Aspatame and Audrey

From the archives: Molecule of the Month, February 2009

To begin my story, I need to introduce you to Audrey my mother in law to be. A force to reckoned with at the best of times, Audrey is never less of a menace than when she broaches the subject of aspartame. ‘Don’t drink that,’ she once cried, as I innocently lifted a bottle of my favourite carbonated beverage (lilt, mon) to my lips during the first year I was dating my newly betrothed. Smacking the plastic from my grasp, she launched into a tirade of abuse about how aspartame could give me a whole host of ailments. As I imagine most people would, I avoided drinking anything fizzy and pineapplely for a few days: or at least until I really fancied another can. Of course, I didn’t forget Audrey’s words of warning, but simply chose to ignore them on the grounds that I’m 22, in perfect health and refuse to accept that anything might ever change that.

I’m not one for drinking lots of Coke as a rule. I think this is based on the ‘experiment’ we conducted with Mrs. Webb when I was in class 3 at primary school. We immersed a tooth (these were in ready supply, us being at that age where you endlessly concoct barmy schemes for dislodging baby teeth involving loops of string around door handles) in a test tube of Pepsi for a week. Believe it or not, the tooth was a shell of its former self after this treatment, although on reflection perhaps this test might have over estimated the typical amount of time Pepsi spends in the mouth.

Even so, I do indulge in a cheeky Coke every so often and although what I might be doing to my teeth doesn’t really enter my mind, I do find myself wondering if Audrey had a point about Aspartame.


Aspartame (the structure of the molecule is shown above) is a synthetic sweetener, often found in diet soft drinks as a replacement for sugar. Aspartame is about 180 times sweeter than sucrose (i.e. the sugar monomer which you get in Tate and Lyle bags). This is great for dieters as soft drink companies can use 180 times less aspartame than sucrose, which means a lot less carbohydrate mass in the drink and so fewer calories.
The compound in question was discovered by Jim Schaletter in 1965. He made it accidentally whilst trying to prepare a dipepetide (that is two amino acids joined together) which was at the time thought to be a promising drug candidate for the treatment of gastric ulcers. He accidentally licked his finger after working with the compound and to his (pressumable) amazement it was as sweet as a biscuit!

Schaletter, man of sagely intelligence that he was, decided to scrape the contents of his round bottomed flask into his coffee the following morning, to make sure it really was the compound, and not some disregarded doughnut remnant from his after dinner indulgences of the previous night, which had caused the aforementioned sweetness. Typically a chemist who tempts fate in such a way might expect a short trip to a long stay in hospital as his wages, but Schalatter – the lucky so and so – on realising his coffee was sweetened to perfection, started a chain of events which led to his company making billions of dollars a year: You will now find aspartame in a huge range of products: diet and regular soft drinks, confectionary, cereals and even yoghurts.

So why are people concerned? It is well known that Aspartame breaks down to aspartic acid, phenyl alanine and methanol when ingested. Potentially this could be worrying, because:

1. When exposed to biological conditions methanol can be converted to formaldehyde (the stuff you see dead things floating in at a school science laboratory) which is a known carcinogen.

2. Phenylalanine and aspartic acid are both neurotransmitters which up- regulate the firing of the neurons in your brain. They are part of a complex metabolic system and can be converted into other neurotransmitters such as dopamine and adrenaline. The theory runs that ingesting extra phenylalanine will mess up the delicate neurotransmitter balance and could have unpredictable effects on your mood. Potentially, since phenylalanine is an up-regulator, if you have an awful lot of it you could go a bit haywire.

3. In a recent study, aspartame itself has been shown to be an intercalator of DNA (1), which means it jams itself snugly into the gaps in the DNA double helix. This causes problems when the DNA has to be ‘unzipped’ for copying when the cell replicates. We understand enough about DNA replication and its connections with cancer to know for certain that this is in theory bad news – but scientists don’t know how this particular intercalation might affect us at the moment.

The points above are facts, however the arguments for aspartame being safe say that the amount of these substances which actually reach a site in the body where they can do any harm is very, very small. In any case it is also true that we eat and drink foods containing far higher concentrations of these substances on a daily basis. For example an average glass of milk provides 6 times more phenylalanine and 13 times more aspartic acid than the equivalent amount of aspartame sweetend beverage (2).

In public, the debate about aspartame still rumbles softly. Indeed, ‘safer’ alternatives such as sucralase (marketed as splenda) have been developed to combat these public fears, whether they are realistic or not.

In fact, all the scientific evidence is against any issues with the safety of aspartame. Repeated toxicological studies on various animals and human subpopulations (infants, the elderly and diabetics for example) have failed to find any ill effects caused by the sweetener (2). Millions of people consume products with aspartame in everyday and it does not appear to do them any harm at all.

To finish with, and in the interest of preserving my engagement, I’d just like to add here that I may have embelished some of incidents in which I cite Audrey’s involvement for comic effect. In fact she is a lovely woman and I can only remember her knocking a drink from my hand once, and this was in an aspartame-unrelated situation. Honest.


