Your liver is a spongy, jack-of-all-trades organ that performs more than 1,500 chemical functions vital to life. Among those many functions this brown, three to four pound abdominal organic chemistry factory:
-- detoxifies poisons, both those produced by the body and those from outside,
-- filters bacteria from the blood,
-- regulates fat metabolism,
-- stores and manufactures vitamins.
-- regulates and manufactures cholesterol and fats,
-- synthesizes proteins,
-- maintains the body's water and salt balance,
-- secretes bile for the digestion of fat,
-- stores energy (in the form of glycogen),
-- helps regulate overall body metabolism,
-- transforms the highly toxic ammonia (produced by exercise and by metabolism of proteins) into urea which is eliminated in the urine,
-- manufactures lipoproteins for fat and cholesterol transport and
-- metabolizes alcohol.
Because of its vital functions, the liver receives about 25 percent of the heart's output, which forces the blood through the liver's billions of microscopic channels.
Cirrhosis is a condition in which the liver's active cells are replaced by fibrous scar tissue which lacks the ability to perform any of the hundreds of required chemical functions. When enough liver cells are replaced by scar tissue, you die.
The relationship between alcohol consumption and cirrhosis of the liver, a relatively rare condition, has been a problematic one for centuries. Prohibition-era activists, like modern-day anti-alcohol activists, exaggerated the threat to ordinary drinkers from cirrhosis, to scare them away from alcohol. But the fact is that most alcoholics will not get cirrhosis and many cirrhosis victims are people who have never drunk alcohol.
While alcohol abusers are more likely to suffer from cirrhosis than moderate drinkers (if you drink 14 drinks per day for 33 years, you have an 80 percent chance of getting it), the exact mechanisms of what causes it are still unclear. Indeed, there is no evidence that liver injury will occur in healthy men who consume fewer than four drinks per day and healthy women who daily consume fewer than three drinks.
While it is an important cause of illness and death, cirrhosis is not the major public health problem posed by coronary artery disease. In the United States (where annual per capita alcohol consumption is about 7.6 liters), the World Health Organization's 1989 World Health Statistics Annual found that the death rate from cirrhosis of the liver was 17 per 100,000 while cardiovascular disease killed 464 per 100,000. By contrast, the same study shows France (where per capita alcohol consumption is about 13 liters) with almost double the cirrhosis rate -- 31 per 100,000 -- but with cardiovascular rates at only 310 per 100,000.
On the face of it, this seems to show a direct, linear relationship between alcohol consumption and cirrhosis. But you can't make a decision based on just two points on a graph. Consider Japan whose per capita alcohol consumption is a bit lower than the United States at 6.3 liters and whose cirrhosis rate is 25 percent higher at 21 per 100,000 Ireland which also consumes about the same amount, 6.1 liters, has a cirrhosis rate less than one-fourth of the United States, 4 per 100,000.
Some alcohol-control advocacy groups assert that cirrhosis rates are artificially lower in some countries because the accuracy of diagnoses of the causes of death varies from country to country. No scientific evidence exists to prove such claims.
However, health statistics from numerous Western countries, including the U.S., indicate that only a fraction of the cirrhosis deaths can be attributed to alcohol consumption.
Dr. David Zakim, M.D., indicates that approximately half of cirrhosis deaths are associated with alcohol.
Taking this into account and using the WHO's death rate numbers, it is not hard to see that if the U.S. wine consumption and death rates were normalized with those of France, 7 more people per 100,000 (the half associated with alcohol) would die of cirrhosis, but 161 fewer people would die of cardiovascular disease. This is a net savings of 151 people who would live longer in order to die later of something else (for, after all, the death rate is eventually 100 percent).
In fact the statistics also hide a striking pattern in the French cirrhosis rates. Dr. Serge Renaud said that INSERM studied the rates on a regional basis and found the highest cirrhosis rates (50 to 100 per 100,000) in areas like those in the northern regions of Alsace and Lorraine which have the highest consumption of beer and spirits.
