Butyric acid and Butyrates
Butyric acid (systematic name butanoic acid), CAS No. 107-92-6, is a naturally occurring short-chain fatty acid. Its name derives from the Latin butyrum ("butter"), reflecting its natural presence in milk fat and dairy products. It is also produced endogenously in the human gut by bacterial fermentation of dietary fibre. This article also covers its mineral salts (sodium, calcium, potassium and magnesium butyrate).
Occurrence and history of use
Butyric acid has been part of the human diet for millennia via dairy consumption, long predating the EU/UK Novel Food reference date of 15 May 1997.
Regulatory status: Butyric acid (free acid)
Not a Novel Food. Butyric acid does not meet the definition of "novel food" under Regulation (EU) 2015/2283 (retained in GB law), because it has a well-documented history of significant consumption in the EU/UK before 15 May 1997.
Supporting evidence:
- Flavouring authorisation: Authorised as a flavouring substance (FL/FLAVIS No. 08.005, CAS 107-92-6) for food use in England, Scotland and Wales under Assimilated Regulation (EC) No 1334/2008, minimum purity 95%, no specified use restrictions.
- Feed additive authorisation: Authorised as a feed additive for all animal species under Council Directive 70/524/EEC, re-confirmed by Commission Implementing Regulation (EU) 2023/1417.
- Absent from novel food registers: Does not appear on the EU Union List of novel foods (Implementing Regulation (EU) 2017/2470) or the GB Register of Novel Food Authorisations.
Regulatory status: Butyrate salts (sodium, calcium, potassium, magnesium)
Status is not clear-cut — treat with more caution than the free acid. No official EU/UK source was found explicitly confirming the mineral salts are, or are not, Novel Food when used as human food supplement ingredients. Unlike the free acid, there is no equivalent flavouring/feed authorisation record establishing a documented pre-1997 history of use in salt form.
- A B2B nutraceutical trade publication describes sodium butyrate's legal status as "ambiguous and fragmented" across EU member states, with the UK FSA now evaluating it under the Novel Food Regulations post-Brexit (substantial equivalence or full safety dossier required).
- Tributyrin analogy: Tributyrin (the natural triglyceride ester of butyric acid, also present in butter) is treated by the EU Novel Food Catalogue as not novel when naturally sourced, but as requiring novel food clearance when produced by chemical synthesis. A 2024 RASFF food-safety alert (notification 2024.8392) flagged a supplement containing tributyrin as an "unauthorised novel food" in an EU member state — indicating production method (natural vs. synthetic) is likely decisive for this substance family.
- Recommendation: before using any butyrate salt, confirm the exact production process with the supplier, check the live EU Novel Food Status Catalogue and GB Register of Novel Food Authorisations for that specific salt, and if in doubt contact FSA's Novel Foods team directly.
Not to be confused with: Beta-hydroxybutyrate (BHB) salts
Beta-hydroxybutyrate (a ketone body) is chemically distinct from butyrate despite the similar name. Sodium/magnesium/calcium BHB salts were the subject of an EFSA novel food safety opinion (applicant Prüvit Ventures Inc., application 28 Feb 2018; proposed as a food supplement/drink-mix ingredient for adults only, max. 6 g/day). EFSA classified it under Article 3(2)(a)(i) of Regulation (EU) 2015/2283 (new/modified molecular structure, no history of use in the EU before 15 May 1997) and concluded in 2022 that the safety of the novel food had not been established, due to inconsistent characterisation, unclear production process and unreliable supporting studies. This is unrelated to butyric acid/butyrate.
References
- FSA — Butyric acid flavouring authorisation (FL 08.005): https://data.food.gov.uk/regulated-products/flavouring_authorisations/08.005
- FSA — Butyric acid feed additive authorisation: https://data.food.gov.uk/regulated-products/feed_authorisations/feedadd-342
- FSA — Register of Novel Food Authorisations guidance: https://data.food.gov.uk/regulated-products/novel_authorisations/guidance
- European Commission — Novel Food status Catalogue: https://food.ec.europa.eu/food-safety/novel-food/novel-food-status-catalogue_en
- European Commission — Union list of novel foods: https://food.ec.europa.eu/food-safety/novel-food/authorisations/union-list-novel-foods_en
- FSA — Novel foods authorisation guidance: https://www.food.gov.uk/business-guidance/regulated-products/novel-foods-guidance
- nmc-magazine.com — Legislative Framework for Sodium Butyrate: https://nmc-magazine.com/legislative-framework-for-sodium-butyrate-food-supplement-or-food-for-special-medical-purposes/
- nutracompliance.com — EU Novel Food Catalogue: January 2025 Updates (tributyrin): https://nutracompliance.com/EU-novel-food-catalogue-updates-january-2025
- RASFF notification 2024.8392 — unauthorised novel food tributyrin: https://webgate.ec.europa.eu/rasff-window/screen/notification/725185
- EFSA Journal 2022;20(9):7449 — Safety of β-hydroxybutyrate salts as a novel food: https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2022.7449