Are sweeteners killing you?

There's a number of chemicals we use to make drinks taste sweet.

The reason people have a misconception that “sweeteners cause cancer” is because back in 1969, a sweetener called Cyclamate caused bladder cancer in rats, so it was banned.

Nowadays you will only encounter sweeteners that the European Food safety authority have deemed safe:

- Aspartame (fizzy drinks)

- Saccharin (fizzy drinks)

- Sorbitol (naturally occurring, prunes and cherries)

- Sucralose (low fat products, ‘healthier’ drinks)

- Stevia (naturally occurring, from a leaf)

- Xylitol (in toothpaste)

- Acesulfame K (added to sucralose/aspartame to enhance sweetness)

Note: Almost all these sweeteners are used in a combination in chewing gum.

  • sweeteners don’t stimulate the same parts of the brain as sugar resulting in a lessened feeling of fullness, resulting in eating more
    Click on image for more info

Aspartame is usually in your classic “diet” drinks, and most often comes under fire from the media

In 1996 there was a study which linked aspartame to brain cancer in rats

In 2007 a study linked aspartame to leukaemia and lymphoma in rats

The important thing about scientific studies is that they’re trying to find a link, just like if you looked at how many cars you saw in a day and how happy you felt on that day, you’d probably find a link, but that doesn’t mean that cars are causing you happiness. This point is emphasised if you carried out this test on rats not humans.

  • In 1996 there was a study which linked aspartame to brain cancer in rats
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So in scientific literature we ‘review’ all the relevant studies to decide if there is a link, and when this was done in 2013, aspartame was deemed safe for human consumption.

An important study in 2004 discredited the others by finding the amounts needed to cause a change to brain chemical composition, which came to be 1g. So, a recommended daily allowance was drawn up to be 40mg per kilogram of your bodyweight, which for an average person is about 10 cans of ‘diet’ drinks a day.

A brand new study in 2017 has now linked aspartame to Alzheimer’s, Dementia and strokes. The percentage increase in risk was very small and some important information about the participants was not accounted for (e.g. patient having diabetes). As you can imagine the scientific community is cynical.

But as you could imagine, if you took 100 people with relativley similar lifestyle choices, you may find that a number of them naturally end up suffering from a stroke or dementia.

  • New study in 2017 has now linked aspartame to Alzheimer’s, Dementia and strokes
    Click on image for more info

The healthiest thing to drink is water. If you are still worried about aspartame intake, sucralose alternatives are available. Artificial sweeteners are useful for controlling dietary sugar intake but shouldn’t be consumed in excess, but as part of a balanced diet.


Sam Fitzpatrick Final Year Medical Student, Cardiff University.

Milad Rouf Final Year Medical Student, Cardiff University.

National Cancer institute:

Olney, J., Farber, N., Spitznagel, E. and Robins, L. 1996. Increasing Brain Tumor Rates: Is There a Link to Aspartame?. Journal of Neuropathology & Experimental Neurology 55(11), pp. 1115-1123.

Lim, U. 2006. Consumption of Aspartame-Containing Beverages and Incidence of Hematopoietic and Brain Malignancies. Cancer Epidemiology Biomarkers & Prevention 15(9), pp. 1654-1659.

EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) 2013. Scientific Opinion on the re-evaluation of aspartame (E 951) as a food additive. EFSA 10.2903/j.efsa.2013.3496.

Lean, M. 2004. Aspartame and its effects on health. BMJ 329(7469), pp. 755-756.

Pase, M., Himali, J., Beiser, A., Aparicio, H., Satizabal, C., Vasan, R. and Seshadri, S. et al. 2017. Sugar- and Artificially Sweetened Beverages and the Risks of Incident Stroke and Dementia. Stroke 48(5), pp. 1139-1146.

Behind the headlines, NHS choices. 2017. Reported link between diet drinks and dementia and stroke is weak. Pubmed health