Chlorinated sugar…?

I was flicking through the rather marvellous webcomic, Abstruse Goose, recently, when I happened upon this particular comic (click the panel for the full version). Wait, what? Chlorinated sugar? This piqued my curiosity somewhat, so cat-like as ever*, I decided to investigate further. It turns out that, as they say, many a true word is spoken in jest.

Make no mistake. The artificial sweetener sucralose, more popularly known as Splenda®, is precisely that. Chlorinated sugar. It’s also known as 1′,4,6′-Trichlorosucrose, E955 or (deep breath!) 1,6-dichloro-1, 6-dideoxy-β-D-fructofuranosyl-4-chloro-4-deoxy-α-D-galactopyranoside. Containing chlorine atoms covalently bonded to carbon atoms, it’s an organochloride compound (also known as a chlorocarbon). This makes me raise a slightly skeptical eyebrow. Now, I have nothing against chlorine, but the releasing of chlorocarbons into the environment on a large scale? That makes me a bit uneasy.

I’ll make no secret of the fact that I detest artificial sweeteners. As opposed to the good old fashioned sugar that our digestive systems have spent hundreds of millions of years evolving to digest efficiently, many people seem to favour fabricated chemicals which apparently taste “sweeter”. As far as I’m concerned, they spoil the taste of things. Since when did “no added sugar” come to mean “icky artificial sweeteners added instead of sugar”? Couldn’t they just – you know – not add any sugar? But enough of my ranting. I have a little more than just personal opinion to go on here.

The two molecules to the left are sucrose and sucralose. A disaccharide, sucrose is made from one molecule of fructose and one of glucose. It’s the dominant type of sugar in sugar cane and sugar beet. Just plain ordinary table sugar. The same kind found across the world.

Sucralose, as the Splenda® people rightly claim, is “made from sugar”. Just chop off a couple of hydroxy groups and swap them with chlorine (which is, admittedly, easier said than chemically reacted). In fairness, it is perhaps the least awful tasting of the artificial sweeteners still available**. In fact it seems to be steadily replacing aspartame, which is arguably a good thing.

So what’s the big deal? What’s my problem with chlorinated sugar? The trouble with organochlorides is that, while not necessarily toxic, they’re notoriously stable. A good example would be a certain famous chlorocarbon.

Now let me make it quite clear — I’m not comparing sucralose to DDT. They’re very different chemicals, with different uses, reactivities, stabilities and so forth. The point to this paragraph is more to highlight precisely how stable large chlorocarbons can be, with DDT being a prominent example. DDT was used widely as a pesticide during 1940s and 1950s, due to it being extremely toxic to invertebrates, but “safe” to vertebrates like people. Except that it isn’t as safe as was once thought. Actually, it’s been linked to diabetes, asthma, neurological problems and birth abnormalities, as well as being a suspected carcinogen. The trouble was that DDT was stupidly stable. It just didn’t break down. As a result, it accumulated in the world’s ecosystems, ravaging coastal invertebrate wildlife and steadily building up in the tissues of predatory animals. Disturbingly, DDT was still found in human blood samples as recently as 2005 and is regularly found in food samples tested by the FDA.

Sucralose is similarly stable (albeit less so), and when it does break down, it doesn’t break into anything harmful. No other sweetener holds the accolade of being considered “safe” by the Center for Science in the Public Interest. The trouble is that it’s low calorie because it isn’t really absorbed by the human body. Most will pass straight through you, with only around 4 – 12% actually being metabolised. Indeed, the Swedish Environmental Protection Agency has cautioned about potential rising levels of the stuff in wastewater. Water treatment plants were shown to have little effect on sucralose, with it being present at moderate levels in effluent water.

Of course, as I said above, not all organochlorides are toxic as such. I’m certainly not saying that Splenda® is evil. Quite the contrary, it’s been found by repeated tests to be perfectly safe at the kind of levels involved in daily food consuption***. Though, knowing how chlorocarbons have caused environmental issues in the past, I can’t help but hope that the scientists involved in manufacturing the stuff know exactly what they’re unleashing on the world.

Personally, I’ll be sticking to natural sugars. If nothing else, in my humble opinion, they taste nicer.

