Many people who read this blog are chemists. Those who aren't often come from other branch of the sciences, and if they don't, it's safe to say that they're at least interested in science (or they probably don't hang around very long!) It's difficult, if you live and work in this sort of environment, to keep in mind what people are willing to believe about chemistry.
But that's what we have the internet for. Many science-oriented bloggers have taken on what's been called "chemophobia", and they've done some great work tearing into some some really uninformed stuff out there. But nonsense does not obey any conservation law. It keeps on coming. It's always been in long supply, and it looks like it always will be.
That doesn't mean that we just have to sit back and let it wash over us, though. I've been sent this link in the last few days, a popular item on BuzzFeed with the BuzzFeedy headline of "Eight Foods That We Eat in The US That Are Banned in Other Countries". When I saw that title, I found it unpromising. In a world that eats everything that can't get away fast enough, what possible foods could we have all to ourselves here in the States? A quick glance was enough: we're not talking about foods here - we're talking about (brace yourselves) chemicals.
This piece really is an education. Not about food, or about chemistry - on the contrary, reading it for those purposes will make you noticeably less intelligent than you were before, and consider that a fair warning. The educational part is in the "What a fool believes" category. Make no mistake: on the evidence of this article, its author is indeed a fool, and has apparently never yet met a claim about chemicals or nutrition that was too idiotic to swallow. If BuzzFeed's statistics are to be believed (good question, there), a million views have already accumulated to this crap. Someone who knows some chemistry needs to make a start at pointing out the serial stupidities in it, and this time, I'm going to answer the call. So here goes, in order.
Number One: Artificial Dyes. Here's what the article has to say about 'em:
Artificial dyes are made from chemicals derived from PETROLEUM, which is also used to make gasoline, diesel fuel, asphalt, and TAR! Artificial dyes have been linked to brain cancer, nerve-cell deterioration, and hyperactivity, just to name a few.
Emphasis is in the original, of course. How could it not lapse into all-caps? In the pre-internet days, this sort of thing was written in green ink all around the margins of crumpled shutoff notices from the power company, but these days we have to make do with HTML. Let's take this one a sentence at a time.
It is true, in fact, that many artificial dyes are made from chemicals derived from petroleum. That, folks, is because everything (edible or not) is made out of chemicals, and an awful lot of man-made chemicals are derived from petroleum. It's one of the major chemical feedstocks of the world. So why stop at artificial dyes? The ink on the flyer from the natural-foods co-op is made from chemicals derived from petroleum. The wax coating the paper wrapped around that really good croissant at that little bakery you know about is derived from petroleum.
Now, it's true that more things you don't eat can be traced back to petroleum feedstocks than can things you do eat. That's because it's almost always cheaper to grow stuff than to synthesize it. Synthesized compounds, when they're used in food, are often things that are effective in small amounts, because they're so expensive. And so it is with artificial dyes - well, outside of red velvet cake, I guess. People see the bright colors in cake icing and sugary cereals and figure that the stuff must be glopped on like paint, but paint doesn't have very much dye or pigment in it, either (watch them mix it up down at the hardware store sometime).
And as for artificial colors causing "brain cancer, nerve-cell deterioration, and hyperactivity", well, these assertions range from "unproven" all the way down to "bullshit". Hyperactivity sensitivities to food dyes are an active area of research, but after decades of work, the situation is still unclear. And brain cancer? This seems to go back to studies in the 1980s with Blue #2, where rats were fed the dye over a long period in much larger concentrations (up to 2% of their total food intake) than even the most dedicated junk-food eater could encounter. Gliomas were seen in the male rats, but with no dose-response, and at levels consistent with historical controls in the particular rat strain. No one has ever been able to find any real-world connection. Note that glioma rates increased in the 1970s and 1980s as diagnostic imaging improved, but have fallen steadily since then. The age-adjusted incidence rates of almost all forms of cancer are falling, by the way, not that you'd know that from most of the coverage on the subject.
Number Two: Olestra
This, of course, is Proctor & Gamble's attempted non-calorific fat substitute. I'm not going to spend much time on this, because little or nothing is actually made with it any more. Olestra was a major flop for P&G the only things (as far as I can tell) that still contain it are some fat-free potato chips. It does indeed interfere with the absorption of fat-soluble vitamins, but potato chips are not a very good source of vitamins to start with. And vitamin absorption can be messed with by all kinds of things, including other vitamins (folic acid supplements can interfere with B12 absorption, just to pick one). But I can agree with the plan of not eating the stuff: I think that if you're going to eat potato chips, eat a reasonable amount of the real ones.
