E-numbers / Antioxidants / E300
also: L-ascorbic acid
The same vitamin C that is in oranges, added to stop food browning and losing colour. In fizzy drinks with E211 the two can form traces of benzene.
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Wheat Flour, Water, Yeast, Dried Skimmed Milk, Alcohol, Salt, Wheatgerm, Malted Wheat Flour, Deactivated Yeast, Flour Treatment Agent (Ascorbic Acid).
Ascorbic acid is vitamin C, the vitamin found in citrus fruit, berries and green vegetables.
UK supermarket foods that declare E300: 4,013 of the 43,325 we checked (9.3%)
Counted by its code or its name in the ingredient list.
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
Ascorbic acid is vitamin C, the vitamin found in citrus fruit, berries and green vegetables. The kind used in food is either taken from plants or made from glucose by fermentation. Either way it is the same molecule as the vitamin C in fruit.
It stops oxygen spoiling fats, colours and flavours by reacting with the oxygen first, so it gets used up instead of the food. In bread dough it strengthens the gluten, so the loaf rises more evenly.
Fruit juices, squashes and soft drinks, cured and processed meat (where it slows fat going rancid and helps fix the pink colour from nitrites), jams, tinned and frozen fruit, breakfast cereals, baby food, and bread. Labels call it ascorbic acid, L-ascorbic acid or E300.
In 2026 a NutriNet-Santé analysis of 112,395 French adults found people with more ascorbic acid from additives had 15% more heart and circulation disease. This is about the added preservative, not vitamin C from fruit and vegetables. These are observational studies.
Among 112,395 French adults followed from 2009 to 2024, higher intake of ascorbic acid as an additive was linked to a 15% higher risk of heart and circulation disease.
At gram-sized supplement doses, the body turns some vitamin C into oxalate. Very high intakes are linked to more kidney stones in people prone to them. The NHS advises keeping supplements below 1000mg a day.
Supplements of more than 1000mg of vitamin C a day can raise oxalate in urine and increase the risk of oxalate kidney stones, especially in people who have had them before.
European reviewers set an upper limit of 1000mg a day from all sources, because of stomach upsets and oxalate at higher doses.
When ascorbic acid and sodium benzoate (E211) sit together in an acidic drink, especially with heat and light, they can react to form small amounts of benzene, which causes cancer. UK and EU law do not ban the pairing. The Food Standards Agency worked with makers to change recipes where it found benzene above 10 micrograms per litre.
Benzene can form in soft drinks containing both benzoic acid (E210 or E211) and ascorbic acid (E300) with heat and light. The FSA tested UK soft drinks and worked with industry to bring levels down.
Benzene causes cancer in humans (IARC Group 1). It was first classified in 1982 and reviewed again in 2018.
Daily limit. None set by the international committee or European reviewers. Upper limit from all sources: 1000mg a day (European reviewers, 2006).
People who have had kidney stones, especially calcium oxalate stones, may be told by their doctor to limit high-dose vitamin C supplements. If you want to avoid the benzene pairing, look for ascorbic acid or E300 together with sodium benzoate or E211 on the same drink label.
The kidney stone link appears at gram-sized supplement doses. The real issue is what happens when it sits with sodium benzoate in an acidic drink: the two can form trace benzene. The FSA looked into this in the mid-2000s. If you drink a lot of fizzy drinks and want to avoid the pairing, check the label for both. A large 2026 French study also linked ascorbic acid added to food with 15% more heart and circulation disease.
No. Ascorbic acid is approved in the UK and EU and is on the Food Standards Agency's list.
Yes, when it is with sodium benzoate (E211) in an acidic drink. The FSA found raised benzene in some UK soft drinks in 2006 and worked with makers to bring it down. It only applies when E300 and E211 are on the same label.
Fruit juices, soft drinks, jams, processed and cured meat, tinned fruit, breakfast cereals, bread and baby food. Labels call it ascorbic acid, L-ascorbic acid or E300.
Yes. It is made by fermenting glucose from plants, or from glucose directly, with nothing from animals.
Last reviewed: 9 November 2026
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