Let me start by saying I truly love the Daily Show. Jon Stewart cracks me up, and together with MSN (my homepage) and Facebook, he’s one of my three main sources of political news. His focus, of course, is politics not science, and that’s why although his satire is reliably hilarious, when it comes to scientific & public health controversies he tends to shoot a little wide of the mark.
Take, for example, the chemical azodicarbonamide. Recently Stewart decried its presence in Subway sandwich bread because it’s also found in yoga mats, which to him proved it was dangerous — no more needed to be said. But wait a minute. Gypsum is both a food additive and an industrial chemical used to make drywall; does Stewart think it should be banned too? While we’re at it why not ban salt? they use that to make chlorine gas through electrolysis, dontcha know. Now there’s some scary stuff.
As it happens, I agree removing azodicarbonamide from bread is probably a good idea because it’s not really necessary and if a food additive is both questionable and not really necessary, why not take it out? makes life simpler. On the other hand, however, although I think taking it out is a no-brainer, at the same time I have to point out the evidence to show azodicarbonamide is dangerous at 45 parts per million (the FDA-mandated limit) isn’t exactly overwhelming. So why did Subway decide to remove it now, and how did Jon Stewart hear about it? It turns out their decision was prompted by a petition circulated by a food blogger I’d never heard of called The Food Babe (and yes, Food Babe is what she calls herself).
The wonderful thing about the Internet is that it makes it so easy to access information — and of course that’s the downside to the Internet too. It only takes a click and a few spare minutes to satisfy your curiosity, with the result that you end up learning about all kinds of things you didn’t really need to know, like Katie Perry’s love life and which celebrities have cool tattoos. This is especially true if you’re at work surfing the internet on your lunch. That was how I ended up reading through a few posts from The Food Babe’s blog, which claims four million followers all told. In retrospect I wish I’d kept reading about Katie Perry’s love life instead.
Food Babe is on a mission to find out what’s in your food. That’s commendable in itself and some of what she’s doing is interesting. The problem is she blends information with misinformation all over the place. Take, for example, this article about What’s In Your Tea. Food Babe points out that some tea bags are made of plastic like nylon or polylactic acid (a corn-based biodegradable plastic) while others are made from paper, and the paper-based bags are treated with polyamide-epichlorohydrin resins. So what the hell is that? and why would anybody put it in a teabag? Well, let me explain.
The 3D structure of epichlorhydrin is like this:
Think back to my last post about the West Virginia chemical spill. Remember that a carbon atom with four bonds wants to have its four bonds arranged so it’s at the center of a tetrahedron. You can rationalize this by remembering that bonds are pairs of shared electrons and electrons repel each other so bonds want to be as far away from each other as they can*.
Look at the two carbons(black) in that three-membered ring or triangle up at the top. Because they’re part of a triangular three-membered ring their bonds to the oxygen atom(red) are forced into a shape they’d rather not assume and are strained. The strain makes those bonds easier to break in the same way bending a piece of plastic out of shape makes it easier to snap.
That might not matter so much if it weren’t for the oxygen atom. Remember that as you go towards the upper right-hand corner of the periodic table elements get more selfish about how they share electrons. Oxygen is much more selfish than carbon so the two carbons in this ring are electron-poor while the oxygen is electron-rich. The combination of uneven electron density together with the strained bonds means this two-carbon one-oxygen triangle is very reactive. This type of ring is called an epoxide.
Almost any time you see an epoxide you can bet the carbon atoms in it want to react with things that are electron-rich, like nitrogen atoms in DNA. The exception is if the epoxide ring has lots of bulky carbon chains on it that block electron-rich stuff from reacting with it. With an unencumbered epoxide ring like this one, however, it’s pretty reactive. That’s why many epoxides are highly toxic and/or carcinogenic. Take this one for example:
There are some molds that grow on peanuts and produce chemicals called aflatoxins. When your liver gets ahold of aflatoxin it modifies it to make the compound you see above. Notice how it contains an epoxide ring? That epoxide ring can react with DNA, and that’s why aflatoxins are carcinogens. They’re entirely natural carcinogens, by the way; they’re made by molds found in nature, and peanut butter may contain aflatoxins at trace concentrations because it’s damn near impossible to remove them completely, although the amount peanut butter can contain is strictly regulated by FDA. Once again, “Mother Nature” turns out to be less friendly than she appears. Why this crazy mold wants to give us cancer nobody knows. But anyhow. Let’s get back to epichlorohydrin.
Notice the green chlorine atom down at the corner. Chlorine is much more electron-hungry than carbon. It’s also much bigger than carbon because it’s a whole row further down in the periodic table. When you have a carbon that has all single bonds attached to a chlorine, the bond between them is long and weak, and since the chlorine is hogging the electrons they share, that carbon is tempted to react with anything really electron-rich, kicking the chlorine atom out of the molecule in the process.
