Does aspartame cause cancer? What do the scientific studies say?

You may have noticed that the International Agency for Research on Cancer (IARC), which is part of the WorldHealth Organisation (WHO), recently listed the artificial sweetener aspartame as a potential carcinogen. This decision has caused a huge outcry in the media and, of course, in society. Does this mean that we should start avoiding artificial sweeteners and instead buy only products containing regular sugar?

In today's article we will look at the issue of aspartame in detail. In addition to discussing the recent inclusion of this substance on the list of potential carcinogens, we will also look at how aspartamein the human body, and answer the question of whether it is really better to choose regular sugar over this sweetener.

What does 'potential carcinogen' mean?

First of all, we need to look at what has actually happened recently. The media is full of headlines about aspartame causing cancer, but the recent IARC decision means something slightly different. This agency is investigating substances that could theoretically be carcinogenic. It then divides them into four categories: proven carcinogen, probable carcinogen, potential carcinogen and unclassified substance. It is important to note that the IARC is not a regulatory body, so it cannot ban individual substances. The above categories serve only as warnings or recommendations, while the authorities that can actually regulate the use of individualsubstances in the food industry do not automatically adopt the IARC's conclusions and carry out their own research and testing to restrict these substances.

In practical terms, this means that the use of aspartame is allowed to the same extent as before. The European Food Safety Authority still considers aspartame to be safe at recommended doses. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has also confirmed its previous opinion that the recommended maximum daily intake of aspartame is 40 mg per kilogram of human weight. At first sight it may seem strange that while one body designates a given amount ofas a potential carcinogen, other authorities still allow its use. However, in the overall context, this is not strange at all.

The different categories of carcinogens according to the IARC

As already mentioned, the IARC divides carcinogens into four groups. However, it is important to note that these carcinogens may not only be food substances, but may also be a variety of activities. In the group of confirmed carcinogens, therefore, we find, for example, smoking, alcoholic beverages, industrially processed meat or, for example, the occupation of firefighter. The second group marked as probable carcinogens includes working night shifts, drinking beverages hotter than 65℃ or eating red meat. All of these things are therefore more dangerous than aspartame in terms of cancer risk, according to the IARC.

In the group of potential carcinogens, besides aspartame, we also find aloe vera, traditional Asian pickled vegetables, working in a printing press or carpentry and joinery. A closer look at the different categories of carcinogens according to the IARC shows that many of them we would never have thought of as dangerous. Similarly, we are not at all surprised that we can buy pickled vegetables or a drink with aloe vera in the shops. But how is it possible that these substances or activities have made it onto the list of carcinogens?

The IARC's evaluation of carcinogens takes into account any indication that a substance (or activity) might pose a risk. Often, a minimal association with a given drug is sufficient for inclusion in each group.with a particular risk, and there may be no causal link between the substance and cancer risk at all. Simply put, the IARC has a very low standard for what it considers to be sufficient reason to classify substances and activities as carcinogens. However, this is due to the nature of this agency. Its role is not to ban anything, but only to warn of possible risks.

Problems with some scientific studies

Although the inclusion of aspartame in the category of potential carcinogens may obviously mean nothing, many people consider this sweetener to be dangerous. This is mainly due to the large number of studies that have become very popular and are also referred to by many media outlets. However, these studies very often have several fundamental flaws which make it necessary to take their results with a pinch of salt. An example is the 2022 study that found that sweeteners such as aspartame, acesulfame K and sucralose are associated with a higher risk of cancer. The shortcomings of this study have been very well discussed by the Institute of Modern Nutrition, so we will limit ourselves to just some of the main points at this point.

Although this study has often been cited in the media as evidence that aspartame causes cancer, no such conclusion can be drawn with certainty from similar studies. The fact that two phenomena occur side by side does not automatically mean that one causes the other (correlation is not causation). Another major problem with this study was the way in which the researchers recorded the eating habits of the test subjects. This is because they relied only on questionnaires filled out by the people involved. The biggest paradox, however, is that the group of people who consumed the most artificial sweeteners actually did not have the highest risk of cancer, according to the study.

Yet there are countless studies with similar problems. They often leave out other important factors, such as the individual's lifestyle.studies, reverse causality is ignored, studies are often only short-term, and so on. However, these problems are not unique to aspartame, but apply to scientific studies in general. Therefore, when evaluating studies, it is always necessary to consider not only the conclusion itself, but also all variables.

Is aspartame something to be afraid of?

So what should one take away from all this? Is there a reason to avoid aspartame and similar sweeteners? At present, there are no studies or scientific evidence to confirm thatthat the use of aspartame in the permitted amounts can harm a person. All the studies that have reached similar conclusions have suffered from some serious flaw (see previous paragraph). On the other hand, there is a meta-analysis of 68 studies carried out, which shows that none of the studies carried out proved thatthat the use of artificial sweeteners is directly related to an increased risk of cancer.

But if aspartame still doesn't appeal to you, you might be interested in a 2013 study that looked at the 50 most common ingredients you might encounter in an ordinary cookbook. Researchers found that a full 80% of these ingredients can be found in a scientific study that says the food poses a cancer risk. This is simply a consequence of the way studies like this are conducted. If we were to follow every study that suggests that a substance could theoretically bedangerous, we'd probably have to live on pure water alone (until someone started doing too much research on that too).

Most important of all, don't panic unnecessarily. The truth is that we come into contact with far worse substances every day that are far more dangerous to our health than aspartame could theoretically be. The average Czech drank over 160 litres of alcohol in 2021. As we already know, alcohol has long been a proven carcinogen. But it doesn't seem to worry anyone too much. So before we start demonising substances like aspartame and other artificial sweeteners, we should first of all turn our attention toto alcohol, tobacco and the extremely poor eating habits of our population.

How does the human body process aspartame?

Finally, let's take a brief look at how the human body processes the sweetener aspartame. In the body, this substance is broken down into aspartic acid, phenylalanine and methanol. Methanol, in particular, evokes mixed feelings in people because they associate it with the methanol scandal of 2012. However, the reality is that after drinking one can of aspartame-sweetened beverage, you take into your body about one-third the amount of methanol compared to thosem if you drank one glass of orange juice (see the excellent article on the Institute of Modern Nutrition website for more details). Yet no one has thought of banning the sale of orange juice.

As a result of the large number of negative reports in the media and often largely misleadingscientific studies, aspartame is perceived in society as something very dangerous and bad. The reality, however, is that aspartame is no worse off health-wise than other foods that we consume on a daily basis. On the contrary, some much worse substances are perceived by mainstream society as perfectly normal and health almost harmless, even though their real health effects are far worse (this is particularly true of alcohol). Of course, here too, nothing should be exaggerated. Of course, excessive consumption of food and drink with artificial sweeteners is also undesirable and can cause health problems.

Final summary

The recent decision by the International Agency for Research on Cancer needs to be seen in the overall context and not automatically panic. The European Food Safety Authority continues to classify aspartame at the permitted dosageaspartame is a safe substance and there is therefore no reason to be unduly concerned about its use. If you'd still rather avoid aspartame, don't overlook our comparison of the best sweetener-free proteins.

If you have any questions about this topic, we'd be happy to hear from you in the comments below.