Artificial Sweeteners - Aspartame

A few weeks back I had the privilege to go on a road trip to Batemans Bay with some of my friends. It was a wonderful break from work, and allowed me to catch up with friends that, due to distance and/or conflicting schedules, I may only see a couple of times per year.

One morning, we were having breakfast, in preparation for a big day. Sitting at a big table, we were eating, drinking and generally being merry. During breakfast, one of my friends leant over towards me and gestured towards the diet soda that I was drinking, and began the following exchange:

Friend: "Hey, you shouldn't drink that!"
Me: "Yeah, it is a bit early in the day for soft drink, but I don't feel like coffee or juice this morning..."
Friend: "No, you shouldn't drink that. Didn't you know that the fake sugar in that was banned in the UK? It causes cancer!"
Me: "Really? I'd wager that a company can't distribute a product with a known carcinogen, and not be the subject of a law suit."
Friend: "No, it's true! I read it somewhere..."

"I read it somewhere"... A line that always makes me cringe inwardly. Perhaps it is the scientist in me, but I do prefer a good reference as opposed to an anonymous source.

At any rate, just what was my friend referring to? The nods of assent he received from my other friends from around the dining table made it seem that this substance was well known. Well, it would appear that based on my choice of beverage that fateful morning, it seems likely he was referring to aspartame, an artificial sweetener used as a sugar substitute.

Oh how sweet it is... Approximately 200 times sweeter than sucrose, in fact!

So, why does the above molecule have such a bad reputation? Well, aspartame was discovered way back in 1965 by a chemist working for G.D. Searle & Company. Originally synthesised in order to produce a potential antiulcer drug, the sweetness of aspartame was discovered when a chemist licked his finger in order to pick up a piece of paper. Evidently this chemist was not wearing gloves at the time, as during the aforementioned synthesis, his finger had been contaminated by aspartame.

Shortly after approval by the Food and Drug Administration, a chain letter posted under the pseudonym of Nancy Markle, warning of the inherent risks posed by aspartame. The alleged dangers of aspartame included an increased incidence of multiple sclerosis and brain tumors, and a dire warning that when exposed to heat, that aspartame decomposes to produce methanol, and hence consumption of products containing aspartame could lead to methanol poisoning.

Indeed, there have been numerous claims regarding aspartame and its relative safety for human consumption. The safety of aspartame has been studied extensively, and has repeatedly been deemed safe for human consumption. Regarding intake and consumption, the FDA has set the acceptable daily intake (ADI) of aspartame at 50 mg/kg of body weight. To put this into perspective, a 350-375 mL diet soft drink may contain around 180 milligrams of aspartame. For a 75 kg individual, it would therefore take approximately 20 cans of diet soft drink to exceed the ADI of aspartame.

One of the other claims made against consumption of aspartame is that it breaks down in the body to form highly toxic compounds, including aspartic acid, phenylalanine and methanol.

•  Aspartic acid: One of the most commonly encountered amino acid in a regular diet. A rather fascinating clinical study by Magnuson et. al. (2007), however, found no evidence of neurotoxic effects derived from consumption of aspartic acid. 
• Phenylalanine: One of the essential amino acids, one is likely to consume far more phenylalanine during their regular diet than from diet soft drink. That being said, those with phenylketonuria are advised to abstain from food products that contain significant amounts of phenylalanine or aspartame. 
• Methanol: The metabolism of methanol to formaldehyde, and then formaldehyde to formic acid, is implicated as one of the dangers of aspartame use. It should be noted, however, that the amount of methanol absorbed by the body as a result of consuming aspartame-containing products, is less than what would be absorbed if one consumed various fruit juices or fermented beverages. Indeed, in the article by Magnuson et. al. (above), it was found that consuming the maximum expected amount of aspartame did not result in elevated blood levels of methanol, formaldehyde or formic acid.

