Additives

A food additive is any substance not normally eaten on its own that gets added to food during processing. There are around 350 additives approved for use in the UK, each labelled with an "E number" so it can be identified across packaging and across languages. Some are familiar (vitamin C, citric acid, lecithin from soya). Others are synthetic, contested, or carry warning labels. This page explains how the system works, which ones carry real risk, and how to make sense of an ingredients list.

What is an E number?

An E number is the identifier given to a food additive once UK and EU food safety authorities have approved it for use. The "E" stands for Europe. The system was introduced in the 1960s so that an additive could be listed on a label without spelling out the full chemical name, and so that the same substance could be recognised in any member state. E100 to E199 are colours. E200 to E299 are preservatives. E300 to E399 are antioxidants and acidity regulators. E400 to E499 are thickeners, stabilisers and emulsifiers. E500 onwards covers acidity regulators, anti-caking agents, sweeteners, and miscellaneous classes. The number itself tells you nothing about safety. Vitamin C is E300. So is BHA, a synthetic antioxidant linked to cancer in animal studies. The number is just a name.

Why are there additives in food?

Most additives do one of four things. Preservatives stop microbial growth, keeping bread mould-free for weeks and cured meats safe at room temperature. Antioxidants stop fats going rancid, giving crisps and cooking oils a usable shelf life. Emulsifiers and stabilisers stop ingredients separating, which is why a jar of mayonnaise stays smooth and a tub of ice cream stays creamy. Colours and flavour enhancers make a product look and taste the way the manufacturer wants. Some additives serve quieter purposes (humectants stop biscuits drying out, anti-caking agents stop powdered foods clumping, glazing agents make sweets shiny). Without them, modern supermarket food, with its long supply chains and weeks of shelf life, would not be possible in its current form.

Why do we use more food additives now than we used to?

Three things drove the increase. The first is supply chain length. Fifty years ago most food was eaten within days of being made, often within miles of where it was grown. Now a typical loaf of supermarket bread needs to last a week, a ready meal needs to survive a month in a chilled cabinet, and ingredients travel thousands of miles. Preservatives and stabilisers fill that gap. The second is reformulation. Food companies remove sugar, salt and fat to meet public health targets, but the result tastes and feels different to the original product. Sweeteners replace sugar. Gums and starches replace fat. Flavour enhancers compensate for reduced salt. The third is product proliferation. Modern supermarkets stock around 30,000 lines, many of them novel formulations (plant milks, protein bars, sugar-free desserts) that simply did not exist as categories a generation ago, and many of which depend on additives to hold together.

What are food additives used for?

The main classes are:

Colours (E100s) restore or enhance the appearance of processed food. Some are natural (E160a, beta-carotene from carrots; E163, anthocyanins from grapes). Some are synthetic and carry mandatory warnings.
Preservatives (E200s) prevent spoilage by bacteria, yeasts and moulds. Sulphites, sorbates, benzoates and nitrites all fall into this group.
Antioxidants (E300s) stop fats and oils oxidising. Vitamin C and vitamin E are in here. So are synthetic phenolics (BHA, BHT) used in dry cereals and crisps.
Emulsifiers, thickeners and stabilisers (E400s) hold mixtures together. Lecithin in chocolate, pectin in jam, carrageenan in plant milks.
Acidity regulators and anti-caking agents (E500s) control pH and stop powders clumping.
Flavour enhancers (E600s) intensify the savoury notes already present in food. Monosodium glutamate (E621) is the best known.
Sweeteners (E950 onwards) provide sweetness with few or no calories. Aspartame, acesulfame K, sucralose, stevia.

Are food additives bad for you?

The honest answer is "it depends on which one and how much". Every additive permitted for use in UK food has been assessed by the European Food Safety Authority (EFSA) or its UK successor function, and an "acceptable daily intake" (ADI) has been set with a hundredfold safety margin below the level at which any effect was seen in animal studies. For most healthy adults eating a varied diet, exposure stays well below the ADI for almost all additives. That is the regulator's position and it is broadly defensible. There are three reasons to take the question seriously anyway. First, some additives carry mandatory warning labels precisely because regulators decided the public should know (the "Southampton Six" colours and sulphites are the obvious examples). Second, the ADI is calculated per additive, not for the cumulative load of fifteen additives in one ready meal. Third, a small number of additives have been reclassified by international agencies after re-evaluation (aspartame moved into IARC Group 2B in 2023, "possibly carcinogenic to humans"). The cautious position is to know which ones are flagged, and to treat them as a reason to limit, not to panic.