*On that note, I don’t take too well to being herded either.

**I say ‘still available’. Several have been taken off the market after being found to break down into toxic fragments. Which is still better than in ancient times — the less said about sugar of lead the better!

***It’s worth noting though, that not much data exists regarding higher levels of sucralose, and those data that do exist don’t look good. But then, almost anything is toxic at a sufficiently high dosage.

About Invader Xan

Molecular astrophysicist, usually found writing frenziedly, staring at the sky, or drinking mojitos.
This entry was posted in chemistry, Imported from Livejournal, molecular gastronomy and tagged . Bookmark the permalink.

22 Responses to Chlorinated sugar…?

  1. Laurence Grainey says:

    Products that are labeled zero calories are not that promising. It’s true. There are no calories in them but to make them taste as good as they are, substitutes are added. Artificial sweeteners that come with side effects are included in the ingredients. They have to be, to redeem the flavor. Otherwise, the products will end up too awful to be a delight.You’d think you’re in the right track with artificial sweeteners. With no calories, you can say goodbye to some extra pounds in your system. You feel as if you’re doing alright. Well, you’re not. Truth be told, if you intend on losing weight through these empty calories, you are kidding yourself. Not only do they not have any dieting advantage, they, also, puncture your body with other effects.’

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  2. Anonymous says:

    that would be thalidomide (the morning sickness pill that caused a syndrome now known as thalidomide baby)

  3. invaderxan says:

    Oh wow. So only one enantiomer was actually teratogenic? Now that, I didn’t know — thank you!

  4. nedu says:

    Also, thalidomide was manufactured and distributed as a racemic mixture. One enantiomer did not contribute to the positive effects of the drug and acted as a teratogen. This didn’t make the “good” enantiomer entirely safe, since it could be converted to the teratogenic enantiomer in vivo. However, the incident did make people aware that racemic mixtures might not always be the most effective treatments and led to the production of drugs that consisted of only one enantiomer.

  5. invaderxan says:

    Everyone loves the food science. :)
    Rest assured, I have another post in mind — though I’m not certain about a recipe. I’ll have to see what I can dream up…
    And TBH, I’m really not sure about fluorinated sugar. But as someone else mentioned it to me too (on Twitter), I might just have to look into it. I believe the fluoride normally used in water supplies is hexafluorosilicic acid (H2SiF6), with sodium fluoride (NaF) being used previously — though I really don’t know much about organofluorides. I do know that fluoride ions can be highly toxic though (part of the reason hydrofluoric acid is so dangerous!). If I have the time, I’ll look into it. It interests me too! Watch this space… ;)
    And don’t apologise. It’s hardly spamming when it’s an enjoyable discussion like this one!

  6. orthoflame says:

    Only if you post another food science+recipe post. I’m itching to read another one! :D But yeah, I’ll post it whenever I get the chance.
    BTW, I wanted to ask you something. What would you think of fluorinated sugar? They say fluorine is good for your teeth and has some other positive health benefits – could that translate into a sugar sweetener? As in, do you think it’d be as ‘harmless’ as our lovely sucralose, or would that be a different case on its own?
    Gah, sorry for spamming your entry with so many comments! This is really an interesting article, and I’ve always been a bit curious about Splenda.

  7. invaderxan says:

    Care to share the recipe…? ;)

  8. orthoflame says:

    Yes, that’s the drug! I also think scientists have wised-up with drug testing after thalidomide, but sometimes the longer-term effects of chemicals aren’t quite as apparent during the study. I’m staying relatively optimistic about sucralose, though. I’m also going to avoid the pseudoscience stuff on it (I just wish people knew how bogus this stuff can be).
    Teehee, yes, far-fetched. It’s not like the stuff you get at restaurants. I tried making it relatively low on calories and all that good stuff, not to mention added my own personal touch to it (read: add loads of hot chili oil). It tastes decent enough; a rare case for those of us who are culinary-inept.

