Ascorbic acid (E300)

What it is

Ascorbic acid is vitamin C, used in bakery wares, juices and drinks against oxidation and to treat flour ¹².

EFSA assessed E300 (INS 300) with sodium ascorbate (E301) and calcium ascorbate (E302) ¹.

How often it is used

Ascorbic acid is the fifth most frequent additive in French packaged foods: 7,919 of 126,556 products in 2019 ³.

Of 106,489 French adults, 80.56% consumed it, a mean 15.85 mg/day ⁴.

In the body

The gut absorbs small doses almost fully, large doses less well; the kidneys excrete the excess ¹.

Sodium-dependent transport absorbs up to 98% of low doses, 75% of 1 g and 16% of 12 g ¹. Oxidised ascorbate is reduced back, or degraded irreversibly to mainly oxalate and L-threonate ¹. After injected labelled ascorbate, 44% of urinary radioactivity was recovered as oxalate ⁵. At high doses, intestinal bacteria break down unabsorbed vitamin C ⁵.

Oxidation and breakdown of ascorbate to oxalate

L-Ascorbate
Oxidation by oxygen, metal ions or radicals; reduction by glutathione, NADH or NADPHKeeps vitamin C activity; GLUT1, GLUT3 and GLUT4 move it into cells
Dehydroascorbate
Hydrolysis of the lactone ring, spontaneous or possibly enzyme-catalysedIrreversible; faster at pH 7 to 8 than at pH 3 to 5
2,3-Diketo-L-gulonate
Oxidation, spontaneous or possibly enzyme-catalysedPart is excreted in urine; minor products xylose, xylonate, lyxonate
Oxalate and L-threonate

What studies show

Vitamin C helps iron absorption, and high-dose supplements were linked to kidney stones in men ⁶⁷.

Ascorbate keeps non-haem iron ferrous and raises its absorption 1.5- to 10-fold ⁶. In nitrite-cured meat it can lower nitrosamine levels except NDMA, NPYR, NPIP and NSAR ⁸.

Over a median 11.3 to 11.7 years, stone hazard ratios for total vitamin C of 1,000 mg/day or more, against under 90 mg/day, were 1.43 (95% CI 1.15 to 1.79) in men and 0.99 (0.90 to 1.09) in women ⁹. Over 11 years, Swedish men taking ascorbic acid supplements alone had 310 first stones per 100,000 person-years, non-users 163 (relative risk 1.92, 1.33 to 2.77) ⁷.

With copper or iron ions, ascorbic and benzoic acids can yield traces of benzene, a carcinogen ¹. EFSA found no adverse effects in animals and judged a numerical acceptable daily intake unnecessary ¹.

Regulation

Major jurisdictions permit ascorbic acid, mostly without numerical limits ¹¹⁰¹¹².

Jurisdiction	Rule
European Union	Quantum satis in most foods (2015) ¹
United States	Generally recognised as safe, as preservative and nutrient ¹⁰
Japan	Designated additive ¹¹
China	Quantum satis outside 59 food categories; 0.2 g/kg in wheat flour ²

