Walk down any supermarket aisle and you will find hundreds of products containing ingredients most people cannot pronounce. These are food additives - substances added to food for specific purposes like extending shelf life, improving texture, adding colour, or enhancing flavour.
Not all additives are harmful. Many are completely safe and serve useful purposes. But some have been linked to health concerns in published research, and knowing which ones to look for on a label can make a real difference to the quality of food you bring home.
This guide covers the additives that appear most frequently in packaged food across the UK, Australia, and New Zealand - what they do, what the research says, and how to identify them on labels.
What are food additives?
Food additives are substances that are intentionally added to food during processing or preparation. They serve a range of technological functions and are assigned code numbers - known as E-numbers in the UK and Europe, or INS numbers internationally - so they can be identified across different languages and regions.
All approved additives have been assessed for safety by relevant food authorities including the European Food Safety Authority (EFSA), Food Standards Australia New Zealand (FSANZ), and the UK Food Standards Agency (FSA). However, safety assessments are based on typical dietary exposure, and research continues to evolve over time.
How to read additive codes on labels: In the UK and Australia/NZ, additives are listed either by their full name (e.g. "sodium nitrite") or by their E-number/code number (e.g. "E250" or "preservative 250"). Both mean exactly the same thing.
Additives flagged by major health authorities
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Preservatives
Sodium Nitrite & Sodium Nitrate - E250, E251
Used in processed meats including bacon, ham, salami, hot dogs, and cured sausages to prevent bacterial growth and maintain colour. The International Agency for Research on Cancer (IARC) has classified consumption of processed meats - largely due to nitrite/nitrate content - as a Group 1 carcinogen (sufficient evidence of cancer in humans), particularly linked to colorectal cancer.
Where you find it: Bacon, ham, salami, corned beef, hot dogs, smoked meats, canned meats.
Source: IARC / EFSASodium Benzoate - E211
A common preservative used in soft drinks, fruit juices, and condiments. When combined with vitamin C (ascorbic acid) in a product, sodium benzoate can form benzene - a known carcinogen - particularly in acidic, high-temperature conditions. Studies have also linked sodium benzoate to increased hyperactivity in children when combined with certain artificial colours.
Where you find it: Fizzy drinks, fruit drinks, salad dressings, pickles, jams.
Source: EWG / EFSABHA & BHT - E320, E321
Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are antioxidant preservatives used to prevent fats and oils from going rancid. IARC classifies BHA as a possible human carcinogen (Group 2B). BHT has shown similar concerns in some animal studies. Both are restricted or banned in some countries including Japan and certain EU applications.
Where you find it: Crackers, cereals, crisps, instant noodles, chewing gum, preserved meats.
Source: IARC / EWGArtificial colours
Artificial Food Dyes - Red 40 (E129), Yellow 5 (E102), Yellow 6 (E110)
These synthetic dyes are used to make food more visually appealing. A landmark 2007 study published in The Lancet, commissioned by the UK Food Standards Agency, found that a mixture of these dyes caused increased hyperactivity in children. As a result, the EU now requires products containing these dyes to carry the warning: "may have an adverse effect on activity and attention in children." In Australia and NZ, the same dyes are permitted but the warning label is not required.
Where you find it: Sweets, fizzy drinks, fruit-flavoured snacks, breakfast cereals, cake mixes.
Source: EFSA / UK FSATitanium Dioxide - E171
A white colouring agent that has been used in confectionery, chewing gum, and certain sauces to create a bright white appearance. EFSA concluded in 2021 that titanium dioxide can no longer be considered safe as a food additive, and it was subsequently banned in food products across the EU. It remains permitted in Australia, NZ, and the UK, though its use is under review.
Where you find it: White confectionery, chewing gum, some sauces and dressings, icing.
Source: EFSAFlavour enhancers
Monosodium Glutamate (MSG) - E621
MSG is added to food to enhance savoury flavour. It occurs naturally in foods like parmesan cheese, tomatoes, and soy sauce. Some people report headaches, flushing, or other symptoms after consuming MSG - sometimes called "MSG symptom complex" - though well-controlled scientific studies have not consistently confirmed a causal link in the general population. EFSA considers MSG safe at typical dietary levels.
Where you find it: Instant noodles, crisps, soups, fast food seasonings, flavoured snacks.
Source: EFSASweeteners
Aspartame - E951
One of the most widely used artificial sweeteners, found in thousands of "diet" and "sugar-free" products. In July 2023, IARC classified aspartame as "possibly carcinogenic to humans" (Group 2B) based on limited evidence. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) maintained that the acceptable daily intake remains safe for most consumers, but recommended further research. The World Health Organisation has also advised against using non-sugar sweeteners for weight management.
Where you find it: Diet drinks, sugar-free chewing gum, tabletop sweeteners, low-calorie yoghurts, flavoured water.
Source: IARC / WHO / EFSAAdded sugar - harder to spot than you think
Added sugar is not technically an additive in the E-number sense, but it is one of the most significant ingredients to watch on a label - and food manufacturers use over 60 different names for it.
Common names for added sugar include: glucose, fructose, dextrose, maltose, sucrose, corn syrup, high fructose corn syrup, rice syrup, agave, agave nectar, evaporated cane juice, invert sugar, golden syrup, malt extract, maltodextrin, and fruit juice concentrate.
Tip: Ingredients are listed in order of quantity, from most to least. If sugar (under any name) appears in the first three ingredients, the product is high in added sugar.
Emulsifiers and thickeners to be aware of
Carrageenan - E407
A thickener and emulsifier derived from red seaweed, used widely in dairy products, plant milks, and processed meats. Some animal and laboratory studies have suggested carrageenan may promote gut inflammation, though human evidence remains limited. EFSA has maintained its safety approval while noting uncertainties at high intake levels.
Where you find it: Oat milk, almond milk, chocolate milk, cream, deli meats, infant formula.
Source: EWG / EFSACarboxymethylcellulose (CMC) - E466
A widely used emulsifier in processed foods. A 2022 study published in the journal Gastroenterology found that long-term consumption of CMC altered gut microbiome composition and promoted low-grade intestinal inflammation in healthy adults. EFSA is currently reviewing the evidence for emulsifiers more broadly.
Where you find it: Ice cream, salad dressings, processed cheese, baked goods, gluten-free products.
Source: EWG / EFSAHow to check additives on any product
Reading labels manually is time-consuming - especially when additives are listed by their code number rather than their name. SustiScan's ingredient flagging system automatically identifies and classifies every additive in a scanned product, flagging potentially harmful or questionable additives with plain-English explanations and cited research sources.
When you scan a product, SustiScan checks every ingredient against a classification database sourced from EFSA, EWG, and IARC - so you get an immediate, transparent picture of what is actually in the product before you put it in your trolley.
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SustiScan flags harmful and questionable additives with cited research - free to try for 7 days.
Try SustiScan FreeA note on additives and food safety
It is important to note that all additives approved for use in the UK, EU, Australia, and New Zealand have been assessed for safety. A flag on SustiScan does not mean an ingredient is illegal or definitively harmful at normal dietary levels. Food safety science evolves constantly, and the research referenced in this article reflects the current state of published evidence.
If you have specific health concerns related to food additives, consult a registered dietitian or healthcare professional.