Skip to content

The truth about the side effects of aspartame

Die Wahrheit über die Nebenwirkungen von Aspartam

The aspartame controversy

Aspartame is one of the most popular artificial sweeteners on the market. There is a very good chance that you, or someone you know, has had an aspartame-containing diet drink in the last 24 hours. According to a study by the U.S. Centers for Disease Control and Prevention, one-fifth of all Americans consumed diet drinks every day in 2010 (1).

Although this sweetener continues to enjoy great popularity, it has become an increasingly controversial compound in recent years. Many opponents of aspartame claim that this sweetener is bad for your health. There are also claims of long-term damage from prolonged aspartame consumption.

Unfortunately, despite extensive research, there is still no consensus on whether aspartame is actually harmful.

What is aspartame?

Aspartame is also marketed under the brand names NutraSweet and Equal. This sweetener is also used in many processed products sold as diet foods.

The ingredients that make up aspartame are aspartic acid and phenylalanine. Both of these compounds are naturally occurring amino acids. Aspartic acid is produced by the human body and phenylalanine is an essential amino acid that we consume in our diet.

When the body processes aspartame, some of it is broken down into methanol. The consumption of fruit, fruit juice, fermented drinks and some vegetables can also result in either a direct intake or production of methanol. In 2014, aspartame was the largest source of methanol in the American diet (2).

Methanol is toxic in larger amounts, but even smaller amounts can be of concern when combined with free methanol, which increases absorption. Free methanol is present in some foods and is also produced when aspartame is heated. Regularly consumed free methanol can become a problem as it breaks down into formaldehyde, which is a known carcinogen.

However, the Food Standards Agency in the UK has stated that even in children who consume large amounts of aspartame, the maximum non-critical amount of methanol is not reached. Furthermore, it has been pointed out that while fruit and vegetables are known for their health benefits, methanol intake from these sources is not a high priority for research.

As reported by Dr. Alan Gaby, in the Alternative Medicine Review in 2007, aspartame found in commercial products or heated beverages could be a trigger for seizures and should therefore be considered in cases of difficult seizure management (3).

Aspartame approval

A number of authorities and health organizations have spoken positively about the safety of aspartame and have approved this sweetener. These include, among others:

  • U.S. Food and Drug Administration (FDA)
  • United Nations Food and Agriculture Organization
  • World Health Organization
  • American Heart Association
  • American Dietetic Association

In 2013, the European Food Safety Authority (EFSA) conducted a review of over 600 data sets from aspartame studies (4). No reason was found to withdraw aspartame from the market. The review reported no safety concerns at normal or increased intakes.

On the other hand, artificial sweeteners have a long history of controversy. Aspartame was developed at the same time that the U.S. Food and Drug Administration (FDA) removed the artificial sweeteners cyclamate and saccharin from the market (5). Laboratory studies had shown that massive doses of these two compounds caused cancer and other diseases in laboratory animals.

While aspartame has been approved by the U.S. Food and Drug Administration, the consumer advocacy organization Centre for Science in the Public Interest has cited numerous studies suggesting problems with this sweetener, including a study by the Harvard School of Public Health (6).

Products with aspartame

Whenever a product is labeled "sugar-free", it usually means that it contains an artificial sweetener instead of sugar. Although not all sugar-free products contain aspartame, aspartame is one of the most popular sweeteners. It is found in many packaged foods.

Some examples of aspartame-containing products include:

  • Diet drink
  • Sugar-free ice cream
  • Sugar-free chewing gum
  • Yogurt
  • Sugar-free sweets

The use of other sweeteners can help to reduce aspartame intake. However, if you want to avoid aspartame completely, you need to look at food labels.

Side effects of aspartame

According to the American Cancer Society, aspartame is about 200 times sweeter than sugar, which means that only a very small amount is needed to give food and drinks a sweet taste (7). The acceptable daily intake according to the FDA and EFSA is

  • FDA: 50 milligrams per kilogram of body weight
  • EFSA: 40 milligrams per kilogram of body weight

A can of an aspartame-sweetened soft drink contains about 185 milligrams of aspartame. A person weighing 70 kilograms would therefore have to consume more than 15 or 18 cans of such a drink per day to exceed these amounts.

People who suffer from a metabolic disorder known as phenylketonuria, on the other hand, should not consume aspartame at all. People taking medication to treat schizophrenia should also refrain from consuming aspartame.


People who suffer from phenylketonuria have high levels of phenylalanine in their blood. Phenylalanine is an essential amino acid that is found in protein sources such as meat, fish, eggs and dairy products. Phenylalanine is also one of the two components of aspartame.

People who suffer from this metabolic disorder are unable to metabolize phenylalanine correctly. If you suffer from this disease, aspartame has a highly toxic effect.

Tardive dyskinesia

Tardive dyskinesia is believed to be a side effect of some medications used to treat schizophrenia. The phenylalanine in aspartame may increase the uncontrolled muscle movements associated with tardive dyskinesia.


Anti-aspartame activists claim that there is a link between aspartame and a variety of conditions including the following:

  • Cancer
  • seizures
  • headaches
  • depression
  • Attention Deficit Hyperactivity Disorder (ADHD)
  • dizziness
  • Weight gain
  • Birth defects
  • lupus
  • Alzheimer's disease
  • Multiple sclerosis

Numerous studies have attempted to establish or disprove a link between aspartame and these conditions, but so far these studies have produced inconsistent results. Some sources report increased risks, symptoms or exacerbation of certain conditions, while others have found no negative effects of aspartame (8).

The effects of aspartame on diabetes and weight loss

When it comes to diabetes and weight loss, one of the first steps people take is to eliminate empty calories from their diet. This often includes sugar.

Aspartame has both benefits and drawbacks when it comes to diabetes and obesity. The Mayo Clinic has stated that artificial sweeteners are generally beneficial for diabetics (9). However, this does not necessarily mean that aspartame is the best sweetener of choice.

Artificial sweeteners can also help support weight loss efforts, but this is generally only the case if you have consumed a lot of sugary products before starting your weight loss efforts. Switching from sugary products to products with artificial sweeteners could also reduce the risk of tooth decay.

According to one study, rats fed aspartame had a lower total body mass (10). One caveat to this study is that these rats had both more gut bacteria and increased blood sugar levels. This increase in blood glucose levels was also associated with insulin resistance.

The scientific evidence on how aspartame and other sweeteners affect these and other diseases is far from conclusive.

Natural alternatives to aspartame

The controversy surrounding aspartame continues. Available scientific data suggests no long-term negative side effects, but the final word has not yet been spoken and research is ongoing. Before you go back to using sugar (which is high in calories but has no real nutritional value), you may want to consider natural alternatives to aspartame, which include the following:

  • Honey
  • maple syrup
  • agave nectar
  • fruit juices
  • Stevia leaves

But even if these products are more natural than artificial sweeteners such as aspartame, you should still only use them in limited quantities. Just like sugar, natural alternatives to aspartame can provide a lot of calories with little or no nutritional value.

The future of aspartame

Public concerns about aspartame remain. Scientific research has found no consistent evidence of harmful effects, making aspartame acceptable for daily use.

Due to the intense criticism, many people have taken steps to avoid artificial sweeteners altogether, but many others who are consciously watching their sugar intake continue to use artificial sweeteners.

When it comes to aspartame, just as with sugar and other sweeteners, the best course of action is probably to use this sweetener in limited amounts.




Previous article The ketogenic diet A detailed beginner's guide to the ketogenic diet
Next article 8 natural alternatives to sugar