Alcohol breaks down in the body in two stages: first it turns into the toxic compound acetaldehyde, and then the enzyme ALDH2 turns it into the harmless acetate, basically vinegar.
If the second stage of the process does not take place, harmful acetaldehyde accumulates in the body and causes unpleasant symptoms, including headaches.
In a study, scientists demonstrated in the laboratory that this happens when drinking red wine with a high content of quercetin: this substance can block the activity of the ALDH2 enzyme.
It needs to be tested with humans
The researchers suggest that quercetin only causes problems in the body when mixed with alcohol.
It is found in many fruits and vegetables and is even sold as a dietary supplement because of its beneficial anti-inflammatory properties.
Scientists have yet to test their theory on humans that it causes headaches after drinking red wine.
“We are finally on the right track to explain this thousands-year-old mystery. The next step is to scientifically test this theory in people who are prone to this type of headache, so stay tuned,” said study co-author Professor Maurice Levine, neuroscience expert and director of the UCLA Headache Center.
Consuming alcohol in large quantities and at high rates can have serious short-term and long-term health consequences.
The NHS warns that regular consumption of more than 14 units of alcohol per week (one unit is 10g of pure alcohol) can damage the liver and cause other health problems, including stroke and heart disease. That’s about six pint bottles of medium-strength beer or about ten small (125 ml) glasses of wine.
According to cancer research charity Cancer Research, alcohol causes seven different types of cancer. In the case of breast cancer – about one in ten diagnoses is related to alcohol consumption.