As a kid, I remember that my dad used an artificial sweetener on his cereal in the morning. It was a clear liquid that came in a little squeeze bottle and had the now-familiar NutraSweet “swirl” on it. It also came with a warning on the label – something about using too much of it. I was happy to let this warning keep me from using it because of my intense dislike of the awful flavor it imparted. You don’t hear too much about it these days, but for a while there was a sort of anti-aspartame movement, as well as a myriad of (completely ridiculous) health claims that circulated (You can read some of them at Snopes) about the stuff.
The ubiquitous artificial sweetener came up in conversation a few weeks ago with a friend of mine. She expressed her dislike of it in vague terms, not being able to quite articulate why she disliked it, but her argument centered mostly1 around the fact that it’s an untested compound that we’re basically experimenting with ourselves on, a synthetic chemical, and that since sugar is natural, it’s clearly better for our bodies. And I want to address some of these claims specifically, and the intuition that most people have that natural or organic foods are better and more healthy for us.
Aspartame was discovered in 1965 by accident at Searle (Which is now Pfizer) by James Schlatter, a chemist who was trying to invent a new kind of drug. It’s about 180 times as sweet as sugar, which is part of what makes it such an attractive sweetener – you only need tiny amounts to get stuff sweet. It doesn’t cook well and has a limited shelf life, which is why in recent years we’ve seen its use declining as it gets supplanted by sucralose. Sucralose is three times as sweet as aspartame and retains its chemical structure under heat and on the shelf, which makes it more attractive.
In 1975, because of adverse effects with other drugs that Pfizer had developed, the US FDA launched an investigation into their research methods using 25 papers submitted to them as a test pool, and upon review cited “serious deficiencies” in their operations. The FDA then worked to authenticate the studies themselves, including their methods, and in 1979 concluded that the studies were sound science. The FDA approved its use in carbonated beverages in 1983, and its use in a bunch of other stuff in 1993. Finally, they removed all restrictions on its use in 1996. The EU approved it 1994. The EU’s Scientific Committee on Food again reviewed safety studies on aspartame in 2002, and again in 2006, the European Food Safety Authority reported that the established acceptable daily intake was appropriate after reviewing yet another set of studies. The Nutra-Sweet Corporation published their own review of the published safety information in 2002, and stated:
Over 20 years have elapsed since aspartame was approved by regulatory agencies as a sweetener and flavor enhancer. The safety of aspartame and its metabolic constituents was established through extensive toxicology studies in laboratory animals, using much greater doses than people could possibly consume. …Several scientific issues continued to be raised after approval, largely as a concern for theoretical toxicity from its metabolic components — the amino acids, aspartate and phenylalanine, and methanol — even though dietary exposure to these components is much greater than from aspartame. Nonetheless, additional research, including evaluations of possible associations between aspartame and headaches, seizures, behavior, cognition, and mood as well as allergic-type reactions and use by potentially sensitive subpopulations, has continued after approval. …The safety testing of aspartame has gone well beyond that required to evaluate the safety of a food additive. When all the research on aspartame is examined as a whole, it is clear that aspartame is safe, and there are no unresolved questions regarding its safety under conditions of intended use.
So it would appear that aspartame stands out as a product that has been thoroughly researched and safety-tested, and yet somehow people still feel uneasy about the sweetener. People point out that it turns to formaldehyde in your system, a fact that is true but entirely irrelevant – formaldehyde is a natural by-product of methanol digestion. (For example, a serving of non-fat milk provides about six to nine times more phenylalanine and 13 times more aspartic acid than the same amount of beverage sweetened with aspartame. A serving of tomato juice provides about four to six times more methanol than the same amount of aspartame-sweetened beverage.2 It’s not a medically significant amount either way.)
The larger question then remains: if thorough safety testing and twenty years of safe addition in foods have shown us no reason to ban or otherwise be wary of a particular product, why do some people still continue to have reservations about its use?
