Calcium propionate
A preservative added to bread and baked goods to stop mould growing. It is the calcium salt of propionic acid, which also occurs naturally in some cheeses.
Some studies link regular intake to irritability, restlessness, inattention and sleep disturbance in children. Propionic acid, which the body releases from this additive, has been shown to cause autism-like behavioural and brain changes in animal studies.
What is it?
The calcium salt of propionic acid, a short-chain fatty acid that occurs naturally in Swiss-type cheeses and as a product of gut bacterial fermentation. In food manufacturing it is produced synthetically by neutralising propionic acid with calcium hydroxide or calcium carbonate.
What does it do?
Inhibits the growth of moulds and certain bacteria by disrupting their ability to take up nutrients and reproduce. It is effective at the slightly acidic pH of bread dough, where it slows spoilage without significantly affecting yeast activity during baking.
Where you will see it
Most common in prepacked sliced bread, including wholemeal and seeded varieties, partially baked breads, rolls, tortilla wraps, pitta bread, rye bread, and some fruit cakes and bakery products. On UK ingredient labels it appears as 'calcium propionate' or 'E282'.
What the science says
Behavioural effects in children
A double-blind crossover trial found that some children consuming calcium propionate in bread showed increases in irritability, restlessness, inattention and sleep disturbance compared with those eating preservative-free bread. Removing it reversed these effects in the affected group. The researchers noted that the proportion affected was a subset, not all children.
In a double-blind crossover study, children eating bread containing calcium propionate showed more irritability, restlessness, inattention and sleep disturbance than those eating preservative-free bread, with effects reversing on withdrawal.
Propionic acid, the gut and the brain
When calcium propionate is digested, it releases propionic acid. Animal studies have shown that propionic acid infused directly into rodent brains produces behavioural changes resembling autism spectrum disorder (ASD), along with inflammatory markers and altered gene expression. Separately, children with ASD are known to have elevated propionic acid produced by gut bacteria. The animal evidence is direct-dose at high levels, not a dietary exposure study, so the relevance to ordinary bread consumption is uncertain.
Intraventricular infusion of propionic acid in rats produced repetitive movements, social deficits and brain inflammatory markers consistent with autism-like behaviour.
Propionic acid induced behavioural effects of relevance to autism spectrum disorder in the hole board test in rats, including altered locomotion and social interaction.
Prenatal exposure to calcium propionate in mice altered offspring brain gene expression and produced behaviour consistent with autism spectrum disorder.
Migraine and neurological sensitivity
Propionate is listed among dietary triggers reported by some migraine sufferers in observational studies. The mechanism is thought to involve vasodilation, though the evidence comes from self-reported dietary logs and small observational cohorts rather than controlled trials.
Propionate-containing foods appear in lists of self-reported dietary migraine triggers in observational surveys of migraine patients.
Metabolic effects
A study in mice found that dietary propionate activated a stress-signalling cascade that raised blood glucose and insulin levels, suggesting a possible mechanism linking preservative exposure to metabolic disruption. The doses used and the differences between mouse and human metabolism mean the direct relevance to human dietary intake is not established.
In mice, dietary propionate activated a glucagon and adrenocorticotropic hormone cascade, raising blood glucose and insulin resistance markers.
Where it stands with the regulators
Who should be careful
Parents of children who notice irritability, sleep disruption or inattention after eating commercial bread may wish to trial preservative-free or sourdough bread and compare. People who identify propionate as a migraine trigger should look for 'calcium propionate' or 'E282' on ingredient labels. Prepacked bread is the main exposure route.
The honest read
The regulatory picture is clear: E282 is fully permitted in UK and EU bread, and EFSA found no safety concern at typical intake levels. The science picture is less settled. The 2002 Dengate double-blind trial in children is real, the animal studies linking high-dose propionic acid to autism-like brain changes are real, and the 2019 Science Translational Medicine mouse study on metabolic effects is real. What none of these studies have established is whether the quantities of propionate released from eating ordinary commercial bread are sufficient to produce these effects in most people. The behavioural RCT is a single study with a subset of affected children. The animal studies used direct-dose methods that do not map cleanly onto dietary exposure. The science is live: there are legitimate open questions, particularly around children and regular high intake.
Related additives
Common questions
Is E282 banned in the UK?
No. E282 is on the UK FSA approved-additives list and is permitted in prepacked bread, rolls, tortilla, pitta and rye bread under assimilated EU Regulation 1333/2008.
Can calcium propionate affect children's behaviour?
One double-blind crossover trial (Dengate & Ruben, 2002) found that a subset of children eating bread containing calcium propionate showed more irritability, restlessness and sleep disturbance than those eating preservative-free bread. Effects reversed when the additive was removed. This is one study; the finding has not been replicated in a large multi-centre trial.
What foods contain E282?
Mainly prepacked sliced bread, rolls, tortilla wraps, pitta and rye bread sold in UK supermarkets. Sourdough bread and bread sold without packaging (baked fresh in-store) typically does not contain it. Check the ingredient list for 'calcium propionate' or 'E282'.
Is E282 vegan?
Yes. Calcium propionate is produced synthetically and does not involve animal-derived ingredients. It is suitable for vegans and vegetarians.
Sources
- FSA Approved Additives and E Numbers
- FSA Regulated Products Register: E282
- Dengate S, Ruben A. Controlled trial of cumulative behavioural effects of a common bread preservative. Journal of Paediatrics and Child Health, 2002
- MacFabe DF et al. Neurobiological effects of intraventricular propionic acid in rats: possible role of short chain fatty acids on the pathogenesis and characteristics of autism spectrum disorders. Behavioural Brain Research, 2007
- Abdelli LS, Samsam A, Naser SA. Propionic acid induces gliosis and neuro-inflammation through modulation of PTEN/AKT pathway in autism spectrum disorder. Scientific Reports, 2019
- Tirosh A et al. The short-chain fatty acid propionate increases glucorticotropic hormone and hyperglycaemia via a gut-brain neural circuit. Science Translational Medicine, 2019
- EFSA ANS Panel opinion on propionic acid, sodium propionate, calcium propionate and potassium propionate (E280-E283), 2014
- Choi J et al. Propionic acid induced behavioural effects of relevance to autism spectrum disorder evaluated in the hole board test with rats. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 2018
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