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Artificial and natural sweeteners

Depending on who you talk to, artificial sweeteners are a useful alternative to sugar or a chemical minefield. So what are the facts about these sweeteners and what is their impact on our health? Jeni Pearce investigates.

Here’s what we cover:

Food is sweetened using a wide variety of ingredients, including sucrose (cane sugar), fructose (fruit sugar), lactose (milk sugar), glucose, honey, brown sugar, icing sugar, raw sugar and sweet syrups (maple, golden). These sweeteners all have an energy value (17kJ per gram).

‘Artificial sweeteners’ should really be called ‘alternative sweeteners’ as many of the latest types are not artificial but made from sugars that have been altered. Artificial sweeteners provide a sweet taste with few or no kilojoules so are often added to food and beverages. Often these sweeteners have a very intense sweetness, which results in very small amounts being used in food.

Common sweeteners

Three common sweeteners you’ve probably heard of are aspartame, saccharin and sucralose. Other lesser known sweeteners, used in table sweeteners and in foods and drinks on our supermarket shelves, are acesulphame potassium (Ace K), cyclamate, neotame, monk fruit and mannitol.

  • Saccharin was the first sweetener discovered in the late 1800s. It is 300 times sweeter than sugar and is the oldest and possibly most well-known of the alternative sweeteners. It has a slightly bitter taste and contains no energy (no kilojoules). Used as a table top sweetener, in drinks and in foods.
  • Aspartame is one of the most widely used and popular alternative sweeteners in food and beverages and has 200 times the sweetness of sugar. Made from two amino acids (the building blocks of proteins) it breaks down at high temperature so it can’t be used in baking or cooking. It is commonly used in cold beverages and is one of the most studied sweeteners. It does have an energy value (64kJ per gram) but as so little is used to sweeten food, the energy contribution is virtually zero. Used as a table top sweetener, in drinks and in foods.
  • Sucralose is actually derived from sugar but is 600 times sweeter and contains no energy. Sucralose is stable when heated making it ideal for cooking and baking. It can be found in an increasing range of foods like chewing gum, dressings, drinks, desserts, canned fruit and baked items. Used as a table top sweetener and in foods.
  • Acesulphame potassium (Ace-K) is usually found blended with other sweeteners to improve the taste and stability in foods. It is heat stable and contains no energy value. Used as a table top sweetener, in drinks and in foods.
  • Cyclamate is 30 times sweeter than sugar but when used with other sweeteners, usually saccharin, the sweetness of each is enhanced. Cyclamate is stable when heated. Used in table top sweeteners and in foods.
  • Mannitol is a sugar alcohol (see below) produced from natural sugars and helps to mask bitter tastes. It has half the sweetness of sugar and half the energy content so in a tabletop sweetener it is primarily used for its other properties. Also used in foods.
  • Neotame is one of the most intense sweeteners at 8000 times the sweetness of sugar so only very small amounts are added to sweeten processed foods.
  • Monk fruit has been used for centuries in Eastern medicine as a cold and digestive aid, and has been deemed safe for use as a sweetener by food authorities in the US, New Zealand, Australia, China, Japan and Canada. The juice is 100 to 200 times sweeter than sugar, so you only need a tiny amount to enjoy the same sweetness.

Sugar alcohols

Sugar alcohols include mannitol, sorbitol, isomalt and xylitol. They are used as sweeteners in products like chewing gums, sweets, chocolate bars and mints. Unlike sugar, the sugar alcohols have either a low or no ‘cariogenic effect’, that is they don’t cause dental caries. (Dental caries is an infectious disease which damages the structures of teeth. Tooth decay or cavities are consequences of caries.) Sugar alcohols are found naturally in many fruits and vegetables but are commercially produced from carbohydrates like glucose, sucrose and starch.

During the recent low-carb diet trend, sugar alcohols were added to many foods to lower their total carbohydrate content yet still provide a sweet taste. Sugar alcohols do contain energy (between 32-64kJ compared to sugar at 70kJ per teaspoon) but they are absorbed more slowly and have little or no effect on blood glucose levels. They have little advantage for weight loss, so check the kilojoule content of any ‘no sugar added’ products.

What about Stevia?