 (1) G. A. Karikas et al., Clin. Biochem., 1998, 31, 405 – 407.
(2) H. H. Butchko et al., Regulatory Toxicology and Pharmacology, 2002, 35, 1 – 92.

This entry was posted in Uncategorized and tagged . Bookmark the permalink.

17 Responses to Aspatame and Audrey

  1. Clearly this was a man in desperate need for THE TALK on OH&S. I never got to taste anything good in Chemistry… except for this one time when we made sherbert, that was awesome!

  2. Pingback: Open Lab selections 2009 « Seeds Aside

  3. Pingback: Open Laboratory 2009 results « Bench TwentyOne

  4. Kris says:

    I like your article. It is even-handed and gives the reader a sense that though we do not know for sure if there are ill health effects from ingesting aspartame there are some solid scientific reasons for concern. My concerns with the aspartame issue are 1.) I cannot stomach the taste of the stuff and even if i was made to drink three diet sodas a day don’t think i could ever train my throat to enjoy it. and 2.) When the billion dollar industry of artificial sweeteners first came to market the political gurus in charge of approving them 9
    even when the FDA expressed som econcern) were some of the most corrupt our country has ever seen. enter – Donald Rumsfeld. I give a rundown of this whole story in an old post you can find here…

    • joshuahowgego says:

      Thanks for your comment, Kris. I’m intrigued that you hate the taste of aspartame; I don’t think I can really tell difference between the taste of aspartame and non-aspartame sweetened products. But that might just be because the stuff is so prominent that I’ve never tasted a soft drink without it?! Maybe I could mock up some kind of amusing / crude experiment to see if I can tell the difference, and post it here. I will now head to your blog and swat up further…

  5. Chelsea says:

    My mother will not touch it since the late 70’s because she thinks it will either cause an epileptic attack or interfere with her epilepsy medicine. I cannot even get her to try drinks with the new sweetners. I have not been able to locate any research on this. If anyone knows of any, please let me know.

  6. joshuahowgego says:

    Chelsea – you could start with the two references in the post? One of them was quite thorough – although after 6 months, i’ve forgotten which one..

  7. Jeremy says:

    (just saw this on the top science blog list, congrats)

    The reason I don’t eat aspartame is the way it is sensed by the body – Gustducin –

    Gustducin is the receptor for sucrose and other sugars, which leads to the sweet taste when aspartame binds instead of sugar. However, Gustducin is not found only in the mouth, but also in the gut ( and in the pancreas ( The role of gustducin there is unknown, but if it is at all related to glucose metabolism regulation, there is potential for trouble (diabetes) when the body expects sugar but doesn’t get any. The fact that aspartame is “200 times sweeter than sugar” also indicates it has a high affinity for the receptor, possibly worsening the problem.

    That said, this is conjecture, and long term studies show no problems. For me though, better safe than sorry.

  8. joshuahowgego says:

    I didn’t know anything about Gustducin – which just shows you can never trust anything you read on a blog!

    I think you make quite a wise observation. I can see the logic of why aspartame might cause ‘trouble’.

    However, I think at some point we just have to stop worrying. As you say, none of the evidence shows a link between diabetes and aspartame. Diabetes UK (a UK charity giving advice on diabetes management) have a position statement on aspartame which reflects this:

  9. Ash says:

    I avoid aspartame mostly because every time I drink something with it I get a splitting headache (I know other people with the same problem – I’ve heard it’s due to a similar mechanism to MSG causing headaches). I don’t see any evidence of major long-term health issues though – there are the Ramazzini Institute studies linking it to cancer, but they seem to find every substance they test causes cancer, which leads me to treat their work with a bit of skepticism.

  10. canadapaul says:

    Thanks for this. I have a running ‘argument’ with a coworker who insists that I’m poisoning my body with Aspartame (he calls me ‘Aspartame-Boy’), yet refuses to see the potential harm he does to his body and brain by chowing down on McDonalds twice a day, consuming mass quantities of sugar laden soft drinks, not to mention his love of alcohol…

  11. Neuropharma says:

    Congrats for being on the top science blog list!

    My mom is exactly like Audrey. She always warns me from aspartame and says that drinking/eating the “natural thing” (she means sucrose) in moderation is much better than having anything containing aspartame. I did my own research and I found most references pointing out, as you mentioned, that no real risks have been found to be associated with aspartame consumption. I tried convincing my mom but in vain. I switched to sucralose however, but she’s not so comfortable with me doing that either. But I know I am!

  12. Pingback: Mum Science « Bench TwentyOne

  13. Maria Egervari says:

    Not exactly all scientific studies have proven Aspartame’s safety:

    Spring 1971– Neuroscientist Dr. John Olney (whose pioneering work with monosodium glutamate was responsible for having it removed from baby foods) informs Searle that his studies show that aspartic acid (one of the ingredients of aspartame) caused holes in the brains of infant mice. One of Searle’s own researchers confirmed Dr. Olney’s findings in a similar study.

  14. Pingback: Shorthand books from 1913 | bench twentyone

  15. Arran Frood says:

    Great article. My mum came at me with some of this as she has lupus, which many people blae on aspartame.

  16. Pingback: Aspartame and Audrey « Josh Howgego

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s