References

Regulator
EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS). Scientific Opinion on the re-evaluation of ascorbic acid (E 300), sodium ascorbate (E 301) and calcium ascorbate (E 302) as food additives EFSA Journal, 2015.
doi:10.2903/j.efsa.2015.4087
Funding and finding
Funding
European Food Safety Authority, on request from the European Commission (Question Nos EFSA-Q-2011-00470, EFSA-Q-2011-00471 and EFSA-Q-2011-00472), adopted on 14 April 2015. Use levels were provided by FoodDrinkEurope, ICGA, FCRA, Specialised Nutrition Europe, OIV and UNESDA; unpublished toxicity reports were submitted by DSM.
Finding
E 300 (INS 300) is identical to L-ascorbic acid, C6H8O6, 176.12 g/mol. Absorption by sodium-dependent active transport is up to 98% at low doses, 80-90% up to 180 mg, 75% at 1 g and 16% at 12 g; above 80-100 mg/day most further absorbed ascorbate is excreted unchanged in urine. Dehydroascorbic acid can be reduced back to ascorbic acid or irreversibly hydrolysed to diketogulonic acid, oxidised mainly to oxalic and L-threonic acid. Sodium and calcium ascorbate dissociate fully in the stomach. In the presence of copper(II) or iron(III), small amounts of benzene can form from benzoic acid; German non-alcoholic beverages measured in 2010 contained less than the EU drinking-water limit of 1 ug/L. Pro-oxidant and mutagenic effects with redox-active metal ions in some in vitro systems have not been confirmed in vivo. No adverse effects in animal studies at the highest doses tested; bladder tumour promotion by 5% dietary sodium ascorbate in initiated male rats was attributed to sodium. Epidemiology indicated that vitamin C below 1500 mg/day is not a risk factor for kidney stones, although the cited cohort of Taylor et al. (2004) reported a relative risk of 1.41 (95% CI 1.11 to 1.80) in men at 1000 mg/day or more. JECFA allocated a group ADI 'not specified' in 1981; the Panel saw no need for a numerical ADI. In the EU, E 300-302 belong to Group I and are authorised at quantum satis in most foods, with 200 or 300 mg/kg in processed cereal-based foods and baby foods (FCS 13.1.3). In bread, industry reported its function as a flour treatment agent. Fine bakery wares, unprocessed fruit and vegetables, fruit juices and flavoured drinks were the main contributors to additive exposure.
Regulator
National Health Commission of the People's Republic of China; State Administration for Market Regulation. 食品安全国家标准食品添加剂使用标准 (National food safety standard: Standard for uses of food additives), GB 2760—2024 National standard of the People's Republic of China, issued 8 February 2024, in force from 8 February 2025, replacing GB 2760—2014, 2024.
https://file.jgvogel.cn/134/upload/resources/file/595476.pdf
Funding and finding
Funding
Issued by the National Health Commission and the State Administration for Market Regulation; the standard carries no funding statement. The text was read in a copy hosted by a third party, as the issuing bodies' sites refused automated access; its title page, contents and Table A.1 are those of GB 2760—2024.
Finding
Table A.1, ascorbic acid (vitamin C), CNS 04.014, INS 300, functions flour treatment agent and antioxidant: used in various foods in appropriate amounts according to production needs (按生产需要适量使用), except the food categories numbered 1 to 5, 10 to 62 and 68 in Table A.2, which comprise milks, fermented milk, milk powder and cream, butter, fresh fruit, vegetables, fungi and algae, cereals, rice, flours and raw noodles, fresh meat, aquatic products, eggs, sugars, honey, salt, spices, infant formulae and complementary foods for infants, drinking waters, fruit and vegetable juices, tea and coffee; maximum 5.0 g/kg in peeled or pre-cut fresh fruit (04.01.01.03) and in peeled, cut or shredded vegetables (04.02.01.03), 0.2 g/kg in wheat flour (06.03.01) and 1.5 g/kg in fruit and vegetable juices (14.02.01), as ready to drink. Table A.1, sodium carbonate (碳酸钠, CNS 01.302, INS 500(i)), function acidity regulator: according to production needs in various foods except categories 1 to 30 and 33 to 68 in Table A.2, and in fermented rice products; categories 31 and 32 