Number Three: Brominated Vegetable Oil. Here's the article's take on it:
Bromine is a chemical used to stop CARPETS FROM CATCHING ON FIRE, so you can see why drinking it may not be the best idea. BVO is linked to major organ system damage, birth defects, growth problems, schizophrenia, and hearing loss.
Again with the caps. Now, if the author had known any chemistry, this would have looked a lot more impressive. Bromine isn't just used to keep carpets from catching on fire - bromine is a hideously toxic substance that will scar you with permanent chemical burns and whose vapors will destroy your lungs. Drinking bromine is not just a bad idea; drinking bromine is guaranteed agonizing death. There, see what a little knowledge will do for you?
But you know something? You can say the same thing for chlorine. After all, it's right next to bromine in the same column of the periodic table. And its use in World War I as a battlefield gas should be testimony enough. (They tried bromine, too, never fear). But chlorine is also the major part, by weight, of table salt. So which is it? Toxic death gas or universal table seasoning?
Knowledge again. It's both. Elemental chlorine (and elemental bromine) are very different things than their ions (chloride and bromide), and both of those are very different things again when either one is bonded to a carbon atom. That's chemistry for you in a nutshell, knowing these differences and understanding why they happen and how to use them.
Now that we've detoured around that mess, on to brominated vegetable oil. It's found in citrus-flavored sodas and sports drinks, at about 8 parts per million. The BuzzFeed article claims that it's linked to "major organ system damage, birth defects, growth problems, schizophrenia, and hearing loss", and sends readers to this WebMD article. But if you go there, you'll find that the only medical problems known from BVO come from two cases of people who had been consuming, over a long period, 4 to 8 liters of BVO-containing soda per day, and did indeed have reactions to all the excess bromine-containing compounds in their system. At 8 ppm, it's not easy to get to that point, but a determined lunatic will overcome such obstacles. Overall, drinking several liters of Mountain Dew per day is probably a bad idea, and not just because of the BVO content.
Number Four: Potassium Bromate. The article helpfully tells us this is "Derived from the same harmful chemical as brominated vegetable oil". But here we are again: bromate is different from bromide is different than bromine, and so on. If we're going to play the "made from the same atoms" game, well, strychnine and heroin are derived from the same harmful chemicals as the essential amino acids and B vitamins. Those harmful chemicals, in case you're wondering, are carbon, hydrogen, oxygen, and nitrogen. And to get into the BuzzFeed spirit of the thing, maybe I should mention that carbon is found in every single poisonous plant on earth, hydrogen is the harmful chemical that blew up the Hindenburg, oxygen is responsible for every death by fire around the world, and nitrogen will asphyxiate you if you try to breath it (and is a key component of all military explosives). There, that wasn't hard - as Samuel Johnson said, a man might write such stuff forever, if only he would give over his mind to it.
Now, back to potassium bromate. The article says, "Only problem is, it’s linked to kidney damage, cancer, and nervous system damage". And you'll probably fall over when I say this, but that statement is largely correct. Sort of. But let's look at "linked to", because that's an important phrase here.
Potassium bromate was found (in a two-year rat study) to have a variety of bad effects. This occurred at the two highest doses, and the lowest observed adverse effect level (LOAEL) was 6.1 mg of bromate per kilo body weight per day. It's worth noting that a study in male mice took them up to nearly ten times that amount, though, with little or no effect, which gives you some idea of how hard it is to be a toxicologist. Whether humans are more like mice or more like rats in this situation is unknown.
I'm not going to do the whole allometric scaling thing here, because no matter how you do it, the numbers come out crazy. Bromate is used in some (but not all) bread flour at 15 to 30 parts per million, and if the bread is actually baked properly, there's none left in the finished product. But for illustration, let's have someone eating uncooked bread dough at the highest level, just to get the full bromate experience. A 75-kilo human (and many of us are more than that) would have to take in 457 mg of bromate per day to get to the first adverse level seen in rats, which would be. . .15 kilos (about 33 pounds) of bread dough per day, a level I can safely say is unlikely to be reached. Hell, eating 33 pounds of anything isn't going to work out, much as my fourteen-year-old son tries to prove me wrong. You'd need to keep that up for decades, too, since that two year study represents a significant amount of a rat's lifespan.
