Alcohol is by far the most powerful drug you can buy legally without a prescription. It is the most widely used mind-altering substance in the world, known to almost every culture since prehistoric times. It is also a narcotic.
Chemically, an alcohol is any of a class of organic compounds that have hydroxyl (OH) groups. Glycerol, mannitol, and sorbitol are alcohols mentioned elsewhere in this manual. Most people are familiar with rubbing alcohol, which is methyl alcohol. But the word alcohol by itself usually refers to ethyl alcohol, or ethanol, the ingredient in wine, beer, and distilled liquors.
From the moment alcohol enters the body, it gets special treatment. While most foods are digested slowly, the tiny alcohol molecule goes to the head of the line. About 20 percent of it enters the bloodstream directly from the walls of the stomach. It can reach the brain in less than a minute after ingestion. If the stomach contains food, there will be some delay before the alcohol enters the small intestine, but once there it will be absorbed quickly whether there is food present or not.
Liver cells are the only ones in the body that can metabolize alcohol at an appreciable rate. Only they produce enough of the enzyme alcohol dehydrogenase (NAD+) and its partner enzyme acetaldehyde dehydrogenase (NALD+), both from the B vitamin niacin. By dropping almost everything else it does, the liver can metabolize about one-half ounce of alcohol each hour. This is the about the amount of alcohol in four ounces of table wine, twelve ounces of beer, or one ounce of 100 proof liquor.
If you are fasting or on a very restrictive diet, there is much less NAD+ available, so the metabolism of alcohol may be reduced to half its normal speed. So drinking alcohol on an empty stomach gets alcohol into the bloodstream faster and it stays there longer.
Alcohol has a much simpler chemical structure than other mind-altering substances. Its chemical formula is C2H6O. Even sugars are complex by comparison. For example, the chemical formula for sucrose is C12H22O11. This has led some researchers to suggest that it is not the alcohol that produces addiction, but opiatelike by-products, which occur more often among alcoholics, and even among children of alcoholics.
One popular theory involves the neurotransmitter dopamine. The normal metabolism for dopamine requires the same NAD+ enzyme that is in short supply because of the metabolism of large amounts of alcohol. Instead of its normal metabolite, dopamine becomes a compound belonging to a class of chemicals called tetra- hydroisoquinolines (THIQ). These compounds are thought to behave a lot like opiates (Milkman & Sunderwirth, 1987, pp. 68-75).
These enzymes oxidize alcohol ﬁrst into acetaldehyde, and then into acetyl co-enzyme A (acetyl CoA), which would normally be used to produce energy. But that process has been suppressed, so the acetyl CoA is changed into fatty acids. After even one night of heavy drinking, these fatty acids can be detected building up in the liver. They also appear as elevated triglyceride levels in the blood.
There are three phases of liver damage: fatty liver, fibrosis, and cirrhosis. If the fat buildup in the liver lasts long enough, liver cells die, leaving ﬁbrous scar tissue. Abstinence from alcohol and good nutrition can reverse this damage in the fibrosis stage, but not after it has become cirrhosis.
Another mechanism that metabolizes some alcohol is called the MEOS (microsomal ethanol-oxidizing system). It handles about a ﬁfth of the alcohol a person drinks, but its function will expand if repeatedly exposed to alcohol. While it is not very signiﬁcant from an alcoholism perspective, it is important in relation to other drugs, because it metabolizes various other drugs as well as alcohol.
Suppose an alcoholic starts taking a sedative drug. The enlarged MEOS metabolizes the drug very rapidly, so the sedative wears off. The alcoholic takes a larger dose. This works ﬁne until one day the alcoholic takes the sedative after drinking heavily. The MEOS is now busy metabolizing alcohol, so the alcoholic overdoses on the sedative that, coupled with the depressant effects of the alcohol, can cause death.
Alcohol produces many other noxious effects in the body. The body’s acid-base balance (pH) shifts toward acid. The fatty liver has trouble making glucose from protein, resulting in ketosis. The liver slows down protein synthesis because it is busy with alcohol, so the immune system is less efﬁcient, weakening the body’s defense against infection. The stomach becomes inflamed, producing too much acid, and is likely to develop ulcers. Intestinal cells have trouble absorbing certain vitamins and minerals.
About 10 percent of the alcohol leaves the body through the breath and in the urine, making it possible to test the breath or urine for alcohol intoxication. Many alcoholics drink vodka in the mistaken belief that it cannot be detected on their breath.
Updated 1 Sep 2015
Addictionary 2 by Jan & Judy Wilson
is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.