are raw wet and raw dry noodle products. Sodium hydrogen carbonate (碳酸氢钠, CNS 06.001, INS 500(ii)), functions raising agent, acidity regulator and stabiliser: according to production needs in various foods except categories 1 to 56 and 58 to 68 in Table A.2, and in fermented rice products; category 57 is cereal-based complementary foods for infants and young children. Sodium sesquicarbonate (碳酸氢三钠, also named 倍半碳酸钠, CNS 01.305, INS 500(iii)), function acidity regulator: according to production needs in dairy products other than listed exceptions, only goat milk, and in pastries (07.02) and biscuits (07.03). Table A.1, phospholipids (磷脂, CNS 04.010, INS 322), functions antioxidant and emulsifier: according to production needs in various foods, except the categories numbered 1 to 4, 6, 8 to 53 and 59 to 68 in Table A.2, which comprise pasteurised and sterilised milk, fermented milk, milk and cream powder, vegetable oil, animal fats, butter, fresh fruit, vegetables, fungi and algae, cereals, rice, flours and noodle products, fresh, chilled and frozen meat, aquatic products, eggs, sugars, honey, salt, spices, drinking waters, fruit and vegetable juices, wines, and tea and coffee; cream (category 5), hydrogenated vegetable oil (7) and infant formulae and complementary foods for infants (54 to 58) are not among the exceptions. Table A.1, mono- and diglycerides of fatty acids (单,双甘油脂肪酸酯, CNS 10.006, INS 471), functions emulsifier and coating agent (乳化剂、被膜剂): according to production needs in various foods, except the 59 categories numbered 1 to 4, 6 to 11, 13 to 14, 16 to 30, 32 to 53 and 59 to 68 in Table A.2; cream (5), surface-treated fresh fruit (12) and vegetables (15), raw wet noodle products (31) and infant formulae and complementary foods for infants (54 to 58) are not among the exceptions; maximum 20.0 g/kg in butter and concentrated butter (02.02.01.01), 30.0 g/kg in raw dry noodle products (06.03.02.02), 6.0 g/kg in brown sugar, raw sugar, other sugars and syrups (11.01.02) and 5.0 g/kg in spices (12.09). Table A.1, phosphoric acid and phosphates (磷酸及磷酸盐), a group entry that includes disodium dihydrogen pyrophosphate (焦磷酸二氢二钠), tetrasodium pyrophosphate (焦磷酸钠), tetrapotassium pyrophosphate (焦磷酸四钾), trisodium monohydrogen diphosphate (焦磷酸一氢三钠) and calcium acid pyrophosphate (酸式焦磷酸钙); its INS numbers include 450(i), 450(ii), 450(iii), 450(v) and 450(vii); functions water-retention agent, raising agent, acidity regulator, stabiliser, coagulant and anticaking agent (水分保持剂、膨松剂、酸度调节剂、稳定剂、凝固剂、抗结剂). Maximum levels apply singly or in combination, expressed as phosphate (PO4 3-), for example 5.0 g/kg in dairy products other than listed exceptions, 15.0 g/kg in bakery wares (07.0), 5.0 g/kg in prepared and cooked meat products, 20.0 g/kg in non-dairy creamer and compound seasonings and 80.0 g/kg in seasoning packets for instant wet noodles (12.10.01.03); in infant formulae (13.01.01, 13.01.02) and complementary foods for infants and young children (13.02), 1.0 g/kg using only calcium hydrogen phosphate and sodium dihydrogen phosphate.
Independent research
Chazelas E, Deschasaux M, Srour B, Kesse-Guyot E, Julia C, Alles B, et al. Food additives: distribution and co-occurrence in 126,000 food products of the French market Scientific Reports, 2020.
doi:10.1038/s41598-020-60948-w PubMed 32132606
Funding and finding
Funding
PhD grant from Paris 13 University (E. Chazelas); post-doctoral fellowship from the Fondation pour la Recherche Médicale (ARF201809007046, M. Deschasaux); French Ministry of Health (DGS Arrêté 29 Novembre 2019); French National Cancer Institute (INCa_14059); European Research Council (ERC CoG ADDITIVES_864219). Researchers were independent from funders. Funders had no role in the study design, the collection, analysis, and interpretation of data, the writing of the report, and the decision to submit the article for publication. Open Food Facts is a non-profit association.
Finding