Number Five: Azodicarbonamide. This is another bread flour additive. According to the article, "Used to bleach both flour and FOAMED PLASTIC (yoga mats and the soles of sneakers), azodicarbonamide has been known to induce asthma".
Let's clear this one up quickly: azodicarbonamide is indeed used in bread dough, and allowed up the 45 parts per million. It is not stable to heat, though, and it falls apart quickly to another compound, biurea, on baking. It not used to "bleach foamed plastic", though. Actually, in higher concentrations, it's used to foam foamed plastics. I realize that this doesn't sound much better, but the conditions inside hot plastic, you will be glad to hear, are quite different from those inside warm bread dough. In that environment, azodicarbonamide doesn't react to make birurea - it turns into several gaseous products, which are what blow up the bubbles of the foam. This is not its purpose in bread dough - that's carbon dioxide from the yeast (or baking powder) that's doing the inflating there, and 45 parts per million would not inflate much of anything.
How about the asthma, though? If you look at the toxicology of azodicarbonamide, you find that "Azodicarbonamide is of low acute toxicity, but repeated or prolonged contact may cause asthma and skin sensitization." That, one should note, is for the pure chemical, not 45 parts per million in uncooked flour (much less zero parts per million in the final product). If you're handling drums of the stuff at the plastics plant, you should be wearing protective gear. If you're eating a roll, no.
Number Six: BHA and BHT. We're on the home stretch now, and this one is a two-fer. BHA and BHT are butylated hydroxyanisole and butylate hydroxytoluene, and according to the article, they are "known to cause cancer in rats. And we’re next!"
Well, of course we are! Whatever you say! But the cancer is taking its time. These compounds have been added to cereals, etc., for decades now, while the incidence rates of cancer have been going down. And what BuzzFeed doesn't mention is that while some studies have shown an increase in cancer in rodent models with these compounds, others have shown a measurable decrease. Both of these compounds are efficient free radical scavengers, and have actually been used in animal studies that attempt to unravel the effects of free radicals on aging and metabolism. Animal studies notwithstanding, attempts to correlate human exposure to these compounds with any types of cancer have always come up negative. Contrary to what the BuzzFeed article says, by the way, BHT is indeed approved by the EU.
Weirdly, you can buy BHT in some health food stores, where anti-aging and anti-viral claims are made for it. How does a health food store sell butylated hydroxytoluene with a straight face? Well, it's also known to be produced by plankton, so you can always refer to it as a natural product, if that makes you feel better. That doesn't do much for me - as an organic chemist, I know that the compounds found in plankton range from essential components of the human diet all the way down to some of the most toxic molecules found in nature.
Number Seven: Synthetic Growth Hormones. These are the ones given to cattle, not the ones athletes give to themselves. The article says that they can "give humans breast, colon, and prostate cancer", which, given what's actually known about these substances, is a wildly irresponsible claim.
The article sends you to a perfectly reasonable site at the American Cancer Society, which is the sort of link that might make a BuzzFeed reader think that it must then be about, well, what kinds of cancer these things give you. But have a look. What you find is (first off) this is not an issue for eating beef. Bovine growth hormone (BGH) is given to dairy cattle to increase milk production. OK, so what about drinking milk?
Here you go: for one, BGH levels in the milk of treated cows are not higher than in untreated ones. Secondly, BGH is not active as a growth hormone in humans - it's selective for the cow receptor, not the human one. The controversy in this area comes from the way that growth hormone treatment in cows tends to increase levels of another hormone, IGF-1, in the milk. That increase still seems to be within the natural range of variability for IGF-1 in regular cows, but there is a slight change.
The links between IGF-1 and cancer have indeed been the subject of a lot of work. Higher levels of circulating IGF-1 in the bloodstream have (in some studies) been linked to increased risk of cancer, but I should add that other studies have failed to find this effect, so it's still unclear what's going on. I can also add, from my own experiences in drug discovery, that all of the multiple attempts to treat cancer by blocking IGF-1 signaling have been complete failures, and that might also cause one to question the overall linkage a bit.
But does drinking milk from BGH-treated cows increase the levels of circulating IGF-1 at all? No head-to-head study has been run, but adults who drink milk in general seem to have slightly higher levels. The same effect, though, was seen in people who drink soymilk, which (needless to say) does not have recombinant cow hormones in it. No one knows to what extent ingested IGF-1 might be absorbed into the bloodstream - you'd expect it to be digested like any other protein, but exceptions are known.
