Feedback from our readers tells us food additives are a major concern for consumers. We look at the latest research into questionable food additives permitted in Australia - and give our verdict on the ones you'd do best to avoid.

Individuals and consumer advocacy groups are often warning about certain food additives, saying they're unsafe and should be avoided. On the flipside, the food manufacturing industry and regulators say there are good reasons to use additives — to prevent food poisoning or extend a food's storage life, for example.

Additives and processed food go together — you rarely get one without the other. The more highly processed foods you eat, the more additives you'll eat too. So the easiest way to avoid them is to eat mainly fresh and only lightly processed foods (such as canned tomatoes and frozen vegetables). But you can't easily avoid eating additives altogether - even packaged bread often has several. And a small number of dietary additives usually isn't a problem for most people.

The safety evidence for food additives is reviewed by Food Standards Australia New Zealand (FSANZ) before they're approved for use, but some people still argue that certain approved food additives lead to health problems. 

Controversial additives

The additives in question are from the following key categories:

  • Colours (code numbers in the 100 range) that add or restore colour to foods.
  • Preservatives (200 range) that help protect against food deterioration caused by micro-organisms.
  • Antioxidants (300 range) that slow or prevent the oxidative deterioration of foods, such as when fats and oils go rancid.
  • Artificial sweeteners (including intense sweeteners in the 900 range, and bulk sweeteners such as sorbitol, 420) impart a sweet taste for fewer kilojoules than sugar.
  • Flavour enhancers (mainly in the 600 range) that improve the flavour and/or aroma of food.

Other key additives

  • Emulsifiers (mostly in the 400 range) help prevent oil and water mixtures (in mayonnaise, for example) from separating.
  • Stabilisers (mostly in the 400 range) maintain the uniform dispersal of substances in a foods like ice cream.
  • Thickeners (including vegetable gums, which have code numbers mostly in the 400 range, and modified starches, with code numbers in the 1000 range) increase the viscosity of foods like thickened cream to a desired consistency.

Colours

Colours and hyperactivity

The concern over artificial colours was fuelled by a UK government-funded study which concluded that a mixture of colourings and the preservative sodium benzoate (211) could be linked to increased hyperactivity in some children.

The colours studied were tartrazine (102), quinoline yellow (104), sunset yellow FCF (110), carmoisine (122), ponceau 4R (124) and allura red AC (129).

The Food Standards Agency, the British food regulator, is encouraging food manufacturers to find alternatives to these colours and reports that some manufacturers and retailers in the UK have already taken action to stop using them.

Within the EU, foods containing these colours are now labelled with a mandatory warning: "May have an adverse effect on activity and attention in children."

In Australia, the supermarket chain Aldi has removed these six colours from its own-brand products, as well as eight more colours: amaranth purple (123), erythrosine cherry red (127), indigo blue (132), brilliant blue (133), green (142, 143), black (151) and brown (155).

However, FSANZ say dietary exposure to added colours in food and beverages doesn't pose a public health and safety concern for children in Australia.

Colours and allergies

In the 1980s, the concern centred on tartrazine, an artificial colour that can cause mild allergic-type reactions. Sunset yellow FCF can have a similar effect. Some animal studies have indicated sunset yellow can cause tumours, but the results aren't consistent with other studies on rats and mice.

Natural additives aren't necessarily safer than artificial ones. The natural colouring annatto (160b), for example — typically found in margarine, Cheshire cheese, smoked fish and cakes — can cause allergic-type reactions in some people.

>Colours and cancer

Two long-term feeding studies demonstrated that erythrosine (127) increases the incidence of thyroid tumours in rats, but a review of these and other available data by JECFA, an international scientific expert committee administered jointly by the Food and Agriculture Organisation of the United Nations and the World Health Organisation (WHO), concluded the colour is safe. Even so, its use in Australia is restricted to glacé cherries.

Tests have linked allura red AC (129) with cancer in mice, but evidence of harm isn't consistent or substantial. Claims that brilliant blue FCF (133) is carcinogenic are largely unsubstantiated.

Our verdict

Often overused, colours aren't needed in food to do anything functional, but purely for looks. In other words - they're there for the marketing.

And given that they're most often found in foods like cordials, lollies, cakes and soft drinks, which we're recommended to have only as an occasional treat anyway, it's easy enough to avoid colour additives by only eating these foods rarely, if at all.

In light of the UK food regulator's decision to push for industry action to remove some of these colours altogether, we'd like to see FSANZ review the situation in Australia.

