Are high intensity sweeteners safe?

Prof. Walker: All sweeteners have undergone extensive research and development and rigorous safety assessments and evaluation before they are approved. Once approved by regulatory bodies, they are deemed safe for human consumption.

Acesulfame-K, aspartame, sucralose, saccharin, cyclamate and alitame have all been reviewed and found safe by the Joint Expert Committee on Food Additives (JECFA) of the United Nations Food and Agricultural Organization and the World Health Organization.

Is there a limit to the amount of sweeteners we can safely eat?

Prof. Walker: International regulatory bodies use the concept of an Acceptable Daily Intake (ADI) to determine how much of a food additive can be safely eaten. The ADI represents an intake level that if maintained each day over a person's lifetime would be considered safe. ADIs are more than 100 times less than the smallest amount that might cause an adverse reaction in experimental studies and are applicable to all age groups unless otherwise stated.

While all approved sweeteners are deemed as safe, the ADI for low-calorie sweeteners varies between products.

* Based on intake by a person with a body weight of 60 kilograms.

There has been a lot of "noise" on the Internet claiming links between aspartame and adverse health effects including an increase in the incidence of brain tumours and seizures. Has JECFA looked at these claims?

Prof. Walker: These claims are false. Aspartame has been kept under review by the US Food and Drug Administration (FDA), the FAO/WHO Joint Expert Committee on Food Additives (JECFA), and the Scientific Committee on Food of the European Union (SCF) who have all concluded that it is safe. It has been approved by government regulatory authorities in over one hundred countries. Extensive experimental, clinical and epidemiological research conducted on aspartame shows there is no link between aspartame and any adverse health effects.

What does the phenylketonuria warning label on products containing aspartame mean?

Prof. Walker: Phenylketonuria (PKU) is a rare hereditary disease where affected individuals lack the enzyme to properly metabolise phenylalanine, an amino acid. People suffering from phenylketonuria need to restrict their intake of phenylalanine from all sources including common protein foods such as meat and milk, and products containing aspartame. The labelling informs PKU sufferers of the presence of phenylalanine in the product. The wording of the label varies by country. In countries such as Canada, the European Union and Japan, the label is written as "aspartame, contains a source of phenylalanine", and in the United States the label is written as "Phenylketonurics: contains phenylalanine."

Why was cyclamate banned in the United States?

Prof. Walker: Cyclamate was banned in the United States after a study showed that some rats developed bladder cancer when fed extremely high amounts of a cyclamate and sodium saccharin mixture. Several further studies in rats and mice have since confirmed that cyclamate is not carcinogenic and more than 30 subsequent studies of human populations have found no excess cancer risk in subjects that have consumed cyclamate for a number of years. The Joint FAO/WHO Expert Committee on Food Additives and the US Food and Drug Administration have concluded that cyclamate is not carcinogenic.

Why must foods containing saccharin carry a warning label in the United States?

Prof. Walker: The FDA proposed a ban on saccharin in 1977 following a study showing that in large doses - equivalent to the human consumption of 750 cans of diet soda every day over a lifetime - some male rats developed bladder cancer.

A congressional moratorium was placed on the ban to allow for more research to be conducted into saccharin's safety. Although the FDA officially withdrew the proposed ban in 1991, United States law still requires a warning label on all saccharin-containing products. Recent research shows that the mechanism that can cause saccharin-fed male rats to develop cancer is unique to the male rat and is not relevant to humans.

Saccharin has been thoroughly reviewed and approved for use by the FAO/WHO Joint Expert Committee on Food Additives (JECFA). In the United States, many scientists believe there is no longer a need for the warning label.

Can eating high intensity sweeteners help people lose weight?

Prof. Walker: High intensity sweeteners taste similar to sugar but are much sweeter and contain virtually no calories. They can play a useful role in helping persons to maintain a healthy weight by providing good tasting alternatives to food products that are typically higher in calories. High intensity sweeteners are clearly an option for reducing the total calorie intake in our diet as they can fit into a nutritionally balanced weight loss/weight control regime, however, they will not magically solve weight problems. Successful weight management requires habits that include a balanced diet and regular physical activity.

Can people with diabetes consume high intensity sweeteners?

Prof. Walker: Yes, high intensity sweeteners are safe to use by people who have diabetes.

Diabetes is a condition that results from the body's inability to make or use insulin. Insulin moves sugar in the blood into cells where it is converted into energy. While the consumption of sugar does not cause diabetes, an important part of diabetes management is to maintain blood sugar levels within healthy limits. High intensity sweeteners can help by providing a sweet taste without increasing blood sugar levels.

Can high intensity sweeteners cause dental caries (tooth decay)?

Prof. Walker: No. High intensity sweeteners cannot be fermented by bacteria in the mouth and do not produce acids that erode tooth enamel. They cannot, therefore, cause dental decay.

How does a new high intensity sweetener get approved for use in foods and beverages? The most common way is for manufacturers to petition the local regulatory body by providing extensive information and data on the product. In the course of what is usually a lengthy and intensive review, the regulatory body requires substantial supporting data for their scientists to analyse. At a minimum, the following information must usually be provided:

• How will the product be consumed?
• How much of the product will be consumed by various groups within the population?
• Who, including children and pregnant/lactating women, will consume the product?
• What does the product do as an additive in food?
• Is the product toxic and what levels are safe?
• Does the product have the potential to cause any adverse health effects? Does it affect reproduction? Is it stored in the body? Is it broken down into other ingredients and if so, what is their safety profile? Does the product have the potential to cause an allergic reaction?
• How and where is the product made, who makes it and how pure is it?
• Is the ingredient suitable for food processing and cooking?

During the approval process, an acceptable daily intake for the product is often determined.

The process does not stop with the approval. The product is generally monitored for consumer complaints. In addition, dietary surveys are used to track consumption and usage in many countries.