But look at the numbers. According to that ACA web summary, even if the protein were not degraded at all, and if it were completely absorbed (both of which are extremely unrealistic top-of-the-range assumptions), and even if the person drinking it were an infant, and taking in 1.6 quarts a day of BGH-derived cow milk with the maximum elevated levels of IGF-1 that have been seen, the milk would still contribute less than 1% of the IGF-1 in the bloodstream compared to what's being made in the human body naturally.
Number Eight, Arsenic. Arsenic? It seems like an unlikely food additive, but the article says "Used as chicken feed to make meat appear pinker and fresher, arsenic is POISON, which will kill you if you ingest enough."
Ay. I think that first off, we should make clear that arsenic is not "used as chicken feed". That brings to mind someone pitching powdered arsenic out for the hens, and that's not part of any long-term chicken-farming plan. If you go to the very NPR link that the BuzzFeed article offers, you find that a compound called roxarsone is added to chicken feed to keep down Coccidia parasites in the gut. It is not just added for some cosmetic reason, as the silly wording above would have you believe.
In 2011, a study found that chicken meat with detectable levels of roxarsone had 2.3 parts per billion (note the "b") of inorganic arsenic, which is the kind that is truly toxic. Chicken meat with no detectable roxarsone had 0.8 ppb inorganic arsenic, threefold less, and the correlation seems to be real. (Half of the factory-raised chickens sampled had detectable roxarsone, by the way). This led to the compound being (voluntarily) withdrawn from the market, under the assumption that this is an avoidable exposure to arsenic that could be eliminated.
And so it is. There are other (non-arsenic) compounds that can be given to keep parasite infestations down in poultry, although they're not as effective, and they'll probably show up on the next edition of lists like this one. But let's get things on scale: it's worth comparing these arsenic levels to those found in other foods. White rice, for example comes in at about 100 parts per billion of inorganic arsenic (and brown rice at 170 ppb). These, by the way, are all-natural arsenic levels, produced by the plant's own uptake from the soil. But even those amounts are not expected to pose a human health risk (says both the FDA and Canadian authorities), so the fifty-fold lower concentrations in chicken would, one thinks, be even less to worry about. If you're having chicken and rice and you want to worry about arsenic, worry about the rice.
This brings me to the grand
wrap-up, and some of the language in that last item is a good starting point for it. I'm talking about the "POISON, which will kill you if you ingest enough" part. This whole article is soaking in several assumptions about food, about chemistry, and about toxicology, and that's one of the big ones. In my experience, people who write things like this have divided the world into two categories: wholesome, natural, healthy stuff and toxic chemical poisons. But this is grievously simple-minded. As I've emphasized in passing above, there are plenty of natural substances, made by healthy creatures in beautiful, unpolluted environments, that will nonetheless kill you in agony. Plants, fungi, bacteria, and animals produce poisons, wide varieties of intricate poisons, and they're not doing it for fun.
And on the other side of the imaginary fence, there are plenty of man-made substances that really won't do much of anything to people at all. You cannot assume anything about the effects of a chemical compound based on whether it came from a lovely rainforest orchid or out of a crusty Erlenmeyer flask. The world is not set up that way. Here's a corollary to this: if I isolate a beneficial chemical compound from some natural source (vitamin C from oranges, for example, although sauerkraut would be a good source, too), that molecule is identical to a copy of it I make in my lab. There is no essence, no vital spirit. A compound is what it is, no matter where it came from.
Another assumption that seems common to this mindset is that when something is poisonous at some concentration, it is therefore poisonous at all concentrations. It has some poisonous character to it that cannot be expunged nor diluted. This, though, is more often false than true. Paracelsus was right: the dose makes the poison. You can illustrate that in both directions: a beneficial substance, taken to excess, can kill you. A poisonous one, taken in very small amounts, can be harmless. And you have cases like selenium, which is simultaneously an essential trace element in the human diet and an inarguable poison. It depends on the dose.
Finally, I want to return to something I was saying way back at the beginning of this piece. The author of the BuzzFeed article knows painfully little about chemistry and biology. But that apparently wasn't a barrier: righteous conviction (and the worldview mentioned in the above three paragraphs) are enough, right? Wrong. Ten minutes of unbiased reading would have served to poke holes all through most of the article's main points. I've spent more than ten minutes (as you can probably tell), and there's hardly one stone left standing on another. As a scientist, I find sloppiness at this level not only stupid, not only time-wasting, but downright offensive. Couldn't anyone be bothered to look anything up? There are facts in this world, you know. Learn a few.