The answer to this questions varies – but the general feeling that seems prevalent among people reluctant to use a product like aspartame is that it’s a chemical (chemicals are scary!) and synthetic, unnatural, and anything produced by a huge company is obviously tainted with Corporate Hate Energy. If it doesn’t occur in nature, it can’t be good for you, right? The stuff that the earth produces was good enough for the human race for tens of thousands of years, why should we go messing around with that kind of perfection?
Collectively, this set of ideas and attitudes can be known as an Appeal to Nature, and there are several problems with this kind of thinking. The first is that “natural” is a loaded term, and tends to be unconsciously equated with “normal” – a simple and incorrect bias. How do we define natural? Take the example of the modern banana.
Not pictured: a natural food.
A banana. What could be more natural, more wholesome, more yellow? I’ll tell you what: a wild banana. You thought the delicious yellow Cavendish banana you’re used to seeing represented the pinnacle of nature’s ability to produce food? You would be wrong, my friend. The modern banana is the culmination of many, many years of forced modification using selective breeding. A modern Cavendish banana has, in fact, been so modified that the plant that produces them is sterile. That’s right: Mother Nature abhorred what we did to bananas so much that she won’t let them have sex anymore.
Of course, I’m being sarcastic. My point is that we’ve been eating “unnatural” things since man first figured out how to cross-polinate species, and we’ll continue to do it in the future. And that’s a good thing! The Cavendish would have never occurred in nature, neither would the amazing wheat varieties created by Norman Borlaug, credited with saving billions of lives with his genetic modification program for the staple crop. (If you’re unfamiliar with Norman, check out the Wikipedia article on him. He was an amazing human being.) We use chemicals around our bodies, and in them, every day that don’t occur in nature without ill effect: Ibuprofen, bananas, rayon, Teflon, toothpaste, shampoo, soap.
The point I’m trying to make is this: there is nothing fundamentally different between drinking a soda sweetened with aspartame and a soda sweetened with sugar. They’re both chemicals. Everything is made of chemicals. The fact that something is synthetic doesn’t fundamentally change the fact that it’s made up of various combinations of the same 118 (currently) known elements.
Which brings us to our next question: how much testing is required before we decide that a certain food or additive or child car seat or what have you is “proven” safe? The short answer is: you can’t. You can’t be sure that we won’t discover tomorrow that tomatoes are carcinogenic, or apples cause brain tumors. But we can draw strongly upon what we know about food, science, and chemistry, and extrapolate from that base of knowledge – a Bayesian Analysis.
A Bayesian Analysis is a form of statistical inference in which existing evidence or observations are used to calculate the probability of a hypothesis. For instance, if tomorrow we created a new cultivar of fruit, say a cross between a kiwifruit and a strawberry, do you imagine that the FDA would require ten years of testing and restrictions before kwiberry was allowed on the market? Of course not. We know enough about strawberries and kiwis and chemistry and food production that we can infer a very strong probability that such a hybrid would be safe. We’d probably do some basic testing to make sure it wasn’t somehow producing known toxins through some unknown process, but after that, kwiberries would be all over the place. We not only know a lot about chemistry, we know a lot about the chemistry of stuff we put into our food, and how our bodies are likely to react to it.
And it’s the same thing with aspartame. The chemistry of the aspartame is so well-understood and has been studied ad nauseum even after its approval by the FDA, and found to be safe at every turn. At some point, you’re going to depart from realm of rationality and evidence to continue supporting the notion that its somehow harmful, or that its effects on human biology aren’t known. They are known, and have been for years.3 When used at the levels that you’re going to find in any food that you’re likely to eat, aspartame is a harmless – though admittedly not very tasty – way to sweeten things up. To quote the unflappable Brian Dunning of Skeptoid: “When you hear claims that are supported only by a fringe minority that’s in opposition to the scientific consensus, you have good reason to be skeptical.”
So enjoy your Diet Mt. Dew.
Exit, stage left.
Sparks
1: R: If you’re reading this, and want to correct anything I asserted about what you said / claimed, let me know.
2: Relationship Between Aspartame, Methanol and Formaldehyde Explained
3: Most of these arguments apply to genetically-modified foods, too, but that’s a whole ‘nuther discussion.
We have a mix between a kiwi and a strawberry. Its called a snapple.