53.8% of products contained at least one additive and 11.3% five or more. Appendix 7, products containing each additive: citric acid E 330 18,302; lecithins E 322 13,102; E 14XX modified starches 10,100; sodium carbonates E 500 8587; ascorbic acid E 300 7919; xanthan gum E 415 7327; sodium nitrite E 250 7144; diphosphates E 450 6529; pectins E 440 6504; mono- and diglycerides of fatty acids E 471 6060. Specific starches: E 1442 209, E 1422 173, E 1414 55, E 1450 30, E 1412 27, E 1420 19, E 1404 18, E 1440 5, E 1410 1. The footnote and the Discussion state that the number of products containing each specific modified starch may be underestimated because packaging often states only 'modified starch'. E 500 had the highest squared loading (0.64) in cluster 3, 'stabilizers and emulsifiers mostly used in biscuits and cakes'; sodium carbonate (E 500), diphosphates (E 450) and lecithins (E 322) co-occurred in 1667 products, mostly biscuits. The authors describe E 500, E 450, E 503 and E 422 as widely used in biscuits and cakes as acidity regulators, stabilizers and emulsifiers. Additive doses were not available.
Independent research
Chazelas E, Druesne-Pecollo N, Esseddik Y, de Edelenyi FS, Agaesse C, De Sa A, et al. Exposure to food additive mixtures in 106,000 French adults from the NutriNet-Santé cohort Scientific Reports, 2021.
doi:10.1038/s41598-021-98496-6 PubMed 34608173
Funding and finding
Registration
NCT03335644
Participants
106,489
Funding
NutriNet-Santé: Ministère de la Santé, Santé Publique France, INSERM, INRAE, CNAM and University Sorbonne Paris Nord. E. Chazelas: doctoral funding from University Sorbonne Paris Nord; C. Debras: French National Cancer Institute. Project: European Research Council (Horizon 2020, grant agreement No 864219), French National Cancer Institute (INCa_14059), French Ministry of Health (arrêté 29.11.19) and IdEx Université de Paris (ANR-18-IDEX-0001). Researchers were independent from funders; funders had no role in the study design, the collection, analysis and interpretation of data, the writing of the report, and the decision to submit the article for publication.
In-kind support
Some of the 2677 ad hoc laboratory assays of additive doses were ordered by the consumers' association UFC Que Choisir.
Finding
Intakes of 90 additives were estimated from repeated 24-h records matched to brand-level composition data (OQALI, Open Food Facts, Mintel GNPD), with doses from 2677 laboratory assays, EFSA dose data by food category or Codex GSFA levels; descriptive analyses were weighted to the 2016 French census. Table 1, % consumers; median, 95th percentile and mean (SD) in mg/day; mean (SD) in mg/kg bw/day: modified starches E 14xx 91.48%; 1304.66, 4270.38, 1596.45 (1394.44); 24.33 (21.84). Citric acid E 330 91.15%; 1380.84, 6193.84, 1956.51 (2231.41); 29.84 (34.31). Lecithins E 322 86.57%; 35.36, 168.33, 53.94 (71.99); 0.83 (1.1). Xanthan gum E 415 79.74%; 303.60, 1401.31, 439.26 (508.65); 6.62 (7.62). Mono- and diglycerides of fatty acids E 471 78.07%; 101.90, 547.24, 160.8 (197.42); 2.44 (2.98). Sodium carbonates E 500 67.10%; 560.00, 4950.00, 1267.46 (1913.51); 19.62 (29.73), with median 8.51 and 95th percentile 76.73 mg/kg bw/day. The ADI column reads NA for all six. Diphosphates E 450 64.36%; 62.86, 715.67, 178.33 (308.05); 2.74 (4.67); ADI 40 mg/kg bw/day, exceeded by 0.02% of all participants and 0.03% of consumers. Additives without a specified ADI can be used quantum satis, that is with no limitations other than current good manufacturing practice. The authors state that information on the health impact of regular and cumulative intake of food additives in humans, and on effects of their mixtures, is still missing.
Regulator
EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Scientific Opinion on Dietary Reference Values for vitamin C EFSA Journal, 2013.
doi:10.2903/j.efsa.2013.3418
Funding and finding
Funding
European Food Safety Authority, on request from the European Commission (question EFSA-Q-2011-01229).
Finding
