Will Aspartame Kill You?

I do confess to having a bit of a conflict of interest here. I drink rather a lot of Diet Coke, a can or two per day, and so I seriously have to examine my thinking and ask if confirmation bias is kicking in when writing to assure you that Aspartame is totally safe.

Is such an assurance warranted or are there serious healthy concerns?

let’s see.

The Discovery

The accidental discovery of this artificial sweetener is something that causes me to pause with a “Wait, he did what!” retort.

The backstory here is that in 1965 chemist James M. Schlatter was working on generating a tetrapeptide of the hormone gastrin. At that time it was part of some research he was doing into an anti-ulcer drug candidate, and so as one of the intermediate steps he synthesized aspartame.[1]. The discovery happened when he attempted to pick up some paper by licking his finger and discovered a sweet taste. It was the Aspartame that had contaminated his hands.

My immediate thought on hearing about this is to seriously wonder how a guy who was randomly licking his unwashed fingers in a chemistry lab after contaminating them managed to not die an early and rather sudden death. Seriously … who actually does this?

Dire Warnings about the evils of Aspartame

It is popular for some to advise you that Aspartame is the “Most Dangerous Substance on the Market“. That last link is one of the top 10 you get when you google the word Aspartame, and so is clearly a popular view. The problem there is that while that source looks and feels like a credible reliable source, it is not. As explained on his Wikipedia page which is well-referenced, Dr Mercola is a well-known alternative medicine practitioner with a highly dubious reputation. He is highly criticised for the promotion of stuff that does not actually work at all, and the dismissal of the evidence based medicine that does really work …

On his website mercola.com, Mercola and colleagues advocate a number of unproven alternative health notions including homeopathy, while promoting anti-vaccine positions.

Mercola has been criticized by business, regulatory, medical, and scientific communities. A 2006 BusinessWeek editorial stated his marketing practices relied on “slick promotion, clever use of information, and scare tactics.”[3] In 2005, 2006, and 2011, the U.S. Food and Drug Administration warned Mercola and his company to stop making illegal claims regarding his products’ ability to detect, prevent, and treat disease.[6] The medical watchdog site Quackwatch has criticized Mercola for making “unsubstantiated claims [that] clash with those of leading medical and public health organizations and many unsubstantiated recommendations for dietary supplements.”[6]

So who can you trust?

There are of course many scientific studies that do verify the safety of this artificial sweetener. Beyond that we also have credible reliable non-commercial subject matter experts advising that it really is safe. For example here are some organisations that strive review all the literature and then issue the best possible consumer advise possible.

The UK’s National Health Service – The truth about aspartame

Note that the NHS does not simply tell you “It is fine, trust us”, but instead they give you the links to the actual evidence so that you can go and check it all yourself if you are inclined to do so …

Aspartame has been subject to more scare stories than any other sweetener, ranging from allergies and premature births to liver damage and cancer….

Aspartame has been extremely controversial since its approval for use by several European countries in the 1980s. A 1996 report suggested a link between aspartame and an increase in the number of diagnosed brain tumours. However, the study had very little scientific basis and later studies showed that aspartame was in fact safe to consume.

The European Ramazzini Foundation of Oncology and Environmental Sciences published several long-term studies in 2006 and 2007 linking the consumption of aspartame with an increase in cancers – namely lymphomas and leukaemias – in rats.

Following these studies, the US National Cancer Institute conducted a study of nearly half a million people, comparing those who consumed drinks containing aspartame with those who did not. Results of the 2006 study (PDF, 87kb) found aspartame did not increase the risk of leukaemia, lymphoma or brain cancer.

In 2013 the European Food Safety Authority (EFSA) conducted a comprehensive review of the evidence (PDF, 2.25Mb) and concluded that aspartame was safe for human consumption, including pregnant women and children.

The American Cancer Society – Aspartame

Rumors claiming that aspartame causes a number of health problems, including cancer, have been around for many years. Many of these continue to circulate on the Internet …

In the body, aspartame is broken down into phenylalanine, aspartic acid, and methanol. Methanol can be toxic in high amounts, but the amounts that result from the breakdown of aspartame is lower than with many “natural” foods. For example, drinking a liter of diet soda would lead to consumption of 55 milligrams (mg) of methanol, as compared to as much as 680 mg of methanol from a liter of fruit juice …

Many studies have looked for health effects in lab animals fed aspartame, often in doses higher than 4,000 mg/kg per day over their lifetimes. These studies have not found any health problems that are consistently linked with aspartame.


The US Food and Drug Administration (FDA) …

Considering results from the large number of studies on aspartame’s safety, including five previously conducted negative chronic carcinogenicity studies, a recently reported large epidemiology study with negative associations between the use of aspartame and the occurrence of tumors, and negative findings from a series of three transgenic mouse assays, FDA finds no reason to alter its previous conclusion that aspartame is safe as a general purpose sweetener in food.

The European Food Safety Authority (EFSA) …

Overall, the Panel concluded, on the basis of all the evidence currently available… that there is no indication of any genotoxic or carcinogenic potential of aspartame and that there is no reason to revise the previously established ADI for aspartame of 40 mg/kg [body weight].

Some Caution for Some is Appropriate

In a manner similar to many other food products, one size does not fit all. Some have to take care about the intake of specific specific things, for example a peanut allegory, or gluten intolerance. A very small number, have a rare genetic disorder in which they can’t break down phenylalanine, an amino acid found in many foods. This is one of the compounds within Aspartame, so those with this condition need to be cautious regarding their consumption of aspartame. Having this condition will not be a surprise, those with it will have already have had it diagnosed via a standard screening at birth and will perhaps also be aware of a parent who has this condition.

Like many other appropriate warnings, products containing Aspartame often contain the scary sounding label – “Phenylketonurics: contains phenylalanine.”. If you do not know what that means, then it is not a warning for you. It is a label that is akin to the more common warning of “Caution, this product may contain nuts”, that most of us can happily ignore, but is of extreme importance to anybody at risk of a life threatening anaphylactic shock reaction to nuts.

Bottom Line

Nobody, expect perhaps medical quacks, are sounding the alarm about aspartame.

If you are still not sure, then let me give you one more reference. FDA officials describe aspartame as …

“one of the most thoroughly tested and studied food additives the agency has ever approved”

… and its safety as …

“clear cut”

One last rather obvious thought – consumption is not mandatory, so if you really don’t like it then don’t consume it. If however your concern is health related, then there is no evidence of any health related issues, literally hundreds of studies confirm this. When consuming it, then to answer the initial opening question … no, it will not kill you.


  1. Mazur, Robert H. (1974). “Aspartic acid-based sweeteners”. In Inglett, George E. Symposium: sweeteners. Westport, CT: AVI Publishing. pp. 159–163
  2. Wikipedia Page on Aspartame
  3. The UK’s National Health Service guidance – The truth about aspartame
  4. The American Cancer Societies guidance – Aspartame

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