Sodium, potassium and calcium salts of fatty acids
Soap-like salts made from common dietary fats, used to stop ingredients clumping and help powders flow freely.
What is it?
E470a is a group of metallic salts formed by reacting fatty acids (principally palmitic, stearic, oleic and myristic acids, the same fats found in vegetable oils and animal fats) with sodium, potassium or calcium. The result is a dry, waxy or powdery substance chemically similar to soap. The raw fatty acids are the same ones the body metabolises from ordinary dietary fat.
What does it do?
In the gut, these salts split back into their component fatty acid carboxylates and their cations (sodium, potassium or calcium ions), all of which are handled through normal digestion. In food manufacturing they act as anti-caking agents, keeping powders free-flowing, and as emulsifiers or lubricants in baked goods and coatings. They also coat surfaces to reduce sticking and can stabilise fat-based mixtures.
Where you will see it
Most commonly found in cake mixes, bread improvers, dried powdered soups and sauces, chewing gum base, seasonings, spice blends, and as a coating or release agent on sweets and confectionery. Occasionally in dietetic foods and supplements in powder or tablet form. On a label it appears as 'E470a', 'sodium salts of fatty acids', 'potassium salts of fatty acids', or 'calcium salts of fatty acids'.
What the science says
Digestion and metabolism
E470a dissociates in the gastrointestinal tract into fatty acids and their corresponding mineral cations. These are absorbed and metabolised through the same pathways as dietary fat and minerals. Because the constituent fatty acids (palmitic, stearic, oleic, myristic) are normal components of the human diet, intake from food additive use adds only a small contribution alongside naturally occurring dietary fat.
The EFSA Panel on Food Additives concluded that E470a is expected to dissociate in the gastrointestinal tract to fatty acid carboxylates and the corresponding cations, both of which are normal constituents of the diet and are handled by ordinary metabolic pathways.
Regulatory safety assessment
EFSA completed a full re-evaluation of E470a in 2018 as part of a systematic programme reviewing all approved EU food additives. The panel found no toxicological concern at reported use levels. No numerical ADI was considered necessary because the constituents are ordinary dietary components metabolised through well-characterised routes. The original 'not specified' ADI set by the Scientific Committee on Food in 1991 was maintained.
In 1991 the Scientific Committee on Food set a group ADI of 'not specified' for the fatty acids myristic, stearic, palmitic and oleic acid and their salts. The 2018 EFSA re-evaluation maintained this position and concluded there was no safety concern at reported uses and use levels.
There were no data available on subchronic toxicity, chronic toxicity, or reproductive and developmental toxicity specifically for the metallic salts of fatty acids. EFSA noted this data gap but considered it adequately covered by the known metabolism of the constituent fatty acids.
Where it stands with the regulators
Who should be careful
People who avoid animal-derived ingredients should check the source: E470a can be derived from animal fats (such as tallow) or from vegetable oils. The label entry 'E470a' does not specify the source. Anyone keeping strictly vegan or halal/kosher will need to contact the manufacturer to confirm the origin of the fatty acids used.
The honest read
E470a is one of the more straightforward additives on the UK-approved list. Its building blocks are the same fatty acids found throughout a normal diet, and both the original 1991 assessment and the 2018 EFSA re-evaluation reached the same conclusion. The one honest caveat from the 2018 review is an absence of specific long-term toxicity studies on the salt forms themselves, though EFSA considered this covered by the well-understood metabolism of the constituent fatty acids. For most people the practical question is not about toxicology but about the source: animal fat or vegetable oil. The label does not tell you which.
Related additives
Common questions
Is E470a banned in the UK?
No. E470a is on the UK FSA's list of approved additives and remains permitted under assimilated EU Regulation 1333/2008. There are no UK or EU restrictions or bans.
Is E470a vegan?
Not necessarily. The fatty acids used to make E470a can come from animal fats (such as tallow or lard) or from plant-based vegetable oils such as palm or sunflower. The E-number alone does not indicate which source was used. Contact the manufacturer if you need to confirm the origin.
What foods contain E470a?
E470a is mainly found in cake mixes, bread improvers, dried powdered soups and sauces, seasoning blends, chewing gum, and confectionery coatings. It may also appear in dietary supplements in tablet or powder form, where it acts as a flowing agent or lubricant.
What does 'ADI not specified' mean for E470a?
It means regulators did not consider it necessary to set a numerical daily limit. The constituent fatty acids (palmitic, stearic, oleic, myristic) are already present in ordinary food in far larger quantities than any additive use would contribute, so a specific cap was not thought meaningful. It does not mean the additive is unregulated; it is still only permitted in specific food categories and at levels no higher than needed to do the job.
Sources
- Re-evaluation of sodium, potassium and calcium salts of fatty acids (E 470a) and magnesium salts of fatty acids (E 470b) as food additives - EFSA Journal 2018
- Re-evaluation of E470a and E470b - PubMed Central full text
- UK FSA Approved Additives and E Numbers
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