Are You Anti-Antifreeze? Read This

By Josh Bloom — Jan 25, 2016
Environmental activists often claim that there is antifreeze in some food. They are not wrong, but they make it sound harmful. Instead, it is even kosher. Maybe they don't know the difference, but you will after reading this article.

antAll antifreezes are not created equal.

Actually, that should read "both antifreezes are not equal," since there are only two that are commonly used (but that's a terrible lead). Yet those two act alike, they sound alike, they even taste alike, but they could not be more different and in that difference is another way where environmental activists get so much wrong about chemicals.

The difference is due to a single carbon atom, which makes one a poison and the other a food. Because of that, sometimes activists claim dangerous antifreeze is in food. Yes, environmentalists get organic chemistry wrong. Ain't science great?

One of the two antifreeze chemicals, ethylene glycol, is the poison, the one that can kill your pets if they drink enough of it. It has been the most commonly used antifreeze but is being replaced by the other one, propylene glycol.

They are similar:


The additional carbon on propylene glycol makes all the difference in the world. It is so non-toxic that you can drink a glass of it. If this doesn't sound kosher to you, it should, because it is kosher. The chemical company Sigma-Aldrich sells kosher propylene glycol, as do many other companies. It is so safe that it is a common food additive.

The CDC agrees:

  • No studies were located regarding death in humans after oral exposure to propylene glycol.
  • A fatal case of propylene glycol poisoning occurred in a horse given 3.8 L of propylene glycol (one gallon) instead of mineral oil. The horse died of respiratory arrest 28 hours after administration.

Environmentalists often confuse the food additive with ethylene glycol, which does cause poisoning, although it takes a lot to cause harm compared to more potent toxins, such as cyanide, arsenic or nicotine. Ethylene glycol itself is not toxic, but it is converted in the liver into two toxic metabolites, oxalic acid and glycolic acid. Oxalic acid is the major component of kidney stones, and is crystalline and very insoluble. It crystallizes in the kidneys.

The reason that ethylene glycol is such a problem for pets is unique. It is sweet (both antifreezes are sugar alcohols the simplest sugars) and therefore they taste good. So, while pets and children might try another poison, it will taste icky, and they will often spit it out. This is clearly not the case with the antifreezes.


Crystals of oxalic acid (

Propylene glycol undergoes the same kind of transformation in the liver as ethylene glycol, but has a different fate. It is metabolized to give pyruvic and lactic acids, which play a major part in biochemical reactions in all species of animals.

Pyruvic acid is a key component of the Krebs (citric acid) cycle, which is the primary source of cellular energy. The Krebs cycle converts fats, carbohydrates, and protein into adenosine triphosphate (ATP ) the fuel that makes life possible.

The dose makes the poison, according to the old saying, but sometimes so does one little carbon atom.

Stay warm.


Josh Bloom

Director of Chemical and Pharmaceutical Science

Dr. Josh Bloom, the Director of Chemical and Pharmaceutical Science, comes from the world of drug discovery, where he did research for more than 20 years. He holds a Ph.D. in chemistry.

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