Ah, a new year and a new headache. The revelry was a great deal of fun, but now your head feels like it’s been cloven in two and your tongue is stuck to the roof of your mouth. Add a little nausea and fatigue to the mix, and you’ve got a classic hangover.
While the immediate cause of a hangover—too much alcohol—is hardly earth-shattering, it’s interesting to dive deeper: how does alcohol, a really simple small molecule, cause all of this?
First, alcohol is metabolized in the liver, where two enzymes, alcohol dehydrogenase and aldehyde dehydrogenase, turn the alcohol molecule into water and CO2. But by then, the damage is done.
What else happens?
First, alcohol stimulates the activity of a neurotransmitter called GABA. This chemical inhibits a number of nervous system pathways, so the net result of active GABA is a state of relaxation. Alcohol also boosts activity of serotonin and endorphins, two other transmitters that help the body relax. This is why that first drink feels good, the second drink makes you loosen up, and the third, well….
Another big effect of alcohol is dehydration. Alcohol is a diuretic—it tells the pituitary gland to stop producing vasopressin, a hormone that aids kidneys to retain water. With less vasopressin, the kidneys keep churning water out of the body, and into the bladder. This explains your frequent trips to the toilet, and it also explains, once enough water has passed through you, your dehydration. Hence, the intense dry mouth feeling the morning after.
The diuretic effect of alcohol also depletes your body of vital minerals, such as sodium, potassium, calcium and magnesium. One study done a few years ago suggests that asparagus, which is full of these nutrients, might be a good way to alleviate hangover symptoms.
Alcohol also encourages blood vessels in your brain to expand (this could be part of GABA’s effects); this, in turn, causes headaches. It also irritates the lining of the stomach, prodding it to produce more stomach acid, which can lead to indigestion and nausea. Unfortunately, the long-term effects of doing too much of this can include permanent shrinking of brain cells and damage to your liver. Feeling better? Happy new year.