  9. invaderxan says:

    Hey, no worries. And yeah, I know people can be sensitive to certain chemicals. Aspartame is one. Actully, caffeine is another…
    I think the drug you’re talking about is thalidomide. That stuff was truly horrific, because while it was prescribed to pregnant women, it was soon found to be a teratogen — a substance which causes horrible birth defects. While I’m fairly sure they test chemicals thoroughly for teratogenic effects since then, it certainly is alarming how often things are taken off the market because they’re revealed to be health hazards.
    …And I’m intrigued. Far-fetched sesame chicken recipe? :)

  10. orthoflame says:

    Heh, my bad. Allergy is probably not the right word. I meant to say it might be a consistent reaction to sucralose in some people. I think some people don’t bode well with other sweeteners like Aspartame – maybe Sucralose has a similar effect, but not quite as prominent at this point in time.
    I also wonder about the long-term effects of Splenda. While it’s overall deemed as safe (and it’s really good for dieters trying to get off of sugar, diabetics, etc.), it might show its not-so-wonderful facet in the future. Kind of like this one drug targeted for pregnant women and morning sickness that seemed great but ended up having very bad side effects (sorry, can’t recall the drug’s name right now).
    From this entry, I actually tried making my far-fetched sesame chicken recipe with real sugar instead of Splenda. Tasted MUCH better, in my humble opinion!
    BTW, I’m a wannabe doctor at this point, so we’re kinda in the same boat. :P

  11. invaderxan says:

    I hadn’t planned to bring up CFCs, TBH, but clearly you’re more knoeledgeable than I am about them. :)
    And as aerosols, I suppose there would be photochemical activity. Things like smogs, or even CFC-esque photolysis in the upper atmosphere. While I’m not sure it would be significant alone, you have to wonder how many uncommon VOCs are in the air, and what their combined effects might be.
    Monday mornings are always a good time to geek out. :P

  12. invaderxan says:

    Some kind of reaction, definitely, but migraines? I’m pretty sure that wouldn’t be an allergy of any kind. Mind you, I’m certainly no doctor!

  13. And… vapour pressure? Is that relevant?
    Well, it is if you are going to consider atmospheric concentrations (since you bring up CFCs, it’s a completely legit concept to think about the vapor pressure, given that many CFCs are, after all gases!), then yes, vapor pressure is important. CFCs have been on my mind as of late due to work — along with relevant CFC vapor pressures.
    I guess the vapor pressure isn’t a problem if you’re talking solely about water-based pollution. But most of the MSDS reports out there cite that it breaks into HCl upon decomposition…. so you could say it has acidifying effects if you combusted enough of the stuff and threw it into the water supply. But how much of the sucralose do you have to have for problems to occur? There are questions I don’t think we have the answers to — at least yet. I don’t know if anyone is doing any studies.
    Also, think about the water cycle too — the sucralose could be moved about into the atmosphere via aerosol processes to react with various VOCs in the atmosphere…. we barely know about a lot of the common VOCs, what about uncommon ones like sucralose?
    I think I just started an interesting train of thought for myself to look into on Monday at work! ;)

  14. orthoflame says:

    Yeah, I don’t know how to interpret the migraine part. The research group was adamant about sucralose being the cause, but even they themselves were confused about the result. Maybe it’s just an allergic reaction of sorts, though not of the same nature (like getting hives)? Hmm…

  15. invaderxan says:

    Don’t get me wrong, I definitely do appreciate that a lot of people like the taste of sweet foods, but don’t want or need the calorie content. In modern society, we simply don’t need as much carbohydrate energy as our manual labouring ancestors once did. That much is perfectly understandable, although how much of that can be blamed on food manufacturers using too much sugar and desensitising us all to is is a matter of open debate.
    As I stress, said chlorinated sugar has been found in tests to be nothing but safe at normal levels of consumption (although my knowlege of the actual trial process is tenuous at best). My real concern though, is that chlorocarbons have a bad track record. For years people will believe them to be harmless until their repurcussions on the environment become evident — CFCs in the atmosphere and DDT in solution being the most notable examples. Perhaps the history of such incidents has left me slightly jaded.
    And… vapour pressure? Is that relevant? I was more considering its effects in solution once in the Earth’s hydrosphere. Given it’s such a large molecule, I’d already pretty much dismissed any gas phase effects as being negligible…

  16. invaderxan says:

