The Athlete

Drug Abuse

ABSORPTION, DISTRIBUTION, & METABOLISM

ABSORPTION & DISTRIBUTION
When someone drinks an alcoholic beverage, it is slightly diluted by digestive juices in the mouth and stomach. Because alcohol is readily soluble in water and doesn't need to be digested, it immediately begins to be absorbed and distributed. Absorption of alcohol into the bloodstream takes place at various sites along the gastrointestinal tract, including the stomach, the small intestines, and the colon. It enters the capillaries through passive diffusion.

Though most drugs must be passed into the intestine for absorption, alcohol is one of the few that is partially absorbed through the stomach. In men about 20% of the alcohol is absorbed by the stomach wall while in women there is almost no absorption by the stomach. Given the same body weight, women and men differ in their processing of alcohol. Women have higher blood alcohol concentrations than men do from the same amount of alcohol. A woman who weighs the same as a man and drinks the same number of drinks as a man absorbs about 30% more alcohol and feels its psychoactive effects faster and more intensely (NIAAA, 1990).

This difference between women's and men's reaction to alcohol results from three possible explanations.

- Women have a lower percentage of body water than men of comparable size, so there is less water to dilute the alcohol in women resulting in higher alcohol concentrations in the blood.
- Women have less active alcohol dehydrogenase enzyme in the stomach to break down alcohol, so less alcohol is metabolized before getting into the blood, also resulting in higher concentrations.
- Finally, changes in gonadal hormone levels during menstruation affect the rate of alcohol metabolism, again resulting in higher blood concentrations at different points in the cycle (NIAAA, 1990).

The caption of the sketch by Henri Daumier says, "My wife, you are wrong to blame me... as a famous philosopher has said,'It's only drinking wine when you're not thirsty that distinguishes man from the rest of the animals.'"

Thus chronic alcohol use causes greater physical damage to women than to men-female alcoholics have death rates 50% to 100% higher than male alcoholics (NIAAA, 1990).

The alcohol that isn't absorbed in the stomach passes into the small intestines where it is absorbed into the bloodstream and partially metabolized by the liver and then quickly distributed throughout the body. Since alcohol molecules are small, water-soluble, lipid-soluble, and move easily through capillary walls by passive diffusion, they can enter any organ or tissue and in the case of pregnancy, can even cross the placental barrier into the fetal circulatory system (O'Brien, 1991). Once alcohol reaches the brain and passes through the blood-brain barrier, psychoactive effects gradually begin to occur. The highest levels of blood alcohol concentration occur 30-90 minutes after alcohol is drunk. How quickly the effects are felt is determined by the rate of absorption. Absorption is influenced by an individual's weight, body chemistry, and factors such as emotional state (e.g., fear, stress, fatigue, or anger), state of health, body fat, food taken with the alcohol, and even the outside temperature. Women absorb more alcohol during the premenstrual period than at other times.

Distillatio by Philip Galle. Distillation in this sixteenth centry Dutch laboratory supplies alcohol for making medicines and for drinking. In distillation, a liquid is boiled and the vapors are drawn off, cooled, and condensed into a liquid. A clear, colorless, almost 100% pure grain alcohol distillate can be created using this process. Courtesy of the National Library of Medicine, Bethseda

Other factors that speed absorption and cause a faster high in both men and women are:- increasing either the amount drunk or the drinking rate;
- drinking on an empty stomach;
- using high alcohol concentrations in drinks, up to a maximum of 40-50%;
- drinking carbonated drinks, such as champagne, sparkling wines, soft drinks, and tonic mixers;
- warming the alcohol (e.g., hot toddies, hot saké).

Factors that slow absorption and cause a slower high are

- eating before or while drinking (especially meat, milk, cheese, and fatty foods);
- diluting drinks with ice, water, or fruit juice that lower the amount of alcohol available for absorption.
(Jones & Pounder, 1998; Longenecker, 1994).

