A new study of artificial sweeteners in place of real sugar seems to show a link to cancer. Of course, this starts a new set of claims that these sweeteners are dangerous and should be avoided.
But your obstreperous feathered avian or non-avian dinosaur has a different take. I don’t think the research is all that conclusive, and I’m not even sure it tells us anything about the safety of artificial sweeteners. I have a long tradition of being skeptical of research into artificial sweeteners.
As I like doing, let’s take a look at this new article and determine if it presents anything linking artificial sweeteners to cancer.
Artificial sweeteners and cancer paper
Researchers Charlotte Debras of the Sorbonne Paris Nord University in France and colleagues published their paper in PLoS Medicine on 24 March 2022. The researchers followed 102,865 adults from the French population-based cohort NutriNet-Santé (2009–2021) with a median follow-up time of 7.8 years. Dietary intakes and consumption of sweeteners were obtained by repeated 24-hour dietary records including brand names of industrial products.
A total of 3,358 incident cancer cases were diagnosed during follow-ups. The mean age at diagnosis was 59.5, and the most common cancer types were obesity-related (2,023 cases), breast (982 cases), and prostate (403 cases).
The cutoffs between “high consumers” and “low consumers” were sex-specific — 17.44 mg/day in men and 19.00 mg/day in women for total artificial sweeteners, 14.45 mg/day in men and 15.39 mg/day in women for aspartame, 5.06 mg/day in men and 5.50 mg/day in women for acesulfame potassium and 3.46 mg/day in men and 3.43 mg/day in women for sucralose.
Here are some of the key results:
- “High consumers” of artificial sweeteners had a slightly higher risk of developing obesity-related cancers, including colorectal, stomach, liver, mouth, pharynx, larynx, esophageal, breast (hazard ratio = 1.13 or 13% increased risk)
- Aspartame alone was linked with a 15% higher risk for obesity-related cancers (HR = 1.15), and a 22% higher risk for developing breast cancer (HR = 1.22).
- Acesulfame potassium showed a 13% higher risk for obesity-related cancers (HR = 1.13).
- Sucralose consumption at any level was not linked to any increased cancer risk.
- People who consumed artificial sweeteners tended to be women, younger, smokers, less physically active, more educated, and more likely to have prevalent diabetes compared with those who avoided artificial sweeteners.
So where do I take issue with this article? Let me list the ways:
- Large studies and reviews have rejected any link between aspartame and cancer. There appear to be more published articles that have not shown a link between aspartame and cancer than show a link.
- The European Food Safety Authority and other reviews reject any link between acesulfame potassium and cancer.
- Obesity is strongly linked to cancer. However, it is not clear whether the researchers attempted to establish whether those who consumed higher levels of artificial sweeteners had lost weight and reduced their risk of cancer. Or whether participants consumed other foods and engaged in other behaviors that correlated with increased sweetener consumption that could have increased the risk of cancer. The authors tried to eliminate some confounders, but they even admitted that they were unsure what other confounders existed. For example, individuals who consume more artificial sweeteners may consume other foods that may increase the risk of cancer.
- Artificial sweeteners are found in many foods that may escape the notice of the participants. Sugar-free candies and gums, yogurt, and many other foods include artificial sweeteners. Individuals who are obese may select these foods, but because they weren’t putting packets of the sweetener into their coffee, it may not be included in the dosage.
- One of the most important factors for determining causality is biological plausibility. Aspartame is simply two amino acids connected to one another. I find it implausible that amino acids can cause cancer.
- Acesulfame potassium is almost always used with other sweeteners. I am mystified as to how the researchers could determine what the actual consumption of it would be.
- I am troubled by selection bias in this research. The average time followed was only 7.8 years, and the somewhat short period to link an environmental issue like the consumption of these sweeteners with the diagnosis of cancer. The appearance of cancer could be that the researchers were selecting a group that is much more at risk of cancer, causing it to show up rather quickly.
- In this study, individuals who consumed artificial sweeteners were smokers, less physically active, and diabetic. All of those three are risk factors for cancer. I know the authors tried to adjust for these confounders, but as long as the group that consumed artificial sweeteners exhibited other risk factors for cancer, it remains difficult to tease out which risk factor was most important.
- Remember, and I cannot stop stating this, correlation does not mean causation. It is not possible to determine whether high levels of artificial sweetener intake cause cancer, or whether individuals with cancer consume excessively high levels of artificial sweeteners.
- The study included only individuals in France. This is a huge selection bias issue, since French cultural differences may account for the results.
- Only about 3.3% of the participants were diagnosed with cancer during the follow up so the relative risks appear to be modest at best.
Summary
The study by Debras and colleagues was well done. But I don’t think the results are convincing reasons to avoid artificial sweeteners to avoid cancer.
Let’s just take a look at a simple case — obesity is strongly linked to many cancers, so if you can reduce or maintain your weight by consuming artificial sweeteners rather than sugar-laden foods, the sweetener may reduce your risk of cancer. Unfortunately, this study wasn’t powered to give us this information.
I’m sure some of you will say “drink water, not artificial anything,” which is fine, but for people struggling to maintain their weight, artificial sweeteners are the first step.
On the other hand, if you’re one of those people who are believers in the precautionary principle, you’ll think this is good enough to avoid them. Well, I’d strongly disagree because I don’t think this research is powerful enough to go either way on the topic of these sweeteners. Of course, you might want to consider sucralose, since this study showed no link to cancer.
I have my own bias — I find nutritional studies to be nearly worthless in trying to link some food or food additive to increasing or reducing cancer risk.
If you hate artificial sweeteners, you’ll probably buy into the cancer risk. Or you can look at this scientifically and yawn — it doesn’t tell us much about cancer risks from artificial sweeteners.
Citations
- Debras C, Chazelas E, Srour B, Druesne-Pecollo N, Esseddik Y, Szabo de Edelenyi F, Agaësse C, De Sa A, Lutchia R, Gigandet S, Huybrechts I, Julia C, Kesse-Guyot E, Allès B, Andreeva VA, Galan P, Hercberg S, Deschasaux-Tanguy M, Touvier M. Artificial sweeteners and cancer risk: Results from the NutriNet-Santé population-based cohort study. PLoS Med. 2022 Mar 24;19(3):e1003950. doi: 10.1371/journal.pmed.1003950. PMID: 35324894; PMCID: PMC8946744.
- Kirkland D, Gatehouse D. “Aspartame: A review of genotoxicity data“. Food Chem Toxicol. 2015 Oct;84:161-8. doi: 10.1016/j.fct.2015.08.021. Epub 2015 Aug 28. PMID: 26321723.
- Marinovich M, Galli CL, Bosetti C, Gallus S, La Vecchia C. Aspartame, low-calorie sweeteners and disease: regulatory safety and epidemiological issues. Food Chem Toxicol. 2013 Oct;60:109-15. doi: 10.1016/j.fct.2013.07.040. Epub 2013 Jul 23. PMID: 23891579.