Stevia is a sweetener extracted from the leaves of the Stevia rebaudiana Bertoni plant. Stevia has been used for centuries in Argentina, Brazil and Paraguay to sweeten foods and drinks and is widely cultivated in Asia. While fresh leaves are reported to be 15-20 times sweeter than sugar, extracts from the leaves can be up to 300 times sweeter.

In New Zealand stevia may be sold as a dietary supplement but is not approved for use as a food additive. The key issue is the relatively limited research data about stevia.

The Food and Agriculture Organisation/World Health Organisation (FAO/WHO) Joint Expert Committee on Food Additives (JECFA) met in 2004 to review the scientific evidence about the safety of stevia. One of the problems they highlighted was there are not common specifications for the stevia that is traded. In other words, the amount of active constituents in stevia can vary. They also said more information was needed about the metabolism and pharmacological effects of stevioside (a major constituent of stevia) in people.

An application to Food Standards Australia New Zealand (FSANZ) is under consideration to permit the use of Steviol Glycoside (leaf extract) as a food additive in New Zealand.

Beware the internet

Many people have concerns about the safety of artificial sweeteners, typically after reading disturbing information online. Unfortunately, while the internet can be a valuable research tool for any topic under the sun, it is also difficult to separate fact from fiction.

Many myths about sweeteners persist from misunderstanding and rumour. Scientific data is regularly misquoted or the wrong interpretation made. It is common to find reports of out-dated research when there is a large body of more recent information to contradict the early data.

Another warning sign is a reliance on testimonials. These are the fall-back for those who can’t even find enough obscure studies to back them up. It’s like saying: ‘My next-door neighbour ate cabbage every day and she died of cancer, therefore cabbage causes cancer’. Cause and effect gets all mixed up.

When surfing the net, look out for emotive WORDS IN CAPITALS and frequent use of exclamation marks!!!! These are a useful clue that you may have stumbled into someone’s over-active imagination or the work of a conspiracy theorist.

Reports designed to alarm often deliberately use scientific words when common ones would do. For example, polysaccharides sounds much scarier than starch; and ascorbic acid is just the technical term for vitamin C.

When researching a health or nutrition topic it is advisable to start with reputable websites (such as government agencies) and use their links to other websites.

But beware the spin doctor. Some political parties use emotive issues like artificial sweeteners to get attention and make deliberately alarming statements in press releases. This is a good way to get a newspaper headline, but not so great at informing us about an issue, as too often the scientific evidence is incorrectly interpreted or just ignored altogether. And all we remember is the scary headline.

The health impacts


If you Google ‘aspartame’ and start reading, you could be forgiven for becoming very nervous about your health: it seems that ingesting aspartame will cause an extraordinarily wide range of complaints, pretty much from A to Z. Why is this additive allowed in our food supply, you ask yourself?

Aspartame is broken down into aspartic acid, phenylalanine and methanol in our bodies. One popular piece of misinformation about aspartame is that it causes methanol toxicity which mimics multiple sclerosis, but there is simply no evidence for this, nor any logical explanation of why it should be so. The methanol and other compounds mentioned are not in any way sinister, they are found naturally in other foods and our bodies are able to absorb, metabolise and excrete them.

When surfing the net, look out for emotive WORDS IN CAPITALS and frequent use of exclamation marks!!!! These are a useful clue that you may have stumbled into someone’s over-active imagination or the work of a conspiracy theorist.

A large Italian study raised concerns suggesting a link between aspartame and an increased risk of cancer in rats. This report received wide media coverage. The European Food Safety Authority (EFSA) assessed this aspartame study along with currently available evidence and concluded that there is no need to further review the safety of aspartame nor revise the acceptable daily intake (ADI) for aspartame. The National Cancer Institute in the US recently conducted a beverage consumption study with nearly half a million people and the results indicated that there is no relationship between aspartame use and cancer in humans.

There is a requirement to label any food containing aspartame or aspartame-acesulphame to the effect that the product contains phenylalanine. (See What is phenylketonuria? below.)


In the 1970s concerns were raised following studies using rats fed high doses of saccharin, which linked it to bladder cancer. Since then it has been established that the mechanism causing the tumours in rats is not relevant to humans. Saccharin is not metabolised in humans but passes out of the body unchanged.

Despite extensive research over the last 20-30 years, there is no conclusive evidence of a link between saccharin and bladder cancer (or any other cancer) in humans.