Which food additives carry the most risk?

The additives most worth knowing about, and the basis of the concern flag we put on this site, are:

The Southampton Six colours (E102, E104, E110, E122, E124, E129). Linked to hyperactivity in children by a 2007 University of Southampton study. EU regulation 1333/2008 requires a warning label on any food containing them.
Sulphites (E220 through E228). Mandatory allergen labelling above 10 mg/kg. Trigger asthma attacks in roughly 5 to 10 percent of asthmatic adults.
Nitrites and nitrates in cured meat (E249, E250, E251, E252). Form nitrosamines when heated above around 130 degrees, especially during frying. Processed meat sits in IARC Group 1, "carcinogenic to humans".
Synthetic phenolic antioxidants (E320 BHA, E321 BHT). BHA is in IARC Group 2B and the US National Toxicology Program lists it as reasonably anticipated to be a human carcinogen.
Aspartame (E951). Reclassified by IARC as Group 2B (possibly carcinogenic to humans) in July 2023.
Caramel III and IV (E150c, E150d). Manufacture produces 4-methylimidazole, listed under California's Proposition 65 as a known carcinogen.

None of these are banned in the UK. They are flagged here because they are the additives most likely to be either restricted by other countries, labelled as a warning under UK law, or downgraded by international regulators. If you are scanning a label, those are the names worth recognising.

What are the health implications of eating additives long term?

For an additive at an exposure below its ADI, regulators say the long-term implication is none. The harder question is the cumulative effect of being a heavy consumer of ultra-processed food in general. The 2024 NOVA framework treats additive use as one of the four markers that distinguish ultra-processed food from minimally-processed food. Independent of any single additive, large prospective cohort studies (NutriNet-Santé in France, the EPIC studies in Europe, NHS-II in the US) consistently associate higher ultra-processed food intake with higher rates of cardiovascular disease, type 2 diabetes, certain cancers and all-cause mortality. Whether that association is caused by the additives themselves, or by the sugar, salt, fat and lack of fibre that usually come with them, is still under investigation. The pragmatic answer is that worrying about one E number on the label is less useful than asking whether the food it is in is a regular part of your diet.

How do you know if an additive is dangerous?

Three quick signals on a UK label tell you to look more carefully. First, a warning sentence: "may have an adverse effect on activity and attention in children" means the food contains one of the Southampton Six colours. Second, an allergen statement listing sulphites or sulphur dioxide tells asthmatic readers to avoid it. Third, the product carries a long ingredients list of E numbers in the 100s and 200s rather than a short list of recognisable ingredients, which is the simplest population-level marker of an ultra-processed product. Beyond the label, you can search any E number on this site for the curated risk note where one exists, or use the Food Insight scanner to check a barcode and see the additives flagged automatically.

How do you avoid food additives?

You cannot avoid them entirely without growing your own food, and you would not want to (vitamin C added to bread is technically an additive, and it is good for the bread and good for you). The realistic approach is to reduce exposure to the small subset that carry meaningful risk. Buy plain rather than flavoured versions where you can. Choose unsmoked or uncured meat over bacon and ham when you have the choice. Read the colour declaration on bright drinks and sweets. Pick wines and dried fruits explicitly labelled "no added sulphites" if you are sulphite-sensitive. And, more broadly, lean toward foods with short ingredient lists you recognise. The additives we worry about are concentrated in a fairly narrow slice of the supermarket: brightly coloured drinks and sweets, cured meats, ultra-low-calorie products, and long-life packaged baked goods. Cooking from raw ingredients sidesteps almost all of them.

How we flag risky additives on this site

Our directory below has an entry for every additive currently approved in the UK, around 680 in total. Each entry shows you, where the data is available, what class the additive belongs to, what it is used for, whether it is suitable for vegans, and a brief description sourced from public references. Where the additive is one we have flagged for documented concerns (the categories listed in the section above), the entry carries a coloured risk note at the top citing the basis of the concern (an EFSA re-evaluation, an IARC classification, a regulatory restriction in another jurisdiction). Where we have no documented concern, the entry shows a neutral note explaining that the absence of a flag is not the same as a guarantee of safety, just an absence of red flags in our curated list. We are deliberately conservative: the risk note appears only when there is a citable basis for it.

If you want to check a specific shopping basket, the Food Insight scanner reads barcodes and lists the flagged additives in any product. The food diary tracks what you actually eat over time, with the same flagging applied at the meal level.