What Is Propylene Glycol in Food? Is It Safe?

What is propylene glycol? Why is propylene glycol added to many food products, such as cupcakes, in our daily life? Can long-term consumption of this substance really cause kidney diseases?

Widely used in food, medicine and cosmetics

Propylene glycol is a kind of food additive, which can play the role of emulsification, stabilisation and coagulation.

Propylene glycol is an organic compound, usually a slightly sweet, odourless, colourless, transparent, oily liquid, hygroscopic and easily mixed with water, acetone and chloroform. Its viscosity and hygroscopicity are good and it is widely used in food, pharmaceutical and cosmetic industries.

In the food industry, propylene glycol is mainly used as an emulsifier in food additives, and is an excellent solvent for flavourings and colourings. In the pharmaceutical industry, propylene glycol is commonly used in the manufacture of various types of ointments, ointment solvents, softeners and so on. In addition, propylene glycol is also used as a solvent and softener for cosmetics.

Propylene glycol functions as a stabiliser and coagulant, anti-caking agent, thickener, etc. The maximum use level of propylene glycol in confectionery is 3 g/kg. The safety standard for propylene glycol established by JECFA is an intake of not more than 25 mg/kg body weight per day.

With regard to the toxicity of propylene glycol, most of the current reports refer to kidney damage in animals. If the dosage data from animal toxicological experiments are extrapolated to a 100-fold safety factor for human beings, an adult with a body weight of 60 kg would have to consume 12 g of propylene glycol per day in order to cause toxicity. On this basis, 4kg of cake with acceptable levels of propylene glycol would need to be consumed per day.

The International Joint Expert Group on Food Additives (JEGFA) has set a safety standard for propylene glycol: a daily intake of no more than 25mg per kilogram of body weight. Calculated on the basis of a body weight of 60kg, this equates to a daily intake of no more than 1.5g, and there is no problem with eating it every day. Therefore, for pastries that comply with the national standard (use no more than 3 g/kg), eating one kilogram per day can keep the intake of propylene glycol within the safe range.