Methanol is a toxic substance commonly found in illicit alcohol, differing from ethanol only in the number of carbon and hydrogen atoms but can be lethal in small doses.
Methanol is a synthetic alcohol commonly used in coolants and windshield washer fluids, according to Live Science. Similar to ethanol, this type of alcohol is often present in beverages, but methanol is toxic to the body. At the molecular level, it differs from ethanol by containing one less carbon atom and two less hydrogen atoms, leading to different processing by the kidneys for the two types of alcohol.
The main component of regular drinking alcohol is ethanol, with the chemical formula C2H5OH, while methanol has the chemical formula CH3OH. Both types of alcohol are produced through fermentation and distillation.
Methanol in illicit alcohol is highly toxic. (Illustrative image: Live Science).
According to the U.S. National Institutes of Health (NIH), the metabolism of ethanol in the liver begins when an enzyme called alcohol dehydrogenase converts this chemical into another toxic substance called acetaldehyde. Acetaldehyde is quickly metabolized and will be transformed into non-toxic CO2 and water in just a few steps.
However, the metabolism of methanol is not as smooth. This chemical depresses the central nervous system similarly to ethanol. Therefore, if consumed in large amounts, methanol can be lethal, similar to cases of regular alcohol poisoning.
Unlike ethanol (the type of alcohol commonly found in alcoholic beverages), when methanol is ingested, the human body produces formaldehyde, formic acid, and formate, all of which are harmful substances.
Among these, formate is the primary toxin produced, acting similarly to cyanide and inhibiting energy production in cells, with the brain appearing particularly vulnerable to this substance.
Methanol poisoning affects various parts of the body, causing a range of symptoms such as vomiting, headaches, visual disturbances (which may include partial or complete loss of vision), and difficulty breathing. In severe cases, methanol poisoning can lead to seizures, coma, and death.
According to Dr. Wayne Carter, an associate professor at the University of Nottingham’s Medical School (UK), the lethal dose of methanol varies from person to person, potentially as low as 15ml of a solution containing 40% methanol.
Dr. Nguyen Trung Nguyen, Director of the Poison Control Center at Bach Mai Hospital, stated that ethanol is metabolized very quickly in the body, whereas methanol is the opposite, with its metabolism and elimination occurring very slowly (it can still be present in the blood after 7-8 days).
The process unfolds very slowly, leading to methanol poisoning symptoms sometimes appearing only after several hours or days. Once signs of poisoning manifest, chemical reactions occur rapidly, producing the final product, formic acid, a chemical that is slowly metabolized and found in ant bites.
The accumulation of formic acid damages the optic nerve, which can lead to permanent blindness and even death if not detected in time.
Chemical formulas of methanol and ethanol. (Image: WordPress).
Due to its toxicity, methanol is sometimes added to ethanol-containing products used in industry as a solvent to eliminate the possibility of their use as beverages. By adding methanol, manufacturers can avoid taxes applied to alcoholic beverages and sell products at a lower production cost.
Some irresponsible and illegal businesses often add methanol to alcoholic drinks because this product is cheaper than producing ethanol. Additionally, high levels of unwanted methanol can inadvertently be produced during the fermentation of beverages with high pectin content, such as those made from grapes and strawberries. Under proper clean fermentation conditions, methanol is produced at low and safe levels. However, bacteria can cause methanol to be produced at higher levels in unsanitary containers.
There are many forms of methanol poisoning, such as consuming counterfeit alcohol or disinfectant alcohol. Most cases that arrive at the hospital are severe, involving coma, metabolic acidosis, and some individuals suffer from eye and brain damage, resulting in unilateral blindness, and there have even been recorded fatalities.
Experts suggest that authorities need to strictly regulate industrial methanol to prevent the production of counterfeit alcohol by mixing methanol, which can lead to poisoning and pose serious, long-term health risks to consumers.