    Chemically, it’s certainly rather interesting. It seems to be in something of a class of its own. Not a lot seems to be written about any other chlorosaccharides. Actually, I do have to wonder if other halo-sugars might be the same. ;)
    Yeah, I read something abount Splenda and migraines. Wasn’t quite sure what to make of it TBH. Though it’s certainly a sad fact that a lot of pseudoscience tends to follow anything relating to diet or nutrition. You’re not alone in those particular migraines, believe me!
    And thanks. I’m glad you enjoy reading them. It makes writing them worth doing! :)

  17. Generally, I side with you on preferring sugar based sweetening than non-sugar based sweeteners.
    However, you’re also forgetting that there is a HUGE, and I mean HUGE market for chemicals that sweeten without the metabolic side effect of actually breaking down the chemicals (and thus getting the extra caloric intake). That’s the only reason why I am still able to have some tea on occasion with my copious water consumption — Splenda. I have an aspartame sensitivity (it gives me some nasty headaches), and so most diet carbonated beverages are out in terms of a rare sweet treat. Thus, I can have some Earl Grey or Irish Breakfast tea with a tablespoon of Splenda and actually retain the general flavor of the tea I’m drinking with no nasty headaches or gross aftertastes.
    As much as one might shake a stick at this glorious chlorinated sugar — it’s helping many people like myself lose weight.
    Also, consider that the vapor pressure of solid sucralose is virtually non-existent, so somebody needs to figure out what the vapor pressure of the stuff is while it’s in waste (urine) form to see how much is actually getting out into the environment.

  18. orthoflame says:

    Iodinated sugar FTW!!
    I remember my Ochem professor talking about this in one of our lectures, back when we were talking about carbohydrate chemistry. I always found chlorinated sugar/Splenda an interesting concept, especially since it doesn’t seem to share the same side-effects/dangers as other organochlorides.
    Oh, and speaking of Splenda’s ‘safeness,’ I remember reading a case study about a woman who would get intense migraines from consumption of sucralose. The research group never really got to a conclusion on what was causing the migraines, but they did find that it was indeed sucralose that was causing the problem. While interesting, I think stuff like this gives rise to pseudoscience, which gives ME migraines. Ugh…
    I think I’ve mentioned this before, but I like how informative yet approachable your articles are. Makes me look forward for the next one(s). :) Thanks for sharing this!

  19. invaderxan says:

    Haha! Totally! :P

  20. invaderxan says:

    Very true. A lot more polarity and a complete lack of aromaticity makes for a much less stable compound. All the same, it’s notable how it seems to be quite resistant to both human metabolism and water treatment.
    And actually, I didn’t know that, thanks. Molecular biology is something of a blind spot of mine. From an evolutionary perspective, that all certainly seems to make sense. Presumably then, fructose would be the sweetest natural sugar because it’s small enough to bind better to those sweetness receptors…?
    As an aside, what do you make of this stuff?

  21. madsophia says:

    rad. I can’t wait to tell someone they are drinking chlorinated sugar!

  22. 6_bleen_7 says:

    It’s been quite a while since organic chemistry, but it seems to me that the glycoside bond, and the hemiacetal and hemiketal groups (alternatively, aldehyde and ketone groups in the linear form), would make sucralose much less stable than a pure chlorocarbon like DDT.
    Of more interest to me, as a former molecular biologist, is why molecules like aspartame are so much sweeter (if you can forgive the aftertaste—I can’t, either) than sucrose. You probably already know this, but in the “sweet” taste receptors on our tongue there is a hydrophobic pocket right at the site where the sweet molecules bind. Thus, sucralose, which is less hydrophilic than sucrose, binds more tightly, and aspartame, with its big ol’ phenyl group, binds much more tightly. And this makes biological sense: given that we need to eat hundreds of grams of carbohydrates to get our daily calorie requirements, there isn’t much sense in rewarding ourselves for eating something that contains only a minute quantity of sugar. Hence, the sweet taste receptor shouldn’t be very efficient at detecting sucrose. Also, it is to our benefit that the sweet receptor can generalize somewhat to amino acids (for example, glycine is so named because it tastes sweet).

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