In the meantime, if your child shows signs of hyperactivity, cutting out foods that contain these colours from their diet could help. However, if you think you or your child has an intolerance or allergy to any food or food additive, seek advice from your medical practitioner or dietitian - just cutting out certain foods may not be the answer.

Preservatives

Soft drinks

In drinks, the combination of sodium benzoate or potassium benzoate (212) and ascorbic acid (vitamin C, both naturally occurring and the additive 300) can result in the formation of benzene, a known carcinogen. Exposing the bottle to heat or light during transport or storage can boost the amount of benzene formed.

FSANZ tested 68 flavoured drinks, including flavoured mineral waters, cordial, fruit juice and fruit drinks, and found 38 of the samples contained trace levels of benzene. While the majority had benzene levels below WHO guidelines for drinking water - 10 parts per billion (ppb) - some contained levels up to 40 ppb - 1 ppb is the reference level for benzene in Australia's more stringent drinking water guidelines.

On top of that, a national diet survey in 2005 found that young children who consume lots of drinks that contain a form of benzoate (non-cola soft drinks, orange juice and cordial, for example) could be exceeding the acceptable daily intake (ADI) for benzoates.

Processed meats

The food preservatives sodium nitrite (250) and sodium nitrate (251) - typically found in processed cured meats like ham and bacon - are both listed as "probably carcinogenic to humans" by WHO's International Agency for Research on Cancer, because they can be converted into nitrosamines in the stomach and nitrosamines increase the risk of cancer.

Bread

Calcium propionate (282) prevents mould growth on bread and is often heavily used in humid, tropical areas. It's been linked to migraines and behavioural and learning problems, but these reports lack scientific credibility.

Wine and dried fruit

Preservatives that contain sulphur (220-228), including sulphur dioxide (220), which is used in wine and dried fruit, can trigger asthma attacks. The 2005 national diet survey found that young children who eat lots of foods that contain sulphites, such as dried apricots, sausages and cordial, could be exceeding the ADI for sulphites.

Our verdict

Exposure to benzene in food and drink products may be small when compared with breathing air that contains benzene from traffic pollution or tobacco smoke, but it's unnecessary. So it makes sense to avoid drinks that contain benzoates and ascorbic acid.

The Cancer Council now recommends limiting or avoiding processed meats such as sausages, frankfurts, salami, bacon and ham. But also keep in mind that the cancer risk is relatively small and that sodium nitrite prevents the growth of bacteria that cause botulism poisoning – which can be more immediately deadly.

Sulphur dioxide should be avoided by people who have asthma.

Antioxidants

BHA

BHA – butylated hydroxyanisole (320) – is typically found in margarine and spreads, salad dressings, walnuts and pecans, and instant mashed potato.

It's listed as "possibly carcinogenic to humans" by WHO's International Agency for Research on Cancer, and some studies have demonstrated that it causes cancer in rats, mice and hamsters.

But these cancers are controversial because they occur in the forestomach, an organ that humans don't have.

Our verdict

While it's considered safe at the low level of use permitted, BHA can be replaced in foods by safer chemicals (such as vitamin E), safer processes, or simply left out. Check labels if you want to avoid it.

Artificial sweeteners

Artificial sweeteners can be hundreds of times sweeter than sugar. These intense sweeteners are typically used in diet and low-sugar foods and drinks. Reports link many of them to cancer.

Artificial sweeteners and cancer

In the 1970s, several studies of rats that were fed very large amounts of saccharin (954) found its use was associated with a higher incidence of bladder cancer. It was banned in Canada, and until 1996 products containing saccharin in the US had to be labelled with a warning. But research in humans largely failed to turn up that risk, and in 2000 the US Government's National Toxicology Program delisted saccharin as a possible carcinogen.

Research in 2005 from the European Ramazzini Foundation (updated in 2007) found feeding rats aspartame (951) at simulated doses around levels considered safe for humans increased the rats' risk of leukaemia, lymphoma and breast cancer.

Another intense sweetener, cyclamate (952), was banned in Canada, the UK and the US over 30 years ago because animal studies indicated links to cancer, but this ban was lifted in the UK in 1996 following further studies. However, another UK survey found some children could be consuming up to twice the ADI for cyclamate. A survey by FSANZ similarly found that 5% of Australian kids were exceeding the acceptable daily intake (ADI0 for cyclamate. Cyclamate is still approved for use in Australia.

