Some websites claim it is safe, while others claim it can cause heart attacks, kidney and liver failure, and brain problems.
There is a lot of conflicting information about the dangers of propylene glycol.
Some websites claim it is safe, while others claim it can cause heart attacks, kidney and liver failure, and brain problems.
How toxic is propylene glycol?
Propylene glycol has very low toxicity. It has not been found to cause cancer, damage genes or interfere with fertility or reproduction. In addition, there were no recorded reports of deaths.
In rats, the median lethal dose was 9 g/ lb (20 g/kg). Compare this to sugar, which had a lethal dose of 13.5 g/lb (29.7 g/kg), or salt, which was just 1.4 g/lb (3 g/kg) in rats.
After ingesting foods containing propylene glycol, about 45% of the alcohol is excreted by the kidneys as is. The rest breaks down into lactic acid in the body.
When ingested in toxic amounts, lactic acid builds up and can lead to acidosis and kidney failure. Acidosis occurs when the body can't get rid of acid fast enough. It starts to build up in the blood, which interferes with normal function.
The main marker of toxicity is inhibition of the central nervous system. Symptoms include slow breathing, slow heart rate and loss of consciousness.
Poisoning cases can be treated by hemodialysis to remove the substance from the blood or by removing drugs or substances containing propylene glycol.
However, toxicity is very rare. Most cases were due to the use of very high doses of drugs containing propylene glycol or unusual circumstances, such as a man who fell ill and drank the contents of an ice pack.
Is propylene glycol in food dangerous?
Propylene glycol is "generally recognized as safe" (GRAS) by the US Food and Drug Administration (FDA).
In the United States, it can be used as a direct and indirect food additive. In Europe, it is only permitted in food as a solvent for pigments, emulsifiers, antioxidants and enzymes, up to 0.45 g/lb (1 g/kg) in final food.
The World Health Organization recommends a maximum of 11.4 mg of propylene glycol per pound of body weight (25 mg/kg) per day. In the United States, exposure through food is estimated at 15 mg/lb (34 mg/kg) per day.
By comparison, a person with symptoms of poisoning took 213 grams of propylene glycol per day. For a 120-pound (60-kilogram) adult, that's more than 100 times the average diet.
There's only one documented case of food-related toxicity.
A man was found unconscious after drinking a large amount of cinnamon whiskey containing propylene glycol. Although his symptoms were also caused by alcohol, some could be attributed to propylene glycol.
In general, there have been no reports of negative or toxic effects of propylene glycol in food, except in patients with allergies and one case of overconsumption.
However, as current intake estimates are higher than recommended levels, it is advisable to reduce dietary sources as much as possible, especially if the main source is highly processed foods.
