The Chemistry of Alcohol in the Body

Alcohol is absorbed directly into the blood stream through the lining of the mouth and the tissue that lines the stomach and small intestine. Food, water, and fruit juice help to slow this absorption. Carbonated beverages speed the absorption of alcohol, which means that the drinker feels the effects sooner.

Once alcohol (or ethanol, the chemical in alcoholic beverages) is in your bloodstream, it is carried to the brain and all the organs of your body within 90 seconds. The affects of alcohol vary according to the individual’s sex, body size, amount of body fat, the amount of alcohol consumed, the situation, and the amount of food in the stomach.

Ten percent of the alcohol consumed is eliminated through sweat, breath, and urine. The liver begins working immediately to counteract the remaining toxic effects of alcohol. On average, the liver metabolizes, or breaks down, alcohol/ethanol at a rate of one half an ounce per hour (1/2 an ounce equals 14 grams.) A "standard" drink contains 12 grams of ethanol. That means the average person can metabolize about one standard drink per hour. However, some people’s livers metabolize alcohol more slowly.

When the amount of alcohol consumed exceeds the liver’s ability to break down the alcohol, the concentration of alcohol in the bloodstream (the proportion of alcohol to blood in the body) increases. Increased blood alcohol concentrations (higher proportions of alcohol to blood) impair thought processes and coordination, and slow automatic functions such as breathing. Excessive blood alcohol concentration can lead to coma or possibly death.

Nothing will speed the rate at which the liver is able to process alcohol. Only the passage of time -- at least one hour per drink consumed -- will make a drunk person sober.

The Chemistry of Alcohol in the Brain

Chemical messengers called neurotransmitters relay information in the brain. Each neurotransmitter binds to a particular receptor to create a response, although variations in the receptors can affect the response. A neuron’s response to information it receives depends on complex interactions of potentially conflicting messages that arrive simultaneously.

Alcohol is a depressant, which means it slows down the brain and body. It slows the function of the brain in two ways. First, it limits the actions of the neurotransmitter glutamate, which usually excites activity in the brain. Second, it elevates the activity of the inhibiting neurotransmitter gamma-aminobutyric acid (GABA).

Alcohol’s pleasurable effects and addictiveness are caused when alcohol:

• Increases the release of the neurotransmitter dopamine, which is related to pleasure, in an area of the brain that is associated with all types of addictions.
• Stimulates the activity of opioid peptides, which increases the pleasurable effects of alcohol.
• Activates serotonin receptors. This impacts serotonin’s many functions, including the regulation of mood, sleep, body temperature, and appetite and many others.
• Initiates neuroadaptation — changes caused by the brain attempting to function normally in the presence of alcohol.