds of our national hexane emissions. Hexane is hazardous in the factory, too: Workers who have been exposed to it have developed both skin and nervous system disorders. Troubling, then, that the FDA does not monitor or regulate hexane residue in foods. More worrisome still: According to the report, “Nearly every major ingredient in conventional soy-based infant formula is hexane extracted.”
I’ve used hexane before (technically known as n-hexane) in various laboratories I’ve worked in as a powerful cleaning agent. It’s highly toxic and the Department of Health and Human Services states that “Inhaling n-hexane causes nerve damage and paralysis of the arms and legs.” Most of my life I’ve been largely unconcerned about what I eat (we’re all going to get cancer one way or another), but since I’ve become a new parent I try to be conscious of what I’m feeding my baby. So this report naturally caught my eye. But is it true?
The EPA Federal Register from 2001 (pdf here) identifies industrial use of the chemical in vegetable oil extraction with “major sources” of hazardous air pollution (it’s also considered a concern for workers exposed to the chemical). Those who choose to be vegetarian often do so for environmental reasons, so for this fact alone it would seem that organic products (that by definition don’t use hexane) would be more consistent with their worldview.
The Cornucopia Institute report, entitled “Behind the Bean,” states that their research:
exposes a “dirty little secret” in the natural foods business–the widespread use of a toxic and environmentally damaging chemical, hexane, in the manufacturing of “natural” soyfoods such as vegetarian burgers, nutrition bars, and protein shakes.
They base this conclusion on two pieces of evidence:
- “According to EPA reports, small quantities of solvent (up to 0.2 percent by volume of oil) can be present in oil after extraction.”
- “A Swiss team of scientists tested various oils and found hexane residues in some of the tested oils.”
Hexane evaporates rapidly in air, but it is possible that some could be retained in the extracted oil. However, in looking up each of these sources I found the first to be correct and the second to be exaggerated. The EPA reports (pdf here) that “Small quantities of solvent (up to 0.2 percent by volume of oil) are present in the crude vegetable oil after the solvent is recovered by film evaporators and the distillation stripper.” However, the results from the Swiss scientists (pdf here) could only be interpreted as they were in a very loose fashion:
No samples were found to exceed the tolerance value of 1mg/kg for the solvent hexane. The highest concentration was found in a macadamia nut oil, nevertheless, at 0.13mg/kg it was much lower than the tolerance value. No hexane was detected in 88% of the samples. The limit of detection for hexane is about 0.01mg/kg.
The Cornucopia report also claimed that samples of hexane-extracted soy oil, soy meal, and soy grits were sent to an indepentent USDA lab for analysis:
While there was less than 10 ppm hexane residue in the oil, both the soy meal and soy grits contained higher levels of hexane residues. The soy meal contained 21 ppm hexane and the grits contained 14 ppm. These tests raise important questions regarding the presence of hexane residues in everyday foods.
The results of this test were not made available so there’s no way to verify the information. However, it is true that the EPA does not monitor consumption of hexane in consumer food products and the process is used, not only for all soy based products, but also for nut, cottonseed, and olive oils. This fact supports the concern stated in their report about infant formula:
We believe that this research is especially important given the fact that most soy-based infant formulas contain ingredients that have been hexane extracted. In fact, nearly every major ingredient in conventional soy-based infant formula is hexane extracted. Infants consume much greater quantities of food compared to their body weight than adults, and formula-fed infants consume the same foods day after day, for many months. If hexane residues are present in conventional soy-based infant formula, their effects on infants should be investigated.
With a background in primatology, this is obviously not my primary area of expertise. However, given that it has been shown that trace amounts of hexane remain after the extraction process, and given that the effects on human health are unknown, it would seem that learning more about this and monitoring its presence in our food is an excellent idea. Neurotoxin in our veggie burgers? Hardly. A reason to pay an extra buck for organic infant formula? Probably not a bad idea.