Wine’s intoxicating effects stem from a single chemical compound. Understanding its journey through the body and impact on the brain reveals the biological mechanisms behind feeling drunk.
Ethanol: Wine’s Active Compound
Ethanol, also known as ethyl alcohol, is the primary intoxicating agent in wine and all alcoholic beverages. It is a natural byproduct of fermentation, integral to winemaking. During fermentation, yeast consumes the sugars present in grape juice, converting them into ethanol and carbon dioxide.
The alcohol content of wine, often expressed as Alcohol by Volume (ABV), can vary, typically ranging from 7% to 15%. A higher ABV signifies a greater concentration of ethanol, which directly correlates with the wine’s intoxicating potential. This transformation gives wine its intoxicating potential.
From Glass to Bloodstream: Absorption and Processing
After consumption, ethanol begins its journey through the digestive system. A small amount, approximately 10% to 20%, is absorbed directly into the bloodstream through the lining of the stomach. However, the majority of ethanol, about 75% to 80%, passes into the small intestine, where its absorption into the bloodstream occurs much more rapidly due to the intestine’s large surface area and rich blood supply.
The bloodstream carries ethanol throughout the body to organs and tissues, including the brain. The liver plays a primary role in metabolizing ethanol, breaking it down into less harmful substances. This process involves two enzymes: alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). ADH first converts ethanol into acetaldehyde, a toxic compound, which ALDH then quickly transforms into acetate, a less toxic substance that is further broken down and eliminated from the body.
How Alcohol Affects the Brain
After absorption, ethanol crosses the blood-brain barrier, accessing the central nervous system. In the brain, it interferes with neurotransmitters, chemical messengers that transmit signals between nerve cells. Specifically, ethanol enhances the effects of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter responsible for reducing brain activity. This enhancement leads to feelings of relaxation, sedation, and a reduction in inhibitions, contributing to the typical effects of intoxication.
Ethanol also suppresses the activity of glutamate, an excitatory neurotransmitter. By inhibiting glutamate, alcohol slows down brain functions, resulting in impaired judgment, slurred speech, and slowed reaction times. Additionally, alcohol consumption can increase dopamine levels in the brain’s reward centers, contributing to the pleasurable sensations some individuals experience, which can reinforce drinking behavior.
Why People Get Drunk Differently
Several factors influence how quickly and intensely an individual experiences the effects of wine. Body weight and composition play a role, as alcohol distributes throughout the body’s water content; individuals with less body water will have a higher concentration of alcohol in their bloodstream for a given amount consumed. Gender differences also exist, with women generally having less body water and lower levels of gastric alcohol dehydrogenase (an enzyme that breaks down alcohol in the stomach) compared to men, often leading to higher blood alcohol concentrations from the same amount of wine.
Food consumption before or during drinking can slow the absorption of alcohol into the bloodstream, as it can delay the emptying of the stomach into the small intestine. The rate at which wine is consumed also affects intoxication levels; drinking quickly leads to a faster rise in blood alcohol concentration. Individual metabolic variations, particularly genetic differences in the efficiency of ADH and ALDH enzymes, can further influence how rapidly alcohol is processed and how long its effects last.