What to Know About Propylene Glycol in Foods

The food you buy from grocery stores can contain many ingredients. Some additives enhance flavor, while others help in food preservation. One common ingredient is propylene glycol, primarily found in salad dressing. It's also present in many cosmetics, dog food, and hygiene products.

What Is Propylene Glycol?

Propylene glycol is a colorless, nearly odorless, thick liquid. It has a variety of uses beyond being a food additive. It's used in many products because it helps them maintain their consistency, moisture, and texture. 

Propylene glycol also has other names, including:

  • Trimethyl glycol
  • Methyl ethyl glycol
  • Dihydroxypropane
  • Propanediol

Sometimes people confuse it with ethylene glycol. They both have low melting points and are used in antifreeze, but they’re not the same.

The product comes in various grades for use in different applications. Apart from being used as a food additive, propylene glycol is also an active ingredient in engine coolants, airplane deicers, enamels, paints, varnishes, and polyurethane cushions.

Propylene glycol has been found in some of the most hazardous waste sites in the country, but in normal amounts, it’s not considered unsafe. But the fact that it’s also an ingredient in antifreeze raises concerns about the possible side effects of eating any food contaminated with it.

Foods that Contain Propylene Glycol

Propylene contains many properties that are beneficial to packaged foods. Many food manufacturers use it to lengthen the shelf life of their processed foods. Examples of packaged foods that contain the product include:

  • Seasoning blends
  • Dried soups
  • Salad dressings
  • Baking mixes for foods like cakes, muffins, cinnamon buns, biscuits, cupcakes, and pancakes
  • Powdered drink mixes
  • Flavored teas
  • Soft drinks
  • Alcoholic beverages
  • Food coloring
  • Flavoring extracts
  • Highly processed snacks
  • Fast foods
  • Flavored popcorn
  • Cake frosting
  • Ice cream flavors
  • Mass-distributed baked desserts
  • Marshmallows
  • Dried coconut shreds
  • Sauces
  • Sour cream
  • Potato salad
  • Macaroni
  • Cheese

Apart from using it as a preservative and flavor enhancer, food manufacturers also use propylene glycol as an emulsifier, a texturizer, and a processing aid to enhance food's appearance.

Potential Health Risks of Propylene Glycol in Food

People against the use of propylene glycol in food argue that its levels in food are beyond what the World Health Organization recommends. According to the World Health Organization, the acceptable amount is a maximum of 25 milligrams of propylene glycol per kilogram of your body weight.

Continued

Toxicity from propylene glycol is rare. Some people still recommend reducing your dietary sources of it, citing the following potential health risks:

Worsened kidney and liver disease symptoms: If you have normal liver and kidney function, your body can easily remove propylene glycol. About 45% of the compound gets out of the body through the kidneys unchanged. The body breaks down the rest into lactic acid.

In large quantities, lactic acid can build up and lead to kidney failure and acidosis. Acidosis means your body can’t remove the acid as fast as it should, leading to toxicity. If you have kidney or liver disease, the process of eliminating the compound is also slow. The main sign of toxicity is depression of your central nervous system, causing a low heart rate, slow rate of breathing, and loss of consciousness.

Allergic reactions: A small number of people are allergic to propylene glycol. The most common signs are skin reactions, dermatitis, and a rash on the face or the whole body.

Increased risk of a heart attack: When propylene glycol is injected in high amounts, it leads to rapid heart rate, heart rhythm problems, or low blood pressure

How to Avoid Propylene Glycol in Your Food

Most processed foods contain at least some propylene glycol. While it is a low-toxicity substance, you may develop health complications if you eat foods that have it in large quantities. The best way to protect yourself is to avoid products that contain the substance. Instead, eat more fresh whole foods.

WebMD Medical Reference Reviewed by Melinda Ratini, DO, MS on June 17, 2021

Sources

SOURCES:

ACDSCAMP: “Propylene Glycol.”

ACS Publications: “Process Designs for Converting Propylene Glycol to Acrylic Acid Via Lactic Acid and Allyl Alcohol.”

Agency for Toxic Substances and Disease Registry: “PROPYLENE GLYCOL.”

American Journal of Clinical Pathology: “Rapid and Specific Quantification of Ethylene Glycol Levels: Adaptation of a Commercial Enzymatic Assay to Automated Chemistry Analyzers.”

Case Reports in Endocrinology: “Acute Renal Failure Secondary to Inadvertent Propylene Glycol Overdose with Single-Day High-Dose Vitamin D (Stosstherapy).”

EFSA Journal: “Re‐evaluation of propane‐1,2‐diol (E 1520) as a food additive.”

Encyclopedia of Toxicology: “Vitamin A.”

Flavor Science: “Reactions of Propylene Glycol with the Constituents of Food Flavorings.”

International Journal of Toxicology: “Safety Assessment of Propylene Glycol, Tripropylene Glycol, and PPGs as Used in Cosmetics.”

Journal of the American Academy of Dermatology: “Propylene glycol dermatitis.”

Journal of the American College of Toxicology: “Final Report on the Safety Assessment of Propylene Glycol Stearate and Propylene Glycol Stearate Self-Emulsifying.”

Journal of Toxicology: Clinical Toxicology: “Unusual D-Lactic Acid Acidosis from Propylene Glycol Metabolism in Overdose.”

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The Agency for Toxic Substances and Disease Registry: "Toxicological Profile for Propylene Glycol." 

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