It has been shown that a preservative commonly used to prevent mold in food increases weight gain and glucose production in mice and increases the risk of diabetes in humans.
In an article published in the journal Science Translational Medicine, a team of scientists led by endocrinologist Amir Tirosh from the Sheba Medical Center in Israel reports on experiments on mice and a clinical pilot study. Both studied the metabolic effects of a preservative known as propionate.
The substance is a naturally occurring short-chain fatty acid. It is common in the human gut and is produced by resident bacteria in response to the presence of carbohydrates.
As calcium propionate, it is used as a preservative in many commercially produced foods, especially bread and other baked goods, processed meat and dairy products. Its main purpose is to limit the development of fungal colonies. On the packaging it is known as E282.
Tirosh and colleagues exposed mice to significant doses of the substance and found that this triggered glycogenolysis – glucose production – and hyperglycemia, high blood sugar, the defining characteristic of diabetes.
A follow-up study on humans revealed that exposure to propionate increased insulin resistance. However, the number of people in the study was too small to draw final conclusions.
The results, especially if confirmed in larger studies, could lead to significant changes in food production.
"Our findings could affect the current practice of food preservation," the researchers write.
"Given that the US Food and Drug Administration has declared Propionate to be widely accepted and has no known adverse effects, there are currently no restrictions on its use, except as required by good manufacturing practice . "
Tirosh and colleagues note that in the human study in which subjects were exposed to propionate concentrations similar to those in preserved foods, the hyperglycemic response was lower than in the mice administered proportionately higher doses.
However, they point out that concerns about "repeated daily exposure" could be at acceptable levels in the food industry.
"There are alternatives that could be used to conserve food, and if these molecules prove neutral in their metabolic activities, simple changes in manufacturing practices can be beneficial to public health," they conclude.