Artificial sweeteners and pregnancy

In 2010 Danish researchers linked the consumption of artificially sweetened, but not sugar-sweetened, soft drinks to preterm delivery of babies. Though the study couldn't distinguish between the various artificial sweeteners, aspartame and acesulfame-potassium are the most widely-used. The authors suggested that the cause of the problem might be the methanol released when aspartame breaks down in the container or in the body. More research is needed on this issue. In the meantime, pregnant women might want to make a special effort to avoid consuming artificial sweeteners.

Artificial sweeteners and other health concerns

Aspartame has also been linked to headaches, allergies and changes in behaviour. But a review funded by industry of more than 500 studies, including the Ramazzini research, concluded that aspartame is safe at current levels of consumption as a non-nutritive sweetener. While many scientists remain concerned about the Ramazzini Foundation results, FSANZ and the US food regulatory authority told us they see no reason to alter their position that aspartame is safe.

Our verdict

There's certainly a bigger risk to your health from being overweight than there is from eating artificially-sweetened products.

Sweeteners have often been recommended to aid in weight loss, but there's conflicting research about the health benefits of artificially-sweetened drinks. Some studies show that regular consumption of artificially-sweetened beverages reduces the intake of calories and promotes weight loss or weight maintenance, other research shows no effect, and some studies even show weight gain.

The jury's still out on the absolute safety of artificial sweeteners, so it makes sense to limit your and your children's intake of artificially-sweetened foods and drinks. Losing weight without the help of artificial sweeteners would be the win/win situation.

Those who should definitely avoid aspartame are people with the rare disorder phenylketonuria, or PKU, who must limit their intake of phenylalanine, an amino acid in aspartame.

Flavour enhancers

Flavour enhancers such as glutamates (621-625) are found in many foods, including packet soups, flavoured noodles, sauces and savoury snacks. When glutamate touches the taste receptors on our tongue, it gives food a savoury taste (known as umami). Mixed with a meal, glutamate balances, blends and enhances the total perception of flavour.

Some foods – tomato products, fermented sauces (such as soy sauce or oyster sauce) and long-matured cheeses such as stilton and parmesan – are naturally high in glutamate.

Because MSG has such a bad name, many manufacturers use other sources of glutamate to give processed foods the extra taste. These include protein extracts from corn, yeast or soy, which are processed to release the glutamate.

People sensitive to monosodium glutamate (MSG, 621) may have short-term reactions such as headaches, flushing and numbness when they eat foods that contain large amounts of MSG, and some asthmatics may also be susceptible.

Our verdict

For most people MSG and other glutamates are harmless. If you're sensitive to MSG, check labels for it.

Unlabelled additives

You can avoid specific additives in packaged foods by looking at the ingredients list.

Additives must be identified by their function, then by their name (for example, preservative: sulphur dioxide), or by their code number (for example, preservative 220).

But the fact that either the name or code number is listed means it can be hard to compare which additives are in different products. And there are some exceptions:

Flavourings

Whether natural, nature-identical or artificial, flavourings don't have code numbers and may be labelled simply as 'flavouring' or 'flavour'. According to FSANZ, the vast number of flavouring substances permitted in food means it wouldn't be realistic to require the names to be listed individually.

The 5% loophole

If an additive is present in an ingredient and that ingredient makes up less than 5% of the complete food product - and the additive isn't considered to perform a technological function in the final food - it doesn't have to be listed.

Processing aids

These aren't required to be listed, even though traces may be present in the food. Enzymes are an example - they have multiple uses in food production, including pumping up bread loaf volume, assisting with the removal of meat protein from bones and breaking down fruit to release more juice.

Ice structuring protein (ISP), a genetically modified fish protein used in ice cream to control the size and growth of ice crystals, is another.

Our verdict

We want one clear labelling system for additives so it's easier to avoid them and to compare what's in different foods.

Food labelling should also be extended to include all additives, including processing aids, even if they're present in very small amounts.

How additives are regulated

The use of food additives in Australia is governed by the Food Standards Code and regulated by FSANZ. When applying to use a new additive, a manufacturer must provide evidence to FSANZ of its safety, as well as the technological reason for its use. FSANZ reviews the safety evidence before an additive is approved for use and reviews new research as it becomes available, but doesn't undertake safety testing of its own.

On top of that, an exposure assessment estimates the likely amount that would be consumed if the food additive were permitted for use. This amount is compared to the acceptable daily intake (ADI) recommended by scientific experts, which is the amount you can consume every day without damaging your health. FSANZ then recommends a maximum level of the food additive permitted in particular foods, based on technological need and providing it's within safe limits.