Soy and hexane - dangerous?

So I just saw a report talking about how hexane is used in soy protein isolate production – it separates the fats from the protein, apparently, and is then steamed out of the final food product. This concerns me because I eat quite a bit of the stuff. The report and video struck me as alarmist, but I think I lack the science background to fully understand what’s going on. Wanna help fight my ignorance?

I can’t seem to access the original report (by the Cornucopia Institute), but this Slate article gives a good bit of background.

This is what I believe is true: Hexane IS used in the process, most of it is steamed out (leaving up to 20-ish parts per million in the final product), and what little remains has shown no noticeable effect in lab rats over their lifespans. On the other hand, the long-term effect on human health at that dosage has not been established; the EPA is basically taking a we-don’t-know-so-we’ll-assume-it’s-safe approach.


  1. Does that seem about right or am I missing something?
  2. Does soy protein isolate/textured vegetable protein/textured soy protein (damned if I know what the differences are) necessarily go through this hexane-laden process?
  3. Who is the Cornucopia Institute? Should I have heard of them? Their website doesn’t seem to be working for me and they seem to have come out of nowhere to focus on this issue.
  4. How is the international community responding to this? Does anyone care?
  5. Can hexane be included in organic foods? (I THINK it can’t be in 100% organic food, but CAN be AN ingredient in less-than-100% organic products). Clif Bar is one example of this and their back-and-forth with the Cornucopia Institute doesn’t really clarify the situation much.

Thank you!

The Cornucopia Institute’s announced goals are to benefit organic farmers, and it doesn’t look like they’re sponsoring any research into how soy meal is processed, just repeating a warning about how Hexane Is A Petrochemical Neurotoxin.

It’s easy to point out how some chemical or other is Toxic, without providing the all-important information about dose. Otherwise you can start sounding like those people who tell us water fluoridation is deadly because fluoride is a Toxin, used in rat poison etc.

According to the Slate article, you’d have to eat more than 353,000 veggie burgers a day to get to the dose of hexane found safe in rats (and that’s assuming that none of the trace hexane volatilized off during cooking).

Soy burgers sound ecch to me, but not because of Teh Toxins.

Hexanes are relatively safe. They are a potential carcinogen but very mild at most. As i understand, its not the hexanes themselves that could cause cancer, but the oxidative breakdown products. Its not something to worry about.

I do wish that they could use diethyl ether instead, but that would be a major safety issue in production. I wonder if ethyl acetate would be non-polar enough. It’s amazing what changes like that would do to an industrial process. Hexanes may be the only thing remotely economical.

I wonder if they could switch to heptanes instead (while the discovery chemists may use hexanes, the development chemists and the plants use heptane) which has a higher ICH guideline. The permitted daily exposure under ICH guidelines is 2.9 mg/day with a concentration of 290 ppm, while heptane is considered safe at 50 mg/day with a concentration of 5000 ppm.

Do you use vegetable oil? Hexane is used as a solvent to extract canola, sunflower and corn oil too.

You are exposed to a hell of a lot more hexane in gasoline fumes when you fill up your car than you are in food.

Source. Bold added by me.

Soy- unfermented soy- by itself is not good. I’m not making this up. Research it yourself. A place to start:

Do note this, however: soy contains natural estrogen, so can be detrimental to a man’s sexual functioning.

Wouldn’t hexane inhalation, say from the fumes of chemically-extracted cooking oils, be of more concern than ingestion?

ETA: I see Implicit has mentioned cooking oils (not all of which are chemically extracted, just all the cheap ones)… but his cite again mentions inhalation only as an industrial hazard, and only considers ingestion for consumers.

And I think most of us know that huffing gasoline fumes isn’t good for the brain.

I have a little bit in the past, but last I checked the evidence was contradictory and the science rather ambiguous. Has this changed?

The Weston A Price foundation, in particular, has been the subject of criticism over their perspectives and methodology.

Quite honestly, I have no idea what to believe in regards to nutrition science; the more I read the more confused I become.

Sorry, this is a bit over my head. What’s a discovery vs development chemist, what’s ICH, and is concentration significant at all or is it the total daily dosage that matters (i.e., is 50 mg/day worse at 30,000ppm than it is at 5000 ppm?)

Good article. Thanks. Gasoline fumes as in while pumping at the station or from exhaust? How much are we talking about here?

Is inhalation more dangerous than ingestion?

And I suppose that’s where “expeller-pressed” oils come in to play?

WHO has been criticizing them… the soy industry? I find the Weston A. Price Foundation and the Price-Pottenger Nutrition Foundation to be quite credible and not at all extremist.

For example, these are the Price-Pottenger Nutritional Guidelines. Even if you don’t agree with every single last one of them (for example, if you’re a vegetarian), they’re a pretty good, sensible, tradition-based set of suggestions.

There’s a section on their Wikipedia page.

I haven’t looked into them in detail.

