Aspartame: the rumors, the side-effects and the answers

Find out if this sweetener truly deserves its bad reputation or not


Aspartame is the most widely used artificial sweetener in the world. It is mainly employed in package food labeled for “dieting” as it was the first approved low-calorie sweetener back in 1981.

Nevertheless and despite its approval and common usage, it is under debate as more side-effects come into light or are hinted at.

Is aspartame bad for you?

Although several studies have been conducted already to assess its safety, a conclusion is yet to be reached.

Aspartame is one of the largest sources of methanol, which is produced as the body processes the sweetener. If the intake is small and occasional, there are no indications that it could be dangerous even if it’s still not recommended. However, according to three different researches from 2006, 2007 and 2010, its frequent consumption and in big quantities produces formaldehyde, a carcinogen. 

Following the first research in 2006, the US National Cancer Institute also performed a study to confirm the results but it did not find any indication that this sweetener increases the risk of cancer. Later, in 2015, a research project by the Food Standards Agency in the UK concluded that a moderated use of aspartame did not present any side-effects or dangers that would require reviewing its approval.

What are its side-effects?

aspartame side-effects

This sweetener side-effects are directly related to the ongoing research about it. That is to say that, aside from the toxicity risk for people with phenylketonuria, there aren’t any other proved side-effects of this sweetener.

As previously mentioned, research hasn’t so far provided irrefutable proof of its risks. The food control agencies, the FDA in the US and the European Food Safety Authority (EFSA), have not established any side-effects as long as the quantities are kept to the recommended daily intake.

It can be toxic to people with phenylketonuria (PKU)

Phenylketonuria is a disorder that increases the level of phenylalanine in the blood, as the body is unable to break it down. This is an essential amino acid obtained through a normal diet, particularly out of the intake of protein-rich foods.

However, phenylalanine is also one of the main components of aspartame. Therefore, its consumption can prove toxic and lead to brain damage.

Claimed side-effects

There are several side-effects attributed to the consumption of this sweetener that so far lack any solid scientific background or proof. These include:

  • Depression
  • Weight gain
  • Birth defects
  • Dizziness
  • Seizures
  • Cancer
  • Lupus
  • Attention deficit hyperactivity disorder (ADHD)
  • Headaches
  • Vision problems
  • Confusion
  • Memory loss

Aspartame poisoning

aspartame poisoning

Aspartame poisoning is hard to occur, as long as you don’t suffer from phenylketonuria.

The EFSA estimates that the average daily intake shouldn’t surpass the 40mg/kg body weight. In practice, this means that a person would have to drink approximately 12 cans of a diet soft drink daily to surpass it, assuming the manufacturer uses the maximum limit allowed of this sweetener in its drinks.

On the other hand, the FDA has deemed aspartame safe at an average daily intake of 50mg/kg body weight.

Still, there is no solid proof of any side-effects past these limits. However, these values serve as a reference since negative research tends to use as large or larger amounts in their experiments.

Sucralose vs aspartame

Sucralose is a modified form of sugar 400 to 700 times sweeter, but with no calories. It is claimed to be completely safe for consumption as it has no effect over the insulin levels for the majority of the people.

However, just as with aspartame, its use is not free of controversy. There are some studies already suggesting it can affect the blood sugar levels and that it damages for the good bacteria present in the gut. Its resistance to heat modifications is also being questioned as there is the possibility it can break down into toxic components.

Furthermore, sucralose and aspartame are not a complete substitute of each other as they change the food flavor in a slightly different way.

To learn more about the difference between the two, check the video below to learn about how PepsiCo changed its formulas to substitute aspartame for sucralose and the changes were pushed back by consumers.