This woman woke up blind after her drink was tainted with methanol | The Current

[Nat Quinn]

 

 

So what is methanol, and how does it make people sick?

Methanol versus ethanol

Methanol is an alcohol, like the familiar ethanol we consume in alcoholic beverages.

Like ethanol, methanol is a colourless, flammable liquid. It has a smell similar to ethanol as well.

But the two have different chemical structures. Methanol is composed of only one carbon atom, while ethanol has two.

Methanol (left) and ethanol (right) have differing chemical structures. Wikimedia Commons, CC BY

That one carbon atom makes all the difference. It means methanol is processed differently in our bodies and is much more toxic than ethanol.

Methanol is used in a variety of industrial and household products, such as windshield cleaning fluids, antifreeze and fuel. It’s not safe for human consumption.

What makes methanol toxic?

The difference is in how methanol is metabolised, or broken down in our bodies.

Ethanol is metabolised into a chemical compound called acetaldehyde. Acetaldehyde is toxic, but is rapidly converted to acetate (also known as acetic acid, found in vinegar). Generating an acid may sound bad, but acetate actually produces energy and makes important molecules in the body.

By contrast, methanol is metabolised into formaldehyde (a chemical used in industrial glues and for embalming corpses, for example) and then to formic acid (the chemical in some ant bites that makes them hurt so much).

Unlike acetate, which the body uses, formic acid poisons the mitochondria, the powerhouses of the cells.

As a result, a person exposed to methanol can go into severe metabolic acidosis, which is when too much acid builds up in the body.

Methanol poisoning can cause nausea, vomiting, and abdominal pain. The acidosis then causes depression of the central nervous system which can cause people with methanol poisoning to fall unconscious and go into a coma, as well as retinal damage leading to vision loss. This is because the retinas are full of active mitochondria and sensitive to them being damaged.

Death is not inevitable if only a small amount of methanol has been consumed, and rapid treatment will greatly reduce damage.

However, permanent vision damage can occur even at non-lethal doses if treatment is not administered quickly.

[Author]

Posts