Alcohol primarily works by rapidly entering your bloodstream and affecting your central nervous system, altering brain function, and subsequently impacting various organs throughout your body. Unlike food, alcohol isn't digested in the traditional sense; instead, it passes quickly into your bloodstream and travels to every part of your body.
The Journey of Alcohol Through Your Body
When you consume an alcoholic beverage, its journey and effects unfold in several key stages:
1. Absorption
As soon as you drink alcohol, a small amount is absorbed directly through the mucous membranes in your mouth and throat. However, the majority of absorption occurs in the digestive tract:
- Stomach: Approximately 20% of alcohol is absorbed through the stomach lining. This process can be slowed by food, which is why drinking on an empty stomach leads to faster effects.
- Small Intestine: The remaining 80% quickly moves into the small intestine, where it's rapidly absorbed into the bloodstream.
2. Distribution
Once absorbed, alcohol doesn't stay in one place. It travels to every part of your body because it's water-soluble and easily crosses cell membranes. The speed and intensity of its effects are influenced by several factors:
- Body Water Content: Individuals with a higher percentage of body water (typically men) tend to have a lower blood alcohol concentration (BAC) for the same amount of alcohol consumed compared to those with less body water (typically women).
- Weight: Heavier individuals usually have a larger volume of blood and body water, which dilutes the alcohol more, leading to a lower BAC.
- Gender: Women generally metabolize alcohol slower than men due to lower levels of the enzyme alcohol dehydrogenase (ADH) in the stomach, and typically have less body water.
- Age: As people age, their body water content tends to decrease, which can lead to higher BACs.
- Type of Alcohol: Carbonated beverages can speed up alcohol absorption, as can drinks with higher alcohol concentrations.
- Rate of Consumption: Drinking quickly leads to a faster rise in BAC.
3. Impact on the Brain
Alcohol affects your brain first because it can easily cross the blood-brain barrier. It acts as a central nervous system depressant, meaning it slows down brain activity. This occurs primarily by interfering with neurotransmitters, the chemical messengers in the brain:
- Enhancing GABA: Alcohol increases the effects of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter. This leads to feelings of relaxation, drowsiness, and reduced anxiety, but also impaired coordination and judgment.
- Inhibiting Glutamate: It suppresses the activity of glutamate, an excitatory neurotransmitter responsible for learning and memory. This can lead to memory blackouts and difficulty processing new information.
- Dopamine Release: Alcohol also triggers the release of dopamine, a neurotransmitter associated with pleasure and reward, contributing to its addictive potential.
4. Metabolism and Elimination
The body processes alcohol mainly in the liver, with small amounts eliminated through the breath, urine, and sweat.
- Liver Processing: The liver metabolizes about 90% of the alcohol consumed. Enzymes like alcohol dehydrogenase (ADH) break down alcohol (ethanol) into acetaldehyde, a toxic compound. Acetaldehyde is then further broken down by aldehyde dehydrogenase (ALDH) into acetate, a harmless substance that is eventually converted into water and carbon dioxide.
- Fixed Rate: The liver metabolizes alcohol at a relatively fixed rate, typically about one standard drink per hour. This rate cannot be sped up by drinking coffee or taking a cold shower.
- Other Organs: After the brain, alcohol continues to circulate, affecting your kidneys, lungs and liver significantly over time. The kidneys work to excrete excess fluid and toxins, increasing urine production. The lungs exhale small amounts of alcohol, which is why breathalyzers work.
Effects of Alcohol on the Body
The effects of alcohol can be categorized into short-term (acute) and long-term (chronic) impacts.
Short-Term Effects (Acute)
These effects are directly related to the rising Blood Alcohol Concentration (BAC):
| BAC Level (%) | Effects |
|---|---|
| 0.02-0.03 | Mild relaxation, slightly altered mood, warmth. |
| 0.05-0.06 | Impaired judgment, reduced inhibitions, impaired coordination. |
| 0.08 | Legal intoxication limit in many places; significant motor impairment, slurred speech. |
| 0.10-0.12 | Clear deterioration of coordination and judgment, slowed reaction time. |
| 0.15-0.20 | Nausea, vomiting, significant loss of balance and motor control. |
| 0.25-0.30 | Severe mental and physical impairment, risk of aspiration. |
| 0.35+ | Coma, respiratory depression, potential for fatal alcohol poisoning. |
Learn more about the acute effects of alcohol from the National Institute on Alcohol Abuse and Alcoholism (NIAAA).
Long-Term Effects (Chronic)
Chronic heavy alcohol consumption can lead to serious health issues impacting nearly every organ system:
- Liver Damage: Fatty liver, alcoholic hepatitis, cirrhosis.
- Brain Damage: Shrinkage of brain tissue, cognitive impairments, memory problems, increased risk of dementia.
- Cardiovascular System: High blood pressure, irregular heartbeat, weakened heart muscle (cardiomyopathy), increased risk of stroke.
- Digestive System: Gastritis, pancreatitis, ulcers, increased risk of various cancers (mouth, throat, esophagus, liver, colon).
- Immune System: Weakened immune response, making the body more susceptible to infections.
- Mental Health: Worsening anxiety, depression, and other mental health conditions.
- Dependency: Development of alcohol use disorder, characterized by a compulsive need for alcohol.
Understanding how alcohol works in the body emphasizes the importance of responsible consumption and awareness of its potential impacts on health and well-being.