Vitamin C is an essential component of the diet, as humans and other primates have lost the ability to synthesise it. It is a cofactor of monooxygenases, dioxygenases and mixed function oxygenases, reducing the active-centre metal ion and maintaining it in a reduced state. Procollagen-proline dioxygenase and procollagen-lysine 5-dioxygenase require vitamin C for maximal activity, and deficiency impairs the synthesis of collagen, the principal protein of skin, bones, teeth and connective tissues. Scurvy occurs in adults at a plasma ascorbate below 10 umol/L and a body pool below 300 mg, with tooth loss, joint pain, poor wound healing, petechiae, bruising and inflamed, bleeding gums; an intake of 10 mg/day prevents it.
Regulator
EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Scientific Opinion on the substantiation of health claims related to vitamin C and protection of DNA, proteins and lipids from oxidative damage (ID 129, 138, 143, 148), antioxidant function of lutein (ID 146), maintenance of vision (ID 141, 142), collagen formation (ID 130, 131, 136, 137, 149), function of the nervous system (ID 133), function of the immune system (ID 134), function of the immune system during and after extreme physical exercise (ID 144), non-haem iron absorption (ID 132, 147), energy-yielding metabolism (ID 135), and relief in case of irritation in the upper respiratory tract (ID 1714, 1715) pursuant to Article 13(1) of Regulation (EC) No 1924/2006 EFSA Journal, 2009.
doi:10.2903/j.efsa.2009.1226
Funding and finding
Funding
European Food Safety Authority, on request from the European Commission (Question Nos EFSA-Q-2008-916 to -925, -928 to -931, -933 to -936, -2450 and -2451), adopted on 2 July 2009; the version read was published on 9 December 2010 and replaces that of 1 October 2009.
Finding
Dietary iron is absorbed as Fe2+ and not as Fe3+; reducing agents, including vitamin C, promote non-haem iron absorption by keeping it reduced. Inorganic (non-haem) iron absorption is increased 1.5- to 10-fold depending on iron status, the dose of vitamin C and the test meal, although effects on haemoglobin when vitamin C is given with iron are modest. A cause and effect relationship was established between dietary intake of vitamin C and increased non-haem iron absorption.
Independent research
Thomas LD, Elinder CG, Tiselius HG, Wolk A, Akesson A. Ascorbic acid supplements and kidney stone incidence among men: a prospective study JAMA Internal Medicine, 2013.
doi:10.1001/jamainternmed.2013.2296 PubMed 23381591
Funding and finding
Participants
23,355
Follow-up
11 years; first incident stones ascertained from registries, 1 January 1998 to 31 December 2009
Funding
The research was funded by the Swedish Research Council/Research Infrastructures (grant No. 2008-5947) and Karolinska Institutet KID funding (PhD funding awarded to Ms Thomas). Role of the Sponsors: The funders had no role in the design and conduct of the study; in the collection, analysis, and interpretation of the data; or in the preparation, review, or approval of the manuscript.
Finding
First incident kidney stones: 31 of 907 users of ascorbic acid only (9,995 person-years; 310 per 100,000 person-years) against 405 of 22,448 supplement non-users (248,884 person-years; 163 per 100,000); incidence rate difference 147 per 100,000 person-years. Multivariable relative risk 1.92 (95% CI 1.33 to 2.77); fewer than 7 tablets a week 1.66 (0.99 to 2.79), 7 or more 2.23 (1.28 to 3.88), p for trend 0.001. Multivitamin use only: relative risk 0.86 (0.62 to 1.19).
Regulator
EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS), Mortensen A, Aguilar F, Crebelli R, Di Domenico A, Dusemund B, et al. Re-evaluation of potassium nitrite (E 249) and sodium nitrite (E 250) as food additives EFSA Journal, 2017.
doi:10.2903/j.efsa.2017.4786 PubMed 32625504
Funding and finding
Funding
European Food Safety Authority; requestor: European Commission (Question numbers EFSA-Q-2011-00460 and EFSA-Q-2011-00461).
Finding
Sodium and potassium nitrite are used in curing mixtures to develop and fix the colour of meat, to inhibit microbial growth and to develop characteristic flavours. Acceptable daily intake 0.07 mg nitrite ion/kg body weight per day, based on methaemoglobin formation. Use as food additives supplied about 17% (range 1.5 to 36.0%) of overall nitrite exposure. Margin of exposure for endogenous NDMA formed from nitrite at the ADI 4.2 × 10^5; for preformed NDMA plus NDEA in processed food, below 10,000 in all age groups at high exposure. Nitrosamines formed from nitrite added at authorised levels could not be clearly distinguished from those present without added nitrite. There was evidence linking preformed NDMA with colorectal cancer and some evidence linking nitrite plus nitrate from processed meat with colorectal cancer.