Based on its structure, you would predict that epichlorohydrin should be highly toxic and carcinogenic because the unencumbered epoxide ring and the chlorine-on-a-single-bonded-carbon are pretty reactive in ways we don’t like. And you’d be right. Lab tests have shown it’s exactly that.
So what kind of moron would put epichlorohydrin anywhere near a tea bag? Well, here’s where the story gets more complicated. Make a tea bag out of a plastic like nylon and it’ll hold together ok in water. Paper on the other hand won’t. If you put paper in water it gets all soggy and falls apart. To make paper water-stable you have to treat it with something. Many manufacturers use a polymer called a polyamide-epichlorohydrin resin, which is made by taking epichlorohydrin and reacting it with a polymer that contains multiple amine or nitrogen groups. The amine groups are electron-rich, so they react with epichlorohydrin molecules and thus become part of a long chain with reactive side chains stuck onto it. Treat paper with the resulting polymer and you make it more water-stable**.
If the epichlorohydrin is used up in the reaction, then who cares? Trouble is any remaining epichlorohydrin can react with water to form this critter:
The epoxide ring in epichlorohydrin is so reactive it reacts with water molecules. This end product is called 3-MCPD and since it still contains a chlorine atom connected to an all-single-bonds carbon, it can react with electron-rich stuff; your body metabolizes it in part by knocking off the chlorine and converting some of it back to an epoxide called glycidol which (like most epoxides) is bad news. Based on the structure you’d predict 3-MCPD is carcinogenic, and the State of California says based on available evidence they’re pretty sure it is carcinogenic like you’d expect. So I assume Food Babe doesn’t like epichlorohydrin in tea bag production because you get trace levels of 3-MCPD at the other end, and that residual 3-MCPD probably ends up in your tea. That’s a fair concern and definitely worthy of investigation.
Food Babe didn’t go into any of this, just basically said tea bag manufacturers use epichloroydrin which is dangerous so that’s bad, but hey, same difference. It’s cool she brought this up because it’s something you probably don’t think about a lot unless you’re into chemistry or something. (How come a paper tea bag holds together when paper usually falls apart in water, hmmmm?) She also raises some legitimate concerns about whether pesticide residues are found on certain tea brands and if so at what levels. Which is also stuff worth thinking about.
Now I don’t drink a lot of tea. But if I did and I were looking to avoid this 3-MCPD issue, I would say that teabags made from polylactic acid would be a better way to go. I’m not a big fan of nylon because it ends up in landfills and isn’t very biodegradable; polylactic acid is made from corn and is much easier for microbes to break down, so as an environmentalist that makes me happy. Food Babe, however, doesn’t like polylactic acid because it’s made from genetically modified corn, which is (she says) unnatural. That’s where she and I part company. If you’ve read any of my past posts about GMOs and “natural=good” you’ll know why. And her article just goes downhill from there.
Food Babe quotes Dr. Mercola, IMHO one of the quackiest rogue doctors on the web, about the safety of nylon in teabags. For starters, if you’re using Dr. Mercola as a source, you need a factchecker in the house. Mercola is a dude who makes money by arguing that vaccines and traditional medicine are harmful and that his “natural supplements” are a better way to go. The FDA had to send the guy warning letters because his website claimed his infrared camera was a “safe cancer screening tool” that could “detect hidden inflammation“. This doctor-turned-supplement-guru is such a joke he has his very own page on the quack-tracking website Quackwatch. And leaving aside the source, her argument as to why nylon is bad is ill-informed:
“While the plastic itself won’t melt in your tea, the glass transition temperature could potentially leak out harmful phthalates if there are such things in your tea.”
You don’t use phthalates to make nylon. Maybe Food Babe should find out what nylon actually is before she starts telling us why it’s such a terrible thing. Actually nylon is reasonably harmless stuff, Food Babe to the contrary. My only beef with it would be that like most plastics it’s not terribly biodegradable. Given that most teabags probably end up in landfills that’s kind of a problem.
And then there’s this, which is so hopeless it made me want to stop reading:
“Furthermore, a majority of Teavana teas contain added flavor – specifically “artificial flavoring”. If their tea is so high-end, why would they be adding ingredients produced by fractional distillation and chemical manipulation of various chemicals like crude oil or coal tar? Coal tar in my tea? No, thanks.”
Crude oil and coal tar are sources of hydrocarbons you use as building blocks. In the course of those reactions those building blocks are converted into new molecules with entirely different properties from the original building blocks. Assuming that something is bad because it was made from hydrocarbons that came from crude oil is ridiculous. You might as well argue the water you drink is bad because it was dinosaur urine once upon a time. Well, yeah, sure, but it’s come a long way since then, you know.