Sucralose caused shrunken thymus glands and enlarged liver and kidneys when fed to rats in extraordinarily large doses. (It’s worth remembering that many food constituents would be harmful at such exceptionally high doses.)

Before the FDA in the US approved sucralose for use their scientists reviewed over 110 studies in humans and animals, many of which were designed to find any toxic effects including carcinogenic, reproductive and neurological effects. They were satisfied it is safe.

What is phenylketonuria?

You may have seen the warning on the label of foods and beverages containing aspartame: ‘Contains phenylalanine’. Phenylketonuria (PKU) is a rare genetic disorder that prevents the body breaking down the essential amino acid phenylalanine, which is one of the amino acids found in aspartame. In people with PKU the phenylalanine builds up in the tissues of the body and can cause irreversible brain damage. We are all tested for this disorder at birth. People with PKU must follow a special limited diet which strictly limits their intake of phenylalanine, especially in the early and teenage years.

NZ food safety

Food Standards Australia New Zealand (FSANZ) undertakes safety assessments before any food additive can be used. It checks the safety of the additive at the levels requested to be permitted in a food and that there are good reasons for the use of the additive. As part of the safety assessment, the likely level of consumption of the additive for different groups of people if the additive were permitted is looked at. This is then compared to the acceptable daily intake. If it is well within safe limits, FSANZ then defines the maximum level of the additive that can be used in particular foods. Aspartame and sucralose are the only sweeteners recommended during pregnancy.

For more information on the Food Standards Code and the food additives permitted in New Zealand, go to Food Standards Australia NZ.

Acceptable daily intake

The acceptable daily intake (ADI)* is an estimate of the amount that could be consumed every day over a lifetime without adverse effects. It’s worth noting that the ADI is set at a very conservative level. And usual intake is well below the acceptable daily intake.

Saccharin5mg8.5 serves sweetener
Aspartame40mg12 cans diet soda
Acesulfame K15mg25 cans diet soda
Sucralose15mg15 cans diet soda

*These volumes are related to the safety of the sweetener and do not imply that such large daily volumes of carbonated drinks are appropriate in a balanced diet. 

Benefits of artificial sweeteners

Artificial sweeteners are useful to help people satisfy a desire for sweet foods or the sweet taste without the extra kilojoules. There is no evidence to suggest using artificial sweeteners creates a sweet tooth or promotes a greater intake of sweet foods.

Eating chewing gums and sweets with low- or no-kilojoule artificial sweeteners between meals is also kinder to teeth.

Diet cordials and fizzy drinks have a much lower energy value than the sweetened original, making them useful for those wishing to limit sugar in their diet. Of course, it is worth remembering that water is the most economical non-sweetened beverage available.

You can have too much

High intakes of sugar alcohols are known to have a laxative effect and in some cases can cause diarrhoea. Excessive intake of sweets, mints or gum with other alternative sweeteners can cause gastrointestinal discomfort such as bloating, increased wind or diarrhoea.

While acknowledging they play a useful role, Diabetes New Zealand advises against using large amounts of alternative sweeteners. Regular users are advised to vary the sweetener used to avoid excessive intake of any one.

Inappropriate use

If you are using moderate amounts of artificial sweeteners then you can be assured they are safe, but it is unwise to consume excessive amounts or misuse products containing these sweeteners.

Eating disorders

People who suffer from disordered eating sometimes consume large amounts of diet products to lower their energy intake or provide bulk in the diet without energy. Typical foods include diet cordials and sodas, low sugar or no sugar chewing gums, diet jams, diet jelly and diet desserts. I have known young girls with eating disorders to drink up to 12 cans of diet soda a day to buffer the effects of hunger. Fortunately this sort of behavior is rare.

High intake in children

Young people who have large intakes of diet cordials, diet soda and diet jelly could be at risk of consuming very high levels of artificial sweeteners. These foods should only be used as treats and for special occasions rather than on a regular basis. Because of their smaller size, children should not consume the same amount of these sweeteners as adults.

The diet trap

Some people mistakenly believe the use of artificial sweeteners promotes weight loss. These sweeteners can be effective when replacing the energy content of sugar and sweet foods but they can’t melt away the kilos.