Sensible and traditional don’t necessarily equal scientific, healthy, or correct – though I suppose scientific doesn’t necessarily equal healthy or correct either. Some might say – though I’m not sure if I agree with this – that the meat-and-dairy-heavy diet this list advocates may have contributed to the obesity levels in this country. Yes, they advertise plenty of exercise in addition to that, but it’s given nowhere near the same amount of weight. And then a few are just… out there (why steam fruits and veggies with butter? why not use a microwave? why not drink coffee? why use spring water for cooking? why unrefined Celtic sea salt? why no low-fat milk? why no fluoridated water?)

The Weston Price Foundation has very little credibility among nutritionists and physicians due to extreme and non-evidence based positions on, among other things, soy-based foods and water fluoridation.

The link provided to “Natural Health Strategies” also provides scaremongering about aspartame and aluminum, an example of crank magnetism in action (belief in one form of health nuttiness (in this case, that soy is the Food of Evil), often is linked to the embrace of numerous quack theories*.

There is limited and conflicting information that soy may have beneficial or detrimental effects in limited subsets of the population (and depending on how much of the diet is soy-based), but there’s very little to base this sort of alarmism on.

Note also that the Weston Price people are gung-ho about us using high-saturated fat/high calorie tropicals oils, which heart experts are very wary of.

I can think of one industry that loves Weston Price - the coconut oil producers/exporters. Weston Price’s Mary Enig shows up in numerous industry forums promoting the idea that coconut oil is wonderful for you.

*We’re just panting to know how using a microwave oven damages your health.

To answer some of your questions:

n-Hexane is a known neurotoxin according to the Centers for Disease Control and Prevention. Safety studies have been done primarily by forcing rodents to inhale hexane vapors—in a review article of hexane’s safety by the chemical industry, not a single safety study involving primates or ingestion was mentioned.

Soy protein isolate, concentrate and textured vegetable protein are almost universally processed with hexane, although alternative processing methods that do not involve chemical solvents are available. Food processors opt for chemicals like hexane instead of mechanical processes because it’s cheaper and because they can get a little more oil out of the soybean.

Organic soy protein ingredients are never processed with hexane. Federal law strictly prohibits the use of hexane in processing foods that bear the Organic label (including the USDA Organic seal). Only foods with 95%-100% organic ingredients can use the “organic” label on their packaging, and these foods are never processed with hexane. However, products that use the claim “Made with Organic [ingredients]” need only contain 70% organic ingredients, and may use up to 30% non-organic ingredients that can be processed with hexane.

Hexane is the reason why some oils say “expeller-pressed” or “cold-pressed.” It’s their way of letting customers know that the oil was not processed with hexane. Another way of avoiding oil processed with hexane is by choosing organic.

Please note that Cornucopia’s report focused on products that claim to be “natural.” We find it disingenuous for food companies to label themselves as “natural” when the soy protein ingredients they use were immersed in a toxic, highly explosive, petrochemical solvent.

The Cornucopia Institute was founded in 2004 to promote economic-justice for family-scale farmers. It acts as an organic industry watchdog. With over 4,000 members it’s thought to represent more organic farmers than any other organization.

Our work has been covered by the Wall Street Journal, New York Times, Washington Post and National Public Radio in addition to many other news outlets.

Charlotte Vallaeys
Farm and Food Policy Analyst
The Cornucopia Institute

Golly, that means you’re at least as credible as Andrew Wakefield. swoons

Sorry, this thread dropped off the page for me. Basically, in the pharmaceutical industry, discovery chemists do the small-scale synthesis of lots of different molecules to test with the goal of selecting a candidate molecule to develop as a potential drug. They generally do the chemistry any way they need to, as fast and (somewhat) dirty is better than cheap and clean for their goals. Development chemists take whatever molecule was selected and work on scaling up and changing, as needed, the route to the target, with the eventual goal to be able to make it in kilogram quantities under GMP conditions and eventual scale-up to a pilot plant or full-blown plant (again, under GMP conditions.) ICH is an international guideline that basically says how much of any given solvent can be in the final product without needing to justify the level to the relevant agency (e.g., FDA). Total daily dosage matters somewhat more than the ppm, as a higher ppm could probably be justified if the overall dose was small enough to keep the total daily dosage under the guideline.

Anyway, my take was from a pharmaceutical perspective. Food chemistry is a whole different world, but I’m still surprised that they can’t make a shift to heptane unless it’s a problem with sourcing the appropriate grade of solvent without an increase in price.

And I would like to ask cvallaeys if all isomers of hexane are a known neurotoxin or just n-hexane. I would also like to know if his use of “hexane” in his post is meant to mean n-hexane or an isomeric mixture of hexanes.

IUPAC would consider “hexane” to refer only to n-hexane, as technically speaking the other isomers are methylated butanes and pentanes.

FWIW, hereis an MSDS for a 95% solvent-grade hexane which lists the health hazards for n-hexane specifically. The airborne OSHA limit is 500 ppm. The LD50 in rats by oral ingestion is 28710 mg/kg.