The remarkable things that Food Babe believes are so numerous I don’t have time to go through most of them. Here’s a few examples that really bothered me. Food Babe believes that propylene glycol is toxic because it’s found in antifreeze. What she really means is ethylene glycol, which has two carbons compared to propylene glycol’s three — and believe it or not that makes a huge difference. Food Babe is also not a fan of potassium sorbate because it’s a preservative. Now there are preservatives I don’t like, but I have nothing against potassium sorbate. Here’s the structure:
Any time you see that COO- group with a straight chain of hydrocarbons attached to it, you’re looking at a fatty acid. If that fatty acid contains double bonds it’s unsaturated, while if it’s all single bonds it’s saturated. So potassium sorbate is an unsaturated fatty acid. Your body handles it the same way it would any other fat: fuel. It’s fat. It’s something you can burn. So potassium sorbate is relatively harmless from your point of view; your body will just take it and burn it for fuel. It makes mold grow more slowly and that’s why we use it as a preservative. Why Food Babe doesn’t like it I have no idea.
And this is far from the worst of it, because as it turns out Food Babe doesn’t like the flu shot, either. Now there are things not to like about the flu shot. The flu shot only protects against a few strains, the ones CDC thinks are most likely to be running around in a given year, and sometimes they get that wrong because the virus is so freaking unpredictable. You could argue that if you’re a young healthy adult like Food Babe, you’re not worried about dying from flu, so you’re not going to take a shot that may or may not protect you from a disease that is unlikely to kill you anyway. And that would be a fair argument to make. Before you doctors out there start giving me a hard time, however, please bear in mind, I’m not saying I agree or disagree, I’m saying that’s a fair argument we can debate. But that’s not why Food Babe doesn’t like the flu shot. Food Babe doesn’t like it because it contains toxic chemicals like formaldehyde and aluminum salts.
Never mind that Food Babe’s blood naturally contains many times more formaldehyde than you’ll find in a vaccine, and never mind she’s exposed to aluminum in nearly everything she eats because aluminum is found in dirt and many plants are reasonably good at taking up small amounts of it. Food Babe doesn’t know or doesn’t care. She just knows the flu shot isn’t natural. Presumably Food Babe uses cars, condoms and computers just like me, and presumably she knows those aren’t natural too. But somehow the irony is lost on her.
So this is why I should have kept reading about Katie Perry’s fascinating love life instead of googling Subway and azodicarbonamide, which led me by a few short clicks to Food Babe’s blog. Food Babe’s blog is frustrating to read because she’s writing about a subject with so much potential and yet so much of it is wrong. It really would be fascinating to discuss in detail all the stuff that’s in your food. There’s a lot of things in there you don’t know or think about. Take this business with the epichlorohydrin-polyamide resins; or the natural carcinogens produced by molds on moldy peanuts. Those are things you probably didn’t know, right? It would be very cool for someone to go out there and blog about all this kind of stuff; take a close look at what’s really in your food and how it’s made. It would be a real eye-opener. Unfortunately, that’s not what Food Babe is doing.
She’s just feeding her four million followers more of the same old Mother Nature Knows Best crap — if it’s not natural, don’t buy it. And that’s why her blog is such a seamless blend of interesting facts and mindless ignorance. That’s why she can simultaneously slam polyamide-epichlorohydrin in tea bag manufacture (which might be something worth criticizing) and the flu vaccine (which has been extensively tested for safety and is certainly not).
There’s something I was told when I was a kid that I’ve always found true: life is complicated, and the closer you look at it the messier it gets. There are no easy answers. This is true of science just as it is of politics or relationships or really anything else. If you meet someone who claims they have a simple answer that solves everything, they’re probably trying to sell you something. Unfortunately we humans are attracted to easy answers and simple solutions, which is how politicians and self-help gurus and snake oil salesmen make a living. Your life would be great if you’d learn these simple laws of success. Elect me as president and the Change will begin. Eat all-natural foods and you’ll be healthy forever. It sounds nice. If only it were true…
*This is how the valence-shell electron pair repulsion or VSEPR model explains the tetrahedral shape. VSEPR is nice because it’s simple and enables you to quickly figure out a molecule’s shape in your head. For the chemistry undergrads out there, however, remember that VSEPR is just a nice little qualitative predictive tool and nothing more…quantum chemistry provides a more accurate explanation for why a molecule has the shape it does. The closer you look the more complicated it gets as usual.
**There is still some debate over what’s going on here — are the side chains in the polymer reacting with hydroxyls on cellulose or are the polymers becoming cross-linked and wrapping around cellulose fibers to hold them together? Either way, it works.