Updated 15 February 2017

The aspartame controversy

The safety of the artificial sweetener, aspartame, is hot news. Some reports have even been saying that it could cause cancer. But is it really dangerous? DietDoc investigates.

Readers regularly ask me if it's safe to use aspartame, or they send me excerpts from scary articles published in the media or on the internet linking aspartame to every health problem known to mankind.

According to anti-aspartame websites and sensational stories in popular magazines, aspartame is responsible for totally divergent conditions ranging from hyperactivity to impotence.

On the other hand, scientific reports have repeatedly shown that aspartame is safe if used in sensible quantities.

In view of this controversy, let's have a look at aspartame and what highly reputable organisations have to say about this product.

What is aspartame?

Aspartame is an artificial sweetener produced from two amino acids and methyl alcohol. It is 160-220 times sweeter than sugar.

Using this sweetener will reduce kilojoule intake associated with the use of sugar in the daily diet and also permit individuals who need to reduce their sugar intake for medical reasons, such as diabetes, to still eat sweet-tasting foods.

Humans like sweet-tasting foods

It is thought that human beings are genetically programmed to like sweet foods and newborn babies are known to prefer a sweet taste to bitter or sour tastes.

Sugar as such is not harmful when eaten in moderation. Sugar only contains 4 cal or 16 kJ per gram and a teaspoonful will only provide 16 cal or 67 kJ to your energy intake.

Moderate intakes of sugar to make a diet more palatable are perfectly acceptable – even if you are slimming. Various diabetic associations around the world also permit diabetics to ingest small quantities of sugar.

However, humans in the modern world, where sweetened foods and beverages abound, may ingest so much sugar that it increases their energy intake and affects their health. On average in the USA, 16% of the energy is provided by sugar that is added to foods and beverages.

Sugar is also regarded as a cariogenic substance that contributes to tooth decay, if eaten between meals.

Consequently, researchers have developed a number of so-called artificial sweeteners, such as aspartame, which are much sweeter than sugar and have a much lower energy content.

A neat solution, but of course, there are always people who will regard such developments as potentially threatening and mount campaigns to discredit these discoveries. This has also happened to aspartame.

What do health authorities say?

If we disregard sensational scare stories and study what international, reputable organisations such as the American Dietetic Association (ADA), the Food and Drug Association (FDA) in the USA, and the European Commission's Scientific Committee on Food (SCF), have concluded, we may get more clarity about the safety or hazards of using aspartame.

a) American Dietetic Association (ADA)

The ADA recently published a comprehensive report in which they confirmed that artificial sweeteners (including aspartame) "are safe used in amounts specified by the FDA (see point b below)".

b) FDA

The FDA has classified aspartame as safe for human use at levels of 50mg/kg body weight per day. The estimated intake of aspartame in the USA is only 8,7mg/kg body weight per day, so individuals obviously ingest much less aspartame than is considered safe.

c) European Commission's Scientific Committee on Food (SCF)

The SCF already reviewed the safety of aspartame in 1988 and concluded that it is safe for use.

In 2001, the SCF reviewed more than 500 papers published in the scientific literature in the period 1988 to 2001, on aspartame's safety or lack thereof. The SCF concluded that, "there was no evidence to suggest a need to revise the outcome of their earlier risk assessment or the Acceptable Daily Intake (ADI) previously established for aspartame of 40mg/kg of body weight per day."

If we take these opinions of international expert committees into account, then it is evident that aspartame is regarded as safe for use by human beings and that nutritionists can recommend its moderate use in slimming and diabetic diets.

No evidence of the many supposed negative effects published in the popular media and on the internet was found.

Aspartame and phenylketonuria

Because one of the amino acids in aspartame is phenylalanine, people suffering from an inherited genetic defect called phenylketonuria (PKU), which makes them unable to metabolise phenylalanine, should not use aspartame or any food or beverage sweetened with aspartame.

PKU occurs in 1 out of every 10 000 individuals and is a serious, metabolic disorder which has to be treated by total avoidance of foods containing phenylalanine. Because phenylalanine occurs in most protein foods, the diet for PKU patients is restrictive and relatively difficult to apply.

All foods that contain aspartame are required by law to be labelled with a warning 'Contains phenylalanine' and/or 'Not for use by phenylketonurics', to alert PKU-sufferers that the product contains this amino acid.

The rest of us who do not suffer from PKU and in any case ingest phenylalanine every time we eat meat, fish, eggs, cheese or other protein-rich foods, are not affected by this aspect of aspartame.


For those readers who wish to avoid aspartame for other reasons and need to restrict sugar intake, alternative strategies may help.

Educate your taste buds not to want sweetened foods, by gradually reducing how much sugar you use over food and in tea and coffee. Drink soda water instead of other cold drinks, or just eat and drink smaller portions of sweetened foods and beverages.

Regarding the aspartame controversy, it should, therefore, be kept in mind that a great deal of research has been done on the safety of aspartame, and a number of highly respected international agencies have reviewed the results of this research and concluded that aspartame is safe for human use. – (Dr Ingrid van Heerden, DietDoc, May 2006)

(Harvard Health (2006) Artificial sweeteners: Okay in moderation. http:// - Article873179. Food Standards Agency (2005). Aspartame. ).


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Dr. May currently works as a fulltime endocrinologist and has been in private practice since 2004. He has a variety of interests, predominantly obesity and diabetes, but also sees patients with osteoporosis, thyroid disorders, men's health disorders, pituitary and adrenal disorders, polycystic ovaries, and disorders of growth. He is a leading member of several obesity and diabetes societies and runs a trial centre for new drugs.

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