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Home » Pepsi and aspartame – an unscientific decision

Pepsi and aspartame – an unscientific decision

Last updated on October 13th, 2019 at 03:28 pm

Unless you’re a follower of the junk science presented by the pseudoscience shill, Joe Mercola and other crackpots, you probably didn’t think much of the artificial sweetener called aspartame (or by its more common trade name, Nutrasweet). You might have wondered if it was safe, but your skeptical mind probably rejected any safety issue not because most of the negative information came from bad sources–like Mercola.

Now that you’re here, reading this story, probably because you just read something about Pepsi and aspartame – because the giant soft drink bottler decided to remove it from their diet sodas. They did replace aspartame with–oh wait for it–two other artificial sweeteners. Obviously, Pepsi did it for marketing/public relations reasons, but the decision itself is based on bad information (on the internet, of course), rather than real science.

What is aspartame?

Aspartame is one of the most popular artificial sweeteners, approximately 200 times sweeter than common table sugar known as sucrose. Aspartame is a dipeptide of the natural amino acids Laspartic acid and Lphenylalanine.

Just to be clear, individual amino acids are exactly the same, no matter the source, and these two amino acids or peptides are consumed regularly with nearly any animal or plant protein. These two amino acids are nothing but simple “chemicals” that are constantly being consumed.

When aspartame is ingested, it is hydrolyzed (broken down by water into simpler molecules) into its constituent components: aspartate, phenylalanine and methanol, in an approximate 4:5:1 ratio.


No aspartame has been found in the bloodstream, since it is so quickly hydrolyzed in the gut, and only the constituent components are absorbed. To be absolutely clear, there is no difference between aspartic acid and phenylalanine that form aspartame than all “natural forms” of those amino acids that are contained in the proteins of food sources.

The safety of aspartame

Aspartame is one of the best-studied food additives ever. And it has been found to be safe, without reservation.

That’s why we have real science. The Scientific Opinion on the re-evaluation of aspartame (E 951) as a food additive (pdf), published by the European Food Safety Authority (EFSA), came to the following scientific consensus:

  • The amount of aspartame that is absorbed into the bloodstream is nonexistent in numerous human and animal studies. This supports the understanding that aspartame is hydrolyzed into its simple, and widely consumed, constituent components in the digestive tract.
  • Scientists have found no acute toxic effects of aspartame.
  • The available data did not indicate that aspartame had any genotoxic effect.
  • There were no aspartame-related increases in neoplasms and tumors in carcinogenecity studies.
  • They did recognize some studies indicated that aspartame should not be consumed in large quantities by pregnant women, not necessarily because of the aspartame itself, but possibly because of gastrointestinal disturbances and quality of overall diet. They established that the potentially harmful dose of aspartame is 1000 mg/kg/day, a few hundred cans of diet soda per day.
  • They noted that there was no epidemiological evidence for potential associations between consumption of aspartame and cancers.
  • A large prospective cohort study in Denmark found no consistent association between the consumption of artificially sweetened beverages (but not with aspartame specifically) during pregnancy and the diagnosis of asthma or allergic rhinitis in children.
  • Data did not support genotoxicity of the methanol metabolite of aspartame.

Those are the major points. The panel examined almost every negative claim about aspartame in detail, and reviewed all the scientific evidence–they found nothing. The EFSA came to its conclusion not by cherry-picking pro-aspertame research, but examining the body of evidence, and giving more weight to better designed studies and less weight (or even ignoring) badly designed ones. This is how science works.

Their conclusion–aspartame is safe. They did recommend consuming less than 40 mg/kg body weight/day (less than the FDA’s recommended 50 mg/kg/day), that’s still 17 cans of diet soda. To be honest, consuming that much diet soda might have other health issues about which to be concerned.

In other words, Pepsi and aspartame – perfectly safe.

Nevertheless, the trope that aspartame causes cancer, headaches, violence, weight gain, and some other big scary disorder. Of course, quacks like Joe Mercola and Natural News pushes these memes daily with constant pseudoscience.

Back to Pepsi

I know perfectly reasonable scientific skeptics will often joke that their daily cans of Diet Pepsi will probably make them grow a third eye or something. Setting aside the health fact that Diet Pepsi has a huge health benefit over regular Pepsi (that amount of sugar can lead to long-term metabolic effects), it’s hard to find even a tiny amount of evidence that aspartame has any negative health effect itself.

Pepsi decided to make this move despite there being no science supporting the moving. A Pepsi executive admitted as much:

While decades of studies show aspartame is safe, we recognize that consumer demand is evolving.

Look, I’m a good capitalist. If Pepsi wants to make a change in its Diet Pepsi formula, go for it. Obviously, this has worked out well in the past–whatever happened to New Coke? But making a decision based on bad science and bad information from a few scare websites? That’s just sad.

One other consequence of this change in Pepsi and aspartame – Mike Adams, the self described health ranger, is chortling over this decision about the “toxic sweetener.” He’ll be using this story as “proof” that he’s right for the next 10 years.

I’ll add my aspartame to my coffee every morning. I’ve been doing it for 30 years or so. It has done nothing to me–oh wait, that’s just an anecdote.

Michael Simpson
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