Science Friday: Aspartame

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).

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12 Responses to Science Friday: Aspartame

  1. I LOVE THIS SO MUCH. People who give me the side eye every time I drink a diet coke and say “You know, soda is going to kill you…” need to find a new hobby.

  2. jonniker says:

    Diet Coke while pregnant: Yes? No? (Says the mother of two children who were basically born steeped in amniotic fluid made from aspartame. They seem OK.)

  3. Lisa says:

    When I was pregnant with H, I could NOT stomach anything with aspartame. For whatever reason, it made me gag like nothing else (unless you count the smell of Final Touch fabric softener).

    Still today, LO THESE 19 YEARS LATER, I can handle Diet Coke and Diet Pepsi just fine, but diet citrus-based drinks? LIke Diet Mt. Dew and Diet Sprite? Taste like acidic pee to me. (Not that I’ve ever DRANK pee, mind you, just what I imagine acidic pee would taste like.)

  4. Lauren says:

    I love this!

    My mother–who smokes, for heaven’s sake–tries to give me a hard time about drinking Diet Coke. I just roll my eyes at her, because I’m completely incapable of taking health advice from someone who’s sucking on a Virginia Slim.

  5. Lisa says:

    I will say, for you too young to remember, that Diet Coke with saccharine was the SHIT. SO GOOD. If they ever come back and say saccharine really DOESN’T cause ass cancer or whatever, Imma stab somebody. #saccharine4eva

  6. gorillabuns says:

    So this means I can pounding my Diet Dr. Pepper again?

  7. herewegoajen says:

    Hmm, how about just that it tastes bad, then? Give me regular Dr. Pepper or give me death! Okay, maybe not death, maybe just no diet drinks. Actually, I don’t even like soda that much so maybe I am not the best example.

    Now, I have heard that people with kidney issues should not drink dark colored sodas. Do you have any knowledge of this? Or did someone make this up because it sounds sensational? And I am delighted that you have become my new expert on all things chemical/soda/etc. ;)

  8. Gaby says:

    This “laboratory rodents LOVE getting tumors,” cracked me up! Seriously, though, there’s GOT to be something to McDonald’s version of Diet Coke, right? It is laced with crack, or something, because it is its own beast. Count me as another person who loves these posts of yours.

  9. Nicole says:

    “…laboratory rodents LOVE getting tumors, and they just WOULDN’T DO IT.”

    THIS. This is hilarious and will now be my justification for all the Diet Pepsi I drink. And in your honor, I just cracked the seal on another 24-oz.

  10. Melissa says:

    I know I’m late to this game, but I’m glad I read this anyway. And I’m going to go ahead and believe a complete internet stranger who seems way smarter than me about this stuff..and I’m going to buy Diet Dr. Pepper again. I miss it. I recently switched to Pepsi One which is made with splenda..is that better/worse/same than aspartame? Thanks for this post.

    • snoozical says:

      I haven’t looked closely at Splenda, but my bet would be that it is similarly not at all toxic, not even a little bit. Welcome back to tasty beverages!

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