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4. Can aspartame affect human health?

  • 4.1 Can aspartame cause cancer or induce genetic damage?
  • 4.2 Can aspartame affect reproduction and development?
  • 4.3 Can aspartame produce neurological disorders?
  • 4.4 Can aspartame affect behaviour, cognition or mood?
  • 4.5 Does aspartame cause headaches?
  • 4.6 Does aspartame trigger epileptic seizures?
  • 4.7 Can aspartame cause other health effects?

4.1 Can aspartame cause cancer or induce genetic damage?

4.1.1 In laboratory studies:

  • Aspartame did not induce genetic mutations.
  • A study on mice showed no cancer effects. A first study on rats fed with very high doses of aspartame (1000 to 6000 mg/kg body weight per day) found a higher incidence of brain tumours. This study was contradicted by two subsequent ones. Therefore, it was concluded that aspartame does not cause brain cancer in laboratory animals.
  • Diketopiperazine does not cause cancer or genetic mutation in rats or mice.


4.1.2 In 1996, Olney published an article linking the consumption of aspartame and the occurrence of brain tumours in the United States, which has been criticized by a number of scientists. Subsequent studies did not find such a link. In France, the sale of aspartame did not increase the frequency of brain tumours. More...

4.2 Can aspartame affect reproduction and development?

In laboratory animal tests, no effects on reproduction and development was observed below 4.000 mg/kg body weight per day. At higher doses, some pups grew marginally slower and weighed slightly less than normal because they ate less. No other effects of aspartame and its breakdown products were observed on reproduction and development (including neurodevelopment). More...

4.3 Can aspartame produce neurological disorders?

Following the marketing of aspartame, some consumers complained of neurological or behavioural effects. These complaints received special consideration because some experiments in rats had shown that very high doses of aspartame (1000 mg/kg body weight per day) could alter the concentrations of some important substances (neurotransmitters) in the central nervous system. However, it appears that these effects on neurotransmitters are not consistent and could not be reproduced in later studies.

About 10% of aspartame breaks down into methanol, which is known to be toxic. However, toxic effects on vision and the central nervous system only occur at doses of methanol 100 times higher than could be produced from the amount of aspartame in one litre of "diet" soft drink. More...

4.4 Can aspartame affect behaviour, cognition or mood?

Some years ago, it was suggested that aspartame could have effects on human behaviour and cognition. However, studies on laboratory animals showed no adverse effects on behaviour and cognition, even at very high doses (up to 2000 mg/kg body weight per day).

Also, studies in healthy adults and children and in people heterozygous for phenylketonuria (PKU) disease failed to show effects of aspartame on behaviour, mood or learning. But a study suggested that aspartame increased the frequency and severity of adverse effects in depressed individuals; this study must however be taken with caution as there were criticisms regarding the authors’ interpretation and because too few subjects were evaluated. More...

4.5 Does aspartame cause headaches?

Headaches are one of the most commonly reported symptoms. Three studies on humans indicate a possible association between aspartame intake and headaches. However, it is not possible to draw conclusions. A more recent study in a controlled environment on individuals complaining of aspartame-related headaches concluded that aspartame was no more likely to trigger headaches than placebo. More...

4.6 Does aspartame trigger epileptic seizures?

Some websites report testimonies of people who identify aspartame as the cause of their health problems and epileptic seizures. A few studies have linked the consumption of large amounts of aspartame and the triggering of epileptic seizures. They suggest that aspartame could cause seizures by affecting the synthesis of neurotransmitters in the brain. Also, some animal studies indicate that aspartame reduces the threshold of sensitivity to chemically induced seizures.

Another study reported that aspartame could increase the duration of certain types of epileptic seizure in children. Effects of phenylalanine, aspartic acid and methanol on seizures have been reported, but under unusual conditions, such as high doses, particular sensitivities or rare types of seizures. This relationship has been refuted by a large number of scientists, who base their opinions on many animals and humans studies.

The Epilepsy Institute in the USA has also concluded that aspartame is not the cause of epileptic seizures. More...

4.7 Can aspartame cause other health effects?

Some individuals have attributed their allergic reactions to aspartame. However, two studies on such individuals indicated that their allergies were no more likely to be caused by aspartame than by placebo.

Other studies focusing on the effects of aspartame on hunger and food intake, reported that aspartame did not cause an increase in calorie consumption or body weight. More...

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