Table 5-2. Approximate percentage of alcohol in certain beverages (by volume)
Wine
Unfortified, natural: red, white, rosé
12 - 14%
Fortified, dessert: sherry, port, muscatel
17 - 21%
Champagne
12%
Vermouth
18%
Wine cooler
6%
Beer
Regular beer
4 - 5%
Light beer
3 - 7%
Malt liquor
6 - 9%
Ale
5 - 6%
Ice beer
5 - 7%
Low-alcohol beer
1.5%
Nonalcoholic beers (Odoul's®, Sharpe's®)
0.5%
Liquors and Whiskeys
Bourbon, whiskey, scotch, vodka, gin, brandy, rum
40 - 50%
Tequila, cognac, Drambui®
40%
Amaretto®, Kahlua®
26%
Everclear®
95%
(Note: To calculate the proof of a product, double the alcohol content: e.g., 40% alcohol = 80 proof, 100% alcohol = 200 proof.)

METABOLISM
Because the body treats alcohol as a toxin or poison, elimination begins as soon as it is ingested. Approximately 2% to 10% of the alcohol is eliminated directly without being metabolized; a small amount is exhaled via the lungs while additional amounts are excreted through sweat, saliva, and urine. The remaining 90% to 98% of alcohol is neutralized through metabolism (mainly oxidation) by the liver and then by excretion through the kidneys and lungs (Jones, 1998).
Alcohol is metabolized in the liver, first by alcohol dehydrogenase (ADH) into acetaldehyde, which is very toxic to the body and especially the liver, and then by acetaldehyde dehydrogenase (ALDH) into acetic acid that is finally oxidized into carbon dioxide (CO2) and water (H2O) (Fig. 5-2). The varying availability and efficiency of ADH and ALDH, due in part to hereditary capabilities, accounts for some of the variation in people's reaction to alcohol (Bosron, Ehrig, & Li, 1993).

- As mentioned earlier, women have less ADH in the stomach than men, so they are less able to metabolize alcohol, thus they will have a higher BAC than men for an equal amount of ingested alcohol (NIAAA, 1990).
- About half of all Japanese, along with some other Asian populations (e.g., Chinese), are born with a more efficient ADH called "atypical ADH" and a less efficient form of ALDH known as "KM ALDH1," thus when they drink even small amounts of alcohol, the toxic acetaldehyde builds up (up to 10 times the normal amount) and causes a flushing reaction due to vasodilation. Tachycardia and headaches also occur. At higher doses, edema (water retention), hypotension, and vomiting occur (Goedde, Harada, & Agarwal, 1979, 1983; Teng, 1981; Woodward, 1998). Though Asians have a higher rate of abstention and lower rate of alcoholism, Asian-Americans' rate of alcoholism is higher, showing that environmental and cultural influences can overcome biological propensities (Lee, 1987).

Figure 5-2. Metabolsim is accomplished in several stages involving oxidation. First the enzyme alcohol dehydrogenase (ADH), found in the stomach and the liver, acts on the ethyl alcohol (C2H5OH) to form acetaldehyde (CH3CHO), a highly toxic substance. Acetaldehyde is then quickly acted on by a second enzyme, acetaldehyde dehydrogenase (ALDH), that oxidizes it into acetic acid (CH3COOH). Acetic acid is then further oxidized to carbon dioxide (CO2) and water (H2O).

- Although there is no confirming research, it is suspected that the high rate of alcoholism and the high rate of cirrhosis of the liver in Native Americans is due to disruptions in the ALDH and ADH systems as well as a tradition of binge drinking patterns.
- Some speculate that if a person has the wrong ALDH, then the normal benefits of light to moderate drinking are not present, therefore the main benefit sought in drinking is getting high-not relaxing, not whetting one's appetite, not becoming more social-only getting high, which takes large amounts of alcohol. The health risks of such a binge pattern are much greater.