As for claims regarding aspartame's alleged ability to cause brain cancer, no significant links have been found to date. One study by European Ramazzini Foundation of Oncology and Environmental Sciences (ERF) alleged that aspartame is a carcinogen at normal dietary doses. However, this study has been discredited, and in fact, the European Food Safety Authority evaluated this study back in 2010. This evaluation found that there were multiple significant design flaws in the study by the ERF, and that as such, there was insufficient evidence to suggest that the safety of aspartame needed to be reconsidered.

Claims have also been made that have alleged that consumption of aspartame may result in negative neurological and psychiatric symptoms, including seizures, headaches and mood swings. Lajtha et. al. (1993) found that with regards to the biochemistry of aspartame, there is no evidence that aspartame could conceivably lead to neurotoxic effects.

So there you have it. One artificial sweetener and a number of concerns. Though it would not surprise me that in the future the safety of aspartame will be reviewed once again, for the moment it is crucial to note that there is no evidence to suggest that the use of aspartame represents any real cause for concern.

Now where did I put that can of soda...?

Organic stuff is good for you, right?

By presenting workshops and giving the occasional talk to high school students, I always make a point of allowing them to ask any relevant questions on science, chemistry and so on. I also try and ask them questions that make them think about the world and how it works. One of my favourite questions to ask is:

"Are organic things good for you?".

Most students surmise that I am referring to organic food, and respond with an emphatic "Yes!". This is a reasonable response, as depending on their year level, a number of students will not have encountered organic chemistry at this point in their schooling.

I then press the matter, and ask what does the term "organic" mean. In reply I'm told that it means that organic things are safe, natural, and so on. In response I ask whether they would eat arsenic, as it is naturally occurring. I explain that just because something is naturally occurring, it doesn't necessarily follow that it is safe.

The next question is whether they would ingest something like a cyanide salt, and receive an emphatic "No!" in response. This of course raises the question "Why?". After all, a compound like sodium cyanide is organic, and as the students have told me, organic things are safe and good for you.

At this point an explanation is in order, and discuss the different meanings attached to the word "organic". In particular, to scientists and chemists, "organic" describes a wide range of carbon-containing compounds, because hey, that's how we roll.

In short, it's always enjoyable to share knowledge during these workshops, and allowing the students to gain a more detailed understanding of the world around them.

Until next time,

Nathan

Drugs Policy - Ecstasy

Though drugs policy is certainly a contentious issue, it is something worth commenting on. Walking through Sydney the other day, I happened across a poster regarding the production of ecstasy, and the nasty chemicals that are involved in its production.

This gave me pause. Certainly, harm minimisation and decreasing the incidence of recreational drug use (especially in teens) is ostensibly a worthy cause. However, this poster concerned me, not due to its portrayal of a clandestine laboratory, but the text associated with it:

"Made using drain cleaner, battery acid or even hair bleach. Then popped in your mouth"

Granted, a number of people would not necessarily understand the implications of this poster if it said:

"Made using sodium hydroxide, sulfuric acid or even hydrogen peroxide. 

Then popped in your mouth"

That being said, I feel that this poster is disingenuous, if only because it attempts to provoke fear, in particular, fear of chemicals. As mentioned in an earlier post, chemophobia is a tricky issue in modern society, where awareness of the health implications of exposure to toxic compounds is increasing. This awareness, however, has become associated with an irrational fear or distrust of, dare I say it, chemicals!

So, back to the poster. A wide range of synthetic routes are available for the production of MDMA from its precursors. The poster in question appears to reference a specific synthetic route, starting with isomerisation of safrole to isosafrole. Indeed, this method does involve the use of sulfuric acid, hydrogen peroxide and a strong base, as well as various other chemicals. In this regard, the poster is accurate, in that a clandestine laboratory may indeed use this particular scheme. 

