Food additives are substances added to products to preserve them, improve texture, enhance flavour, or change appearance. All additives permitted in UK food have been assessed for safety by regulatory bodies. Many are characteristic of ultra-processed (NOVA 4) foods. However, ongoing research continues to examine their effects, and some have attracted more scientific scrutiny than others.
Here are 10 commonly found additives in UK supermarket products, what they do, and what published research has found.
1. Sodium Nitrite (E250)
Found in: bacon, ham, salami, hot dogs, other cured meats
Sodium nitrite prevents the growth of Clostridium botulinum (the bacterium that causes botulism) and gives cured meat its pink colour. The International Agency for Research on Cancer (IARC) has classified processed meat as a Group 1 carcinogen, and nitrites are considered a contributing factor. When heated at high temperatures, nitrites can form nitrosamines, which are known carcinogens in animal studies.
2. Titanium Dioxide (E171)
Found in: some chewing gum, sweets, white sauces, icing
Used as a white colouring agent, titanium dioxide was banned as a food additive in the EU in 2022 following an EFSA assessment that found it could no longer be considered safe, due to concerns about genotoxicity from nanoparticles. As of 2026, the UK FSA has not followed the EU ban and it remains permitted in UK food, though many manufacturers have voluntarily removed it.
3. Artificial Colours: Tartrazine (E102), Sunset Yellow (E110), Carmoisine (E122), Allura Red (E129)
Found in: sweets, soft drinks, some sauces, ice lollies
These synthetic azo dyes have been extensively studied. A 2007 study commissioned by the UK FSA (the "Southampton study") found that mixtures of these colours with sodium benzoate were associated with increased hyperactivity in children. Since 2010, EU law requires products containing these colours to carry a warning label stating they "may have an adverse effect on activity and attention in children." Many UK manufacturers have reformulated to remove them.
4. Potassium Sorbate (E202)
Found in: margarine, soft drinks, cheese, dried fruit, wine
A widely used preservative that prevents mould and yeast growth. Generally considered one of the safer preservatives, with a long history of use. Some in-vitro studies have raised questions about genotoxicity at high concentrations, but regulatory assessments have consistently found it safe at levels used in food.
5. Carrageenan (E407)
Found in: plant-based milks, cream, ice cream, processed meats, infant formula
Extracted from red seaweed, carrageenan is used as a thickener and stabiliser. It has been the subject of ongoing debate. Some animal studies have found that degraded carrageenan (poligeenan) can cause intestinal inflammation, though the food-grade form is different. A 2018 review in the journal Frontiers in Pediatrics raised concerns about its use in infant formula. The Joint FAO/WHO Expert Committee on Food Additives has maintained it as safe for general use but not recommended in infant formula.
6. Monosodium Glutamate — MSG (E621)
Found in: crisps, instant noodles, stock cubes, ready meals, Chinese takeaway food
MSG enhances savoury (umami) flavour. Despite decades of public concern ("Chinese restaurant syndrome"), large-scale scientific reviews, including those by the FDA and EFSA, have found no consistent evidence of harm at normal dietary levels. EFSA established a safe daily intake of 30mg per kg of body weight in 2017. It is one of the most studied food additives and is generally considered safe by major regulatory bodies.
7. Sodium Benzoate (E211)
Found in: soft drinks, salad dressings, pickles, fruit juices, sauces
A preservative that prevents bacterial and fungal growth. The main concern is that when combined with ascorbic acid (vitamin C), it can form benzene, a known carcinogen. This reaction is accelerated by heat and light. The UK FSA tested soft drinks in 2006 and found some exceeded WHO benzene limits, leading to product reformulations. On its own, sodium benzoate is generally considered safe within established limits.
8. BHA and BHT (E320, E321)
Found in: chewing gum, butter, cereals, snack foods, dehydrated foods
Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are antioxidant preservatives that prevent fats from going rancid. IARC has classified BHA as "possibly carcinogenic to humans" (Group 2B) based on animal studies. BHT has shown both pro-oxidant and antioxidant properties in research. Both are permitted in the UK and EU at low levels, but many manufacturers have moved to alternative antioxidants like tocopherols (vitamin E).
9. Polysorbate 80 (E433)
Found in: ice cream, sauces, bakery products, some medicines
An emulsifier that helps oil and water mix. A 2015 study published in Nature found that polysorbate 80 and carboxymethylcellulose altered gut microbiota composition and promoted intestinal inflammation in mice, potentially contributing to metabolic syndrome. However, the concentrations used in the study were higher than typical dietary exposure, and human studies have not confirmed these effects.
10. Phosphoric Acid (E338)
Found in: cola drinks, processed cheese, processed meats
Phosphoric acid gives cola its tangy flavour and acts as a preservative. High phosphate intake has been associated with reduced calcium absorption and bone density concerns in some observational studies, particularly in adolescents who drink large amounts of cola. A 2006 study in the American Journal of Clinical Nutrition found an association between cola consumption and lower bone mineral density in women.
The Bottom Line
All of these additives are legally permitted in UK food and have been assessed by regulatory bodies. "Permitted" means they are considered safe at the levels typically found in food. However, science evolves, and ongoing research continues to refine our understanding of these substances.
IngredScan rates additive risk as low, medium, or high based on current regulatory guidance and published peer-reviewed research. These are relative classifications to help you make informed choices — not definitive safety judgments. When in doubt, scan your products and choose those with shorter ingredient lists and fewer additives you don't recognise.