Canadian autism researchers have shown that higher than normal levels of propionic acid can accumulate in the circulating blood, cross the gut-blood and blood-brain barriers and can concentrate inside the cells where they may have adverse effects on brain development and function. In recent studies, brief infusions of propionic acid in rats produced short bouts of behavioral (hyperactivity, perserveration, object fixation, social impairments) and other effects such as seizures , similar to those seen in Autistic Spectrum Disorders (Thomas et al 2012, Ossenkopp et al 2012, McFabe et al 2011, Thomas et al 2010, Shutlz et al 2009, Shultz et al 2008, McFabe et al 2007).
The EFSA ANS Panel provides a scientific opinion re-evaluating the safety of propionic acid (E 280), sodium propionate (E 281), calcium propionate (E 282) and potassium propionate (E 283) which are authorised as food additives in the EU and have been previously evaluated by the SCF and JECFA. JECFA allocated an ADI “not limited”. The SCF concluded that potassium propionate could be added to the list of preservatives and established an ADI ”not specified”. Propionates are naturally occurring substances in the normal diet. The Panel considered that forestomach hyperplasia reported in long-term studies in rodents is not a relevant endpoint for humans because humans lack this organ. Based on the reported presence of reversible diffuse epithelial hyperplasia in the oesophagus the LOAEL for a 90-day study in dogs was considered by the Panel to be 1 % propionic acid in the diet and the NOAEL to be % propionic acid in the diet. The Panel considered that there is no concern with respect to genotoxicity and carcinogenicity. The Panel concluded that the present database did not allow allocation of an ADI for propionic acid - propionates. The overall mean and 95 th percentile exposures to propionic acid - propionates resulting from their use as food additives (major contributor to exposure) ranged from - and - mg/kg bw/day, respectively. The Panel noted that the concentration provoking site of contact effect in the 90-day study in dogs (1 % propionic acid in the diet) is a factor of three higher than the concentration of propionic acid - propionates in food at the highest permitted level and concluded that for food as consumed, there would not be a safety concern from the maximum concentrations of propionic acid and its salts at their currently authorised uses and use levels as food additives.