At this point, we must ask ourselves what is the purpose of including the named chemicals in the above poster? It isn't to provide a cheat sheet a person on the street can use to start up their own little clandestine laboratory in suburbia. Again, it comes back to the use of scientific and chemistry-related terms to invoke fear, so as to scare off any would-be first time users of ecstasy, because hey, it contains chemicals.

To be blunt, and not to condone the production of recreational drugs, but one would imagine that a drug manufacturer would try not to actively poison their clientele. Of course, the use of adulterants and cutting agents to increase the bulk of a drug, or to alter its psychoactive effects are nothing new, and have been reported on. It is also unfortunately true that there have been reported fatalities due to ecstasy, whether due to overdose, adulteration and/or  polydrug abuse.

Back to the underlying element of chemophobia though. The three named chemicals in the above poster are sulfuric acid, hydrogen peroxide and sodium hydroxide. Though I dare say I don't often encounter sulfuric acid in everyday life, I do come into contact with hydrogen peroxide and sodium hydroxide. Regularly, in fact. Worse still, despite the warning of the poster, I put them in my mouth! Fear not, I don't swallow them. There is hydrogen peroxide in my mouthwash, and sodium hydroxide in various toothpastes. As for sulfuric acid, it is vital for a number of chemical reactions that produce a wide range of compounds, in particular those that are involve nitration in their synthesis.

Hmm... Perhaps this will make an interesting experiment for myself, and something I can report back on. I will endeavour to look at some everyday objects I encounter, and look at the chemicals that are present in them. 

Until next time, thanks for reading,

Nathan

On Chemophobia - Dihydrogen Monoxide

Perhaps one of the more interesting issues I encounter as a chemist is that of chemophobia, an irrational fear of chemicals.

In my experience it emerges as a lack of understanding of what chemicals are, the fact that everything in our world is composed of chemicals, and most important of all, a lack of understanding of the relationship between dose and effect.

In relation to dose, the German/Swiss alchemist Phillipus Aureolus Theophrastus Bombastus von Hohenheim, better known as Paracelsus, said it best:

"All things are poison, and nothing is without poison; only the dose permits something not to be poisonous" 

Or as it is more simply put:

"The dose makes the poison"

One of the advantages of working with high school students in forensic/chemistry workshops is that it allows me to gauge their understanding of the chemical world. Whether it be a discussion on what the term "organic" means, the painful debate over the safety of vaccinations, or what everyday objects contain, the questions and feedback I receive are truly fascinating.

Perhaps one of my favourite demonstrations draws on the rather popular Dihydrogen Monoxide (DHMO) hoax of years gone by. In my demonstrations, it begins by politely asking for volunteers from the audience, and if none are forthcoming, a bribe of crime scene tape works a charm. After the volunteers are assembled, I don my labcoat, goggles, and some nitrile gloves before continuing.

I then ask my volunteers to produce one of their hands, preferably their non-writing hand, before nervously producing a vial containing that dastardly compound, DHMO. After gingerly placing a drop on each of the volunteers' preferred and proferred hands, a short statement regarding the dangers of DHMO is read out. Ususally DHMO is switched out for the IUPAC name "oxidane", in order to throw off any students aware of the DHMO hoax.

Hide the children! It's oxidane!

The students are then questioned on any ill effects that they are experiencing following exposure. The effects I've had rattled off to me are curious, and have included anything from tremors, sweating and increased heart rate, to headaches, stomach cramps and dizziness. To quell any further worries, the ruse is revealed, and the students calm down significantly.

The goal of all this is to demonstrate that an awareness of chemistry, if not an active interest in it, combined with a healthy dose of skepticism, can prove invaluable.After all, it pays to be aware of the world around you, and to have at the very least a basic knowledge of how things work. This brings to mind a very salient quote by Neil Degrasse Tyson:

"If you're scientifically literate, the world looks very different to you"

In future posts, I will further discuss chemophobia and how people perceive chemicals, more broadly, chemistry.

Well, that wraps up this post. Thanks for reading!