Independent research
Ferraro PM, Curhan GC, Gambaro G, Taylor EN. Total, Dietary, and Supplemental Vitamin C Intake and Risk of Incident Kidney Stones American Journal of Kidney Diseases, 2016.
doi:10.1053/j.ajkd.2015.09.005 PubMed 26463139
Funding and finding
Participants
197,271
Follow-up
median 11.7 years (NHS I), 11.5 years (NHS II) and 11.3 years (HPFS)
Funding
This study was supported by research grants from the National Institutes of Health: DK094910, DK91417, CA186107, CA176726 and CA167552. The funders of this study had no role in study design; collection, analysis, and interpretation of data; writing the report; and the decision to submit the report for publication.
Finding
6,245 incident stones over 2,494,789 person-years. Men (HPFS), total vitamin C of 1,000 mg/day or more against less than 90 mg/day: 260 cases in 81,316 person-years against 157 in 45,363; age-adjusted HR 0.98 (95% CI 0.80 to 1.20), multivariable HR 1.43 (1.15 to 1.79), p for trend 0.005; the change was due predominantly to adjustment for potassium intake. Supplemental vitamin C of 1,000 mg/day or more in men: HR 1.19 (1.01 to 1.40). Women (NHS I and II pooled), 1,000 mg/day or more: 257 cases in 179,051 person-years against 661 in 318,326; multivariable HR 0.99 (0.90 to 1.09). Dietary vitamin C was not associated with stones in either sex, although few participants had dietary intakes above 700 mg/day. Urinary oxalate after vitamin C loading may be inflated by ex vivo non-enzymatic conversion of vitamin C to oxalate.
Regulator
US Food and Drug Administration. Ascorbic acid, 21 CFR 182.3013 and 182.8013: substances generally recognized as safe Code of Federal Regulations, title 21, part 182, subpart D (Chemical Preservatives) and subpart I (Nutrients), read in the electronic Code of Federal Regulations, up to date as of 20 October 2026, 2026.
https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-182
Funding and finding
Funding
US Food and Drug Administration; the text is federal regulation codified by the Office of the Federal Register.
Finding
Sections 182.3013 (chemical preservatives) and 182.8013 (nutrients) each list ascorbic acid and state: 'This substance is generally recognized as safe when used in accordance with good manufacturing practice.'
Regulator
Ministry of Health, Labour and Welfare; Consumer Affairs Agency. 第10版食品添加物公定書 (Japan's Specifications and Standards for Food Additives, 10th edition) Ministry of Health, Labour and Welfare and Consumer Affairs Agency, Japan; Appendix 1, classification table of listed additives, and Section F, standards for use, 2024.
https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/kenkou_iryou/shokuhin/syokuten/kouteisho10e.html
Funding and finding
Funding
Ministry of Health, Labour and Welfare and Consumer Affairs Agency, Japan; the compendium carries no funding statement.
Finding
Appendix 1 classifies L-ascorbic acid (Ｌ－アスコルビン酸, code FA001100) as a designated additive (指定), the category listed in Appended Table 1 of the Food Sanitation Act Enforcement Regulations; calcium and sodium L-ascorbate, L-ascorbic acid 2-glucoside and the stearate and palmitate esters are also designated. Section F, standards for use, has entries for erythorbic acid and sodium erythorbate and none for L-ascorbic acid or its salts. Appendix 1 classifies グリセリン脂肪酸エステル (Glycerol Esters of Fatty Acids, code FA018600) as designated; the Section D monograph (https://www.mhlw.go.jp/content/11130500/001208483.pdf) defines it as esters of fatty acids with glycerol or polyglycerol and their derivatives, comprising glycerol fatty acid esters, glycerol acetic, lactic, citric, succinic and diacetyltartaric acid fatty acid esters, glycerol acetic acid esters, polyglycerol fatty acid esters and polyglycerol condensed ricinoleic acid esters.

Updated 2026-10-21