E-numbers / Other additives / E916
also: Lautarite (mineral form)
A source of iodine once used to treat flour and strengthen dough. Not a permitted food additive in the UK or EU.
Scan a barcode to check a food for calcium iodate. NutraSafe Pro · £6.99/month · iOS
E916 is not on the UK or EU approved food additives list.
Why it’s worth knowing. E916 is not on the UK or EU approved food additives list. Any product labelled with E916 would be using an unauthorised additive under current UK and EU law.
Calcium iodate is an inorganic salt of calcium and iodate. It is a white crystalline powder that releases iodine. It has historically been used as a flour treatment agent and dough conditioner, and is separately authorised as an iodine supplement in animal feed.
When added to flour, iodate compounds act as oxidising agents that strengthen gluten networks, improving dough handling and bread structure. They also release iodine, which is an essential mineral. In animal feed, calcium iodate is used to meet iodine nutritional requirements in livestock.
E916 is not currently permitted in UK or EU food. In countries where it remains permitted (such as the United States), it has been used in commercial bread, rolls, and flour-based products. On a US label it may appear as 'calcium iodate' in the ingredients list. UK and EU labels should not carry this code.
Calcium iodate releases iodine, which is essential for thyroid hormone production. Both deficiency and excess iodine intake can disrupt thyroid function. High iodine intake from multiple sources, including fortified foods and supplements, can suppress or over-stimulate the thyroid, particularly in people with pre-existing thyroid conditions.
Excessive iodine intake can cause thyroid dysfunction including hypothyroidism and hyperthyroidism, particularly in individuals with underlying thyroid disease.
The UK SACN upper level for iodine intake in adults is 940 micrograms per day; intakes above this from combined dietary sources raise concern for thyroid disruption.
E916 does not appear in Annex II of EU Regulation 1333/2008, which is the Union List of permitted food additives. The UK FSA approved-additives list, derived from that regulation and maintained post-Brexit, also does not include E916 in the food category. Calcium iodate is, however, authorised as an animal feed supplement under separate UK feed additive legislation.
Calcium iodate anhydrous is authorised as a feed additive (nutritional additive, iodine compound) for all animal species under UK feed additive legislation, but does not appear in the UK FSA list of approved food additives.
E916 does not appear in the UK FSA approved food additives and E numbers list; the list moves from E915 to E920 with no entry for E916.
Potassium iodate and calcium iodate were used in some countries as flour improvers from the mid-20th century. JECFA recommended in 1965 that iodate not be used as a flour treatment agent because calculations showed it could result in a daily iodine intake of around 2000 micrograms -- well above the normal daily requirement of 100 to 200 micrograms. Iodate-based flour treatment agents were never included in the EU Union List of permitted food additives established under Regulation 1129/2011, and are not in the current UK permitted list. Several other countries, including Australia and New Zealand, also do not permit their use as flour treatment agents.
JECFA (1965) did not recommend calcium iodate for use as a flour treatment agent, on the basis that use as a dough maturing agent could result in a daily iodine intake of approximately 2000 micrograms, considerably exceeding normal daily requirements.
Because E916 is not permitted in UK or EU food, it should not appear in any product sold under UK or EU food law. People with thyroid conditions are particularly sensitive to excess iodine from any source; they should check iodine content on supplements and imported products. Look for 'calcium iodate' in the ingredients list of any imported goods.
E916 occupies an unusual position: it carries an E-number but is not on the current UK or EU permitted food additives list. The E-number system assigns codes to substances that have been evaluated or were historically used; an E-number alone does not confirm current permission. Calcium iodate's main chemical effect is releasing iodine, which is a genuine nutrient but also one where excess intake causes measurable thyroid disruption. The absence of iodate-based flour treatment agents from the EU and UK permitted lists reflects that concern about cumulative dietary iodine exposure -- a position JECFA established as far back as 1965. In countries where it remains permitted, it is used at low doses. The science on iodine and thyroid function is well established; the question is always about total intake from all sources combined.
E916 is not on the UK FSA's list of approved food additives. It is not permitted for use in food sold in the UK. It is separately authorised as an animal feed supplement, but that is a different regulatory category.
E-numbers are codes assigned to substances that have been evaluated or historically used in Europe. Having a code does not mean a substance is currently permitted. E916 is not included in the active Union List of permitted food additives.
UK and EU food products should not contain E916. In countries where it remains permitted, such as the United States, it has appeared in commercially produced bread and flour-based products as a dough conditioner.
Calcium iodate itself is an inorganic mineral compound and does not derive from animal sources. However, because it is not a permitted food additive in the UK or EU, this question is unlikely to arise for products sold here.
Last reviewed: 20 June 2026
It's the only app that does thisUKJaneK
You Need This AppGmac2005
Best AppGK getting skinny UK App Store reviews
NutraSafe reads the label and puts every additive into plain English, with the source, right in the app.
NutraSafe Pro · £6.99/month · iOS