Besides ALDH irregularities, drugs such as aspirin also inhibit metabolism of alcohol and lead to higher blood alcohol concentration in both men and women.
In many countries, alcoholic beverages are used primarily as a source of nutrition while in others they are used primarily for their mind-altering effects. Alcohol is a very concentrated energy source, almost as much as pure fat but they are empty calories, i.e., high caloric content with no real food value. On average, alcoholics get half their energy intake from alcohol and, as a result, are much more susceptible to malnutrition, particularly thiamine, folate, and other vitamin B deficiencies. This is in addition to digestive upsets and pancreatic problems. Disruption of liver function also leads to disrupted digestive patterns (Lieber, 1998).

"We get drunk and we have fun. We have a good time. That's what we're about. And I'm healthy. I'm in better shape than any of you guys . . . well maybe not on the inside. My stomach's kind of messed up a little bit. I can't drink liquor that good. I did take blood tests. I get my results on Friday . . . I forgot."
25-year-old male alcohol abuser

Blood Alcohol Concentration (BAC)
Though absorption of alcohol is quite variable, metabolism occurs at a defined continuous rate. About one ounce of pure alcohol is eliminated from the body every 3 hours. Thus we can usually predict the amount of alcohol that will be circulating through the body and brain and how long it will take that amount to be metabolized by the liver and eliminated via urination, sweating, and breathing. However, each person's actual reaction and level of impairment can vary widely, depending on drinking history, behavioral tolerance, and a dozen other factors. It takes about 15-20 minutes for alcohol to reach the brain via the blood and cause impairment but more time for it to enter the urine. It takes 30-40 minutes after ingestion to reach maximum blood alcohol concentration (NIAAA, 1997).

This blood alcohol concentration table (Table 5-3) measures the concentration of alcohol in a drinker's blood. In most states, legal intoxication is .08 or .10. Some think it should be .05 for safety. In general alcohol is metabolized at the rate of 1/4 oz. to 1/3 oz. per hour. The unit of measurement for BAC is weight by volume, e.g., milligrams per deciliter, but can be expressed as a percentage, e.g., .10% alcohol by volume (Bailey, 1995).For example, if a 200 lb. male has five drinks in two hours, his blood alcohol would be .108 minus the timetable factor of .030, so his BAC would be about .078 and he would be legally sober enough to drive in many states. If his 200 lb. female companion has five drinks in two hours, her blood alcohol level would be .126 minus the timetable factor of .030, so her BAC would be .096 and not only would she be quite a bit more intoxicated than her companion even though they weighed the same and drank the same amount over the same period of time but she would also be legally drunk in many states.

Table 5-3. Approximate blood alcohol concentration for different body weights
No. of Drinks
1
2
3
4
5
6
7
8
9
10
Male
100 lbs.
.043
0.87
.130
.174
.217
.261
.304
.348
.391
.435
125 lbs.
.034
.069
.103
.139
.173
.209
.242
.287
.312
.346
150 lbs.
.029
.058
.087
.116
.145
.174
.203
.232
.261
.290
175 lbs.
.025
.050
.075
.100
.125
.150
.175
.200
.225
.250
200 lbs.
.022
.043
.065
.087
.108
.130
.152
.174
.195
.217
225 lbs.
.019
.039
.058
.078
.097
.117
.136
.156
.175
.195
250 lbs.
.017
.035
.052
.070
.087
.105
.122
.139
.156
.173
Female                    
100 lbs.
.050
.101
.152
.203
.253
.304
.355
.406
.456
.507
125 lbs.
.040
.080
.120
.162
.202
.244
.282
.324
.364
.404
150 lbs.
.034
.068
.101
.135
.169
.203
.237
.271
.304
.338
175 lbs.
.029
.058
.087
.117
.146
.175
.204
.233
.262
.292
200 lbs.
.026
.050
.076
.101
.126
.152
.177
.203
.227
.253
If a person drinks over a period of time, the alcohol is metabolized at a rate of .015 per hour. Use the following table to factor in the time since the first drink.
Timetable Factors
Hours since first drink
1
2
3
4
5
Subtract from BAC
.015
.030
.045
.060
.075

Information on Drug Abuse:

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Information on Alcohol:

Alcohol Home

History

Overview

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Epidemiology of Alcohol Consumption

Absorption, Distribution and Metabolism

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