April 24, 2019

expert reaction to study linking a food preservative to altered metabolism and insulin resistance

Research published in Science Translational Medicine shows that propionate, a common food preservative, increased weight gain and glucose production in mice and insulin resistance in humans.

Prof Keith Frayn, Emeritus Professor of Human Metabolism, University of Oxford, said:

“These authors have tested the effects of calcium propionate, a common food additive used to prevent mould growth, also known as E282. They suggest that this compound raises blood glucose concentration, potentially increasing diabetes risk. Propionate is a normal constituent of human blood. It is produced in humans by bacterial action on fibre in the colon, and there is much evidence that increased fibre intake, accompanied by increased concentrations of propionate and other ‘volatile fatty acids’ in the blood, has beneficial effects on metabolism.

“So this study raises the question of whether propionate taken by mouth, rather than produced normally in the colon, has different, adverse effects. The study appeared to be of high quality in mice, but the human data were less convincing. The authors seem to show an adverse metabolic effect with a minimal rise in the concentration of propionate in the blood, much less than is seen after supplementation of the diet with extra fibre. This suggests that more research in humans would be needed before condemning use of propionate as a food additive.”

‘The short-chain fatty acid propionate increases glucagon production and insulin resistance in mice and humans’ by Tirosh et al. was published in Science Translational Medicine at 19:00 UK time on Wednesday 24 April.

Declared interests:

Prof Keith Frayn: “I have no conflict of interest to declare.”