Using an artificial  sweetener will not guarantee weight loss or prevent weight gain by itself. Remember ‘sugar-free’ does not translate into ‘eat a larger serving’, ‘have an extra scoop’ or ‘eat as much as you like’. Drinking diet cordials and sodas while eating a candy or chocolate bar is not going to cancel the other kilojoules out. Using an artificial sweetener may be part of your weight control strategy but physical activity, energy balance, portion control and good food choices are all needed as well.

Know your table-top sweeteners


  • Powder: contains aspartame and acesulphame potassium. One teaspoon has 8.1 kJ. It is suitable for some baking and cooking.
  • Tablets: also contain aspartame and acesulphame potassium. One tablet has 1.2 kJ.


  • Granules: contain cyclamate, saccharin and mannitol. One teaspoon has <13 kJ. Granules are suitable for some baking and cooking.
  • Liquid: contains cyclamate and saccharin. One serve = eight drops. It is suitable for baking and cooking.


  • Granules: contain sucralose. One teaspoon has 8 kJ. It is suitable for baking and cooking.
  • Tablets: also contain sucralose. One tablet has 1.3 kJ.


  • Liquid: contains cyclamate and saccharin. 4-5 drops have 0 kJ. The liquid is suitable for baking and cooking.
  • Tablets: contain saccharine. One tablet has 0 kJ.

Weight Watchers

  • Powder: contains aspartame. One teaspoon has 13 kJ. It is NOT suitable for baking or cooking.
  • Tablets: contain saccharin. One tablet has <1 kJ.

These are examples only: there are other brands available and some brands listed have more product forms. All servings give the equivalent sweetness to 1 teaspoon of sugar; 1 teaspoon of sugar contains 70kJ. The reason for varying energy content (kilojoules) is the difference in ingredients used to make up the powder, tablet or liquid.

Know the numbers

These are all sweeteners approved for use in New Zealand foods. Some are used in food manufacturing because they are intense sweeteners; others are less intense but used for other processing or end-product attributes. A blend of sweeteners is often used to provide sweetness and stability to suit particular foods or beverages.

420Sorbitol or sorbitol syrup
950Acesulphame potassium (Ace K)
952Cyclamate or calcium cyclamate or sodium cyclamate
962 Aspartame-acesulphame salt
965Maltitol and maltitol syrup or hydrogenated glucose syrup

The NZFSA produces a booklet listing additives under each class (preservatives, sweeteners, etc). This can be downloaded from their website www.nzfsa.govt.nz (search for ‘food additives’). A full list of all approved food additives is also available at Food Standards Australia New Zealand in both alphabetical and numerical lists.

Cooking with sweeteners

All can be used to add to foods and drinks, like tea or coffee. However, if you want to use them in cooking instead of sugar, there are some things to be aware of, as sweeteners do not always work in recipes in the same way as sugar.

Here are some guidelines:

  • Some sweeteners (mostly aspartame-based products) are not suitable for use in dishes that are baked at high temperatures or for a long time, as they lose sweetness when heated for long periods. Some can only be used in uncooked or lightly-cooked items (like cheesecakes, pie fillings etc) or added after baking. Check the packaging for details if you are not sure. Liquid sweeteners, in general, are suitable for baking and don’t lose sweetness.
  • If using granulated sweeteners that work ‘spoon for spoon’ with sugar, you can replace by volume. But make sure you don’t replace ‘weight for weight’, as sweeteners are much lighter and more concentrated than sugar.
  • Sweeteners don’t brown or caramelise in the same way as sugar. Try using milk as a glaze instead if your dish does not brown.
  • If you replace sugar with sweetener in baking, you may find the final texture is different from the sugar version. Biscuits tend to be softer, and cakes tend to be harder. You may also find they won’t keep as long. This is because sugar acts as a preservative in baked goods.
  • Baking times may be different when replacing sugar with sweetener (shorter or longer, depending on the recipe).
  • If using sweetener in a favourite recipe, experiment. You may find it useful to replace half the sugar only at first to retain the volume and texture of your cake or cookies.

Bottom line

Artificial sweeteners have their place when used sensibly. They are useful to help satisfy a desire for sweet foods without adding the kilojoules. Used in moderation, these sweeteners are safe and effective for reducing the energy value in food and beverages that would otherwise contain sugar.

Related content: Artificial sweeteners in fizzy drinks and HFG guide to sweeteners.

Date modified: 25 September 2021
First published: Jan 2007


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