What Causes Alcohol Intoxication?
Alcohol is a generic term for ethanol, which is a particular type of alcohol produced by the fermentation of many foodstuffs - most commonly barley, hops, and grapes. Other types of alcohol commonly available such as methanol (common in glass cleaners), isopropyl alcohol (rubbing alcohol), and ethylene glycol (automobile antifreeze solution) are highly poisonous when swallowed, even in small quantities.
Ethanol produces intoxication because of its depressive effects on various areas of the brain causing the following physical and mental impairments in a progressive order as the persons alcohol level increases (the person becomes more and more intoxicated).
- Disinhibition of normal social functioning
- Euphoria (excessive talking, showing off)
- Ataxia (uncoordinated gait-walking)
- Poor judgment
- Loss of memory
- Slurred speech
- Worsening ataxia
- Confusion and disorientation
- Progressive lethargy and coma
- Ultimately the shutdown of the respiratory centers and death
What happens to brain function: Alcohol increases the effect of the body's naturally occurring neurotransmitter GABA (gamma amino butyric acid). Neurotransmitters are substances that chemically connect the signals from one nerve to the next allowing a signal to flow along a neural pathway. An inhibitory neurotransmitter (alcohol) reduces this signal flow in the brain. This explains how alcohol depresses both a person's mental and physical activities. By way of comparison, cocaine does the opposite by producing a general excitatory effect on the nervous system.
Available forms and measurement: A standard "drink" of ethanol consists of 10 grams. This amount is equal to:
- Ten ounces (300 cc) of regular beer (5% alcohol content);
- Three-and-a-quarter ounces of wine (12% alcohol content); or
- One ounce of hard liquor (40% alcohol content, 80 "proof").
Absorption: Approximately 20% of ethanol is absorbed into the bloodstream directly from the stomach, and 80% from the small intestine. Consequently, the longer the ethanol/alcohol remains in the stomach, the slower it will be absorbed and the lower the peak in the blood alcohol concentration (BAC).
- This explains the apparent sobering effect of food, which slows the process of emptying the stomach contents, slows the absorption of alcohol, and thus reduces the peak blood alcohol concentration reached.
- When alcohol is consumed with food, absorption generally is complete in 1-3 hours during which time the blood alcohol concentration will peak. If no further alcohol is consumed, sobering up will follow this peak level of blood alcohol concentration.
Distribution: Ethanol is highly soluble in water and is absorbed much less in fat. So alcohol tends to distribute itself mostly in tissues rich in water (muscle) instead of those rich in fat.
- Two people may weigh the same, yet their bodies may have different proportions of tissue containing water and fat. Think of a tall, thin person and a short, obese person who both weigh 150 pounds. The short, obese person will have more fat and less water making up his/her body than the tall, thin person. If both people, in this example, consume the same amount of alcohol, the short, obese person will end up with a higher blood alcohol concentration. This is because the alcohol he drank was spread into a smaller water "space."
- Women's bodies, on average, have more fat and less water than men's bodies. Using the same logic, this means that a woman will reach a higher blood alcohol concentration than a man of the same weight when both drink the same amount of alcohol.
Metabolism (elimination): Metabolism is the method by which the body processes alcohol and everything else a person eats or drinks. Some of the alcohol is converted to other substances (such as fat, as in "beer belly"). Some is burned as energy and converted to water and carbon dioxide. A small amount is excreted unchanged in the breath and urine. The liver metabolizes about 90% of the ethanol. The lungs excrete about 5% during exhalation (breathing out). Alcohol excretion by the lungs forms the basis for Breathalyzer testing. Another 5% is excreted into the urine.
- The average person metabolizes about one standard drink (10 grams) per hour.
- Heavy drinkers have more active livers ,and may be able to metabolize up to three drinks per hour.
- People with liver diseases will metabolize less than one drink per hour. In many chronic alcoholics, the liver becomes ineffective and can no longer metabolize alcohol, or anything else, efficiently. This is known as alcoholic cirrhosis.
- In alcoholic cirrhosis, the liver cells become badly scarred. This scarring has the effect of blocking blood flow through the liver, impeding exchange of metabolic chemicals into and out of the liver cells, and damaging the cells' ability to function.