This is the next installment of Snoozical Rambles about Toxicology, which may or may not becomes a weekly theme. If you are new here, you should go read my disclaimer.
Today, I’m all jazzed about artificial sweeteners, specifically aspartame. This is a subject near and dear to my heart, which is to say: don’t fuck with my diet coke, man. More often than not, when people find out I’m a toxicologist, they give me the side eye and ask me why I’m drinking that diet soda because don’t I know that aspartame will make holes in my brain or give me cancer etc.??
Nope! No it won’t! Aspartame is so, so, SO non-toxic. “But wait! Susie, you said before that the dose makes the poison! And I’ve seen you down a two liter in one evening!” Yes, you are correct – the dose DOES make the poison – and aspartame doesn’t become a poison unless you are drinking ridiculous volumes. Here are some numbers: the FDA acceptable daily intake (ADI) for aspartame is 50 mg per kg of body weight. That equates to over 3 grams of pure aspartame per day for a 135 pound human, on up to 4.5 g for a 200 lb person. There are about 125 mg of aspartame in a 12 oz can of diet coke, my drink of choice – so that’s about 10.4 mg per ounce. In order to reach my daily limit of aspartame, I’d need to drink nearly 300 ounces of diet coke. In a day. I’ve tried, I’ve done some serious focused work, and the most I’ve ever had in a day is two 2 liters. That’s ~135 ounces. I had to use a bendy straw, and I had several people cheering me on.
Ok, so maybe you’re thinking, wait, that’s not that far from the limit! 135/300, that’s almost halfway there! Right, so that 300? That is equivalent to the 50 mg/kg/day FDA ADI. That number is health protective, i.e., well below an exposure that could be expected to cause any toxicity in humans – you could ingest that much, every day, for your whole life and experience no health effects.
The ADI is based on a LOT of science: a host of epidemiological studies of humans, as well as long term exposure studies in animal models. Taking the animal studies first: the National Toxicology Program, an actual reputable research organization, conducted life time exposure studies in rodents with daily intakes spanning
In acute studies in rodents, no effects were observed at doses exceeding 10,000 mg/kg. That’s the equivalent of a rat pounding 20 cans (240 oz) of diet coke at once. Or a human drinking 5600 cans of diet coke. THAT IS A LOT OF DIET COKE, even for me. In chronic, lifetime cancer bioassays in rodents, they fed doses up to 12,000 mg/kg/day for periods up to two years (the lifetime of most rodents), and were unable to detect effects. NO EFFECTS. You have to believe me when I say that this INSANE – laboratory rodents LOVE getting tumors, and they just WOULDN’T DO IT.
Epidemiological studies in humans have been similarly boring – no effects, no significance, nothing, nothing. There was one by Olney et al. (1996) that tried to correlate aspartame with brain tumors, but that study has been roundly dismissed due to wonderful, ethical things like fudging and misrepresenting data. Every other study, and there have been MANY, has found no effects. NO EFFECTS.
Aspartame: the least toxic substance ever, except maybe water.
All the cold hard facts (numbers) in here came from the 2007 Safety Evaluation by B.A. Magnuson et al. Here is the evaluation summary, and here is the evaluation itself (though you’d have to pay or have journal access to read it).