‘Aspartame Causes Cancer’ Was a Classic Internet Hoax

The aspartame myth goes back to a letter circulating on the ‘90s internet

A woman adds artificial sweetener to a drink. The paranoia over the health dangers of aspartame can be traced back to an early Internet hoax. iStockPhoto/Highwaystarz-Photography

Look, nobody’s telling you that you should drink diet beverages all the time. But when you do have a drink sweetened with aspartame, you don’t need to worry about getting cancer, multiple sclerosis or depression any more than you would with any other single substance you consume.

Aspartame was patented on this day in 1970 as Nutrasweet, one of the names it’s still sold under. Unlike that name suggests, it’s not particularly nutritious, but it’s not intrinsically bad for you like, say, smoking. Because of people’s concern around this substance, it’s been “one the most exhaustively studied substances in the human food supply,” according to the FDA. And it’s safe to consume, also according to our federal monitoring agency for foodstuffs.

The FDA is a reputable source. What didn’t come from the FDA was the mid-90s aspartame panic. Persistent rumors about aspartame’s links to seemingly every condition under the sun go back to what’s known as the “Nancy Markle” allegations: a letter that linked “ASPARTAME DISEASE!” to fibromyalgia, among other things, and said MS was methanol toxicity rather than a pernicious autoimmune disease.

It was supposedly written by Nancy Markle, who had recently “spent several days lecturing at the WORLD ENVIRONMENTAL CONFERENCE” on aspartame. A Google search of "world environmental conference" almost solely yields results related to Markle’s aspartame conference, which supposedly happened in 1995. 

The kicker: Nancy Markle never existed. The letter was written by an aspartame truther named Betty Martini, writes librarian Paul S. Piper for Western Washington University. She's still around online, if you're interested. But the letter’s use of all-caps writing and conversational (read: poorly punctuated) tone to convey “scientific” information probably looks familiar for anyone who's spent any time on the internet.

The letter made its way around the internet for years and is still around as chain mail. It's the canonical example of an internet hoax, and it spread quickly. In a very different letter printed in The Lancet, one of medicine’s foremost journals, in 1999, researchers wrote that they had found over 6,000 websites mentioning aspartame, with many saying it was the cause of “multiple sclerosis, lupus erythematosis, Gulf War Syndrome, chronic fatigue syndrome, brain tumors and diabetes mellitus among many others.”

The internet was relatively small back then, and it had been growing rapidly every year since 1995, according to Internet Live Stats. The aspartame hoax grew with it, as people tried to navigate this new technology. Virtually none of those 6,000 websites offered sound evidence, the Lancet researchers say, sticking to anecdotes. Some attempted to sound more scientific, by citing the chemical products created when our bodies digest aspartame: methanol and phenylalanine. That part is true. Aspartame does break down into methanol and phenylalanine. But that shouldn't be scary.

“Over time,” writes PBS in a story about aspartame misinformation, “methanol can produce the known carcinogen formaldehye. While this might seem scary, [a video released by the American Chemical Society] claims that the body actually produces and uses 1,000 times more formaldehyde than you could consume through aspartame. After helping to make important proteins, formaldehyde gets turned into formic acid and exits the body through urine.” The other chemical, phenylalanine, isn’t linked to depression, they write. And there is eight times as much of it in milk as in aspartame.

Almost 20 years after the letter, people still question aspartame. Out of all of the substances in our diet, why this one? It probably all goes back to the perception that “chemicals” are bad for you, whereas sugar, an honest, natural sweetener must be good.

While the myths about aspartame are relatively inconsequential in direct terms (the FDA isn’t going to withdraw aspartame’s approval), academic Adam Burgess writes that the public uncertainty created as a result of the aspartame myths is still an issue “in the context of the importance of promoting sugar-free alternatives, in a world where challenging obesity is a high priority.”

Editor's note: a previous version of this article stated that the medical journal The Lancet is an American journal. We regret the error.

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