However, locales with the highest wine consumption, such as Provence, (which consume less beer and spirits), had the lowest cirrhosis rates -- 7 to 14 per 100,000 -- putting them even lower than the U.S.
"There are data, in fact, to suggest that ethanol [the main form of alcohol in beverages], per se, is not the cause of liver disease in abusers of alcohol," wrote Dr. David Zakim, M.D., author of "Pathophysiology of Liver Disease" published in the medical textbook, Pathophysiology: The Biological Principles of Disease. Dr. Zakim writes about two "well-controlled" studies which found that large doses of ethanol administered to hospitalized abusers as a way to ease the rigors of recovery, "did not impede clinical and laboratory recovery from decompensated alcohol-induced liver disease in patients eating a normal hospital diet."
Dr. Zakim, who is the Vincent Astor Distinguished Professor of Medicine at the Cornell University Medical College, Professor of Cell Biology at the Cornell University Graduate School of Medical Sciences and Director of the New York Hospital Division of Digestive Diseases, writes that, "Neither malnutrition nor ethanol ingestion causes serious liver disease, yet abuse of ethanol plus malnutrition produces liver disease in some patients. The cirrhogenic potential of ethanol is due to interactions with environmental factors, presumably with serious forms of liver disease requiring, in addition, a susceptible host [emphasis added] ... The best evidence available indicates that ethanol alone does not produce liver disease."
This uncertain relationship, however, should not be taken as a carte blanche to abuse alcohol since abuse does put you in a higher risk category.
The liver is the focus of medical research into the effects, both beneficial and harmful, of alcohol. The liver metabolizes alcohol and is the focus of cholesterol and fat synthesis, transport and regulation.
Alcohol in wine, beer and spirits is absorbed through the membranes of the mouth and the esophagus, but mostly from the stomach and intestines. The speed with which it is absorbed varies with the type of alcoholic beverage: the higher the alcohol concentration, the faster it is absorbed. Straight spirits are absorbed faster than wine and beer. However, research indicates that when spirits are diluted and alcohol is added to beer to bring them to the same concentration as wine (about 12 percent), the alcohol in wine is absorbed more slowly than with either of the other two.
The rate of absorption is also affected by the ingestion of food. Once absorbed, about 10 percent of the alcohol is eliminated through perspiration and through breathing. The other 90 percent is metabolized by an enzyme, alcohol dehydrogenase, with the help of other substances from digested food. Most of this enzyme resides in the liver. However, the lining of the stomach also contains alcohol dehydrogenase, which affects the rate at which alcohol is absorbed from the stomach. Some research indicates that men have more of this enzyme than women; the result is that women will have a higher blood alcohol level than men, even when body size is taken into consideration.
Alcohol dehydrogenase is saturated when the blood alcohol level reaches 46 mg/dl (equivalent to 0.046); this amounts to about 10 grams of alcohol per hour in a 155-pound man. A woman of the same size would reach the saturation point at about two-thirds of this consumption level.
Although alcoholics metabolize alcohol faster than moderate drinkers, their livers do not produce more alcohol dehydrogenase. Research indicates that other parts of the metabolism cycle are speeded up.
However, alcohol does not accumulate in the blood of a non-alcoholic, healthy, well-fed person so long as consumption levels are below 8 to 10 grams per hour. Because alcohol dehydrogenase needs the help of substances from the digestion of food, people who have not eaten absorb alcohol faster and metabolize it more slowly. Wine is a healthier beverage because it is usually consumed with meals and because the alcohol in wine is absorbed more slowly than the alcohol in other beverages.
Harmful effects of alcohol are dose-related as are the cardio-protective effects of moderate consumption. Although it is a hypothesis at this point in medical research, many scientists feel that peak blood alcohol levels may be a major factor in determining the level where consumption crosses the line from good to bad. Some feel that the 46 mg/dl (.046 BAC) may be that line.
Certainly this is a good point to stay below. It seems to be the liver's saturation point and it's about half of the 0.08 to 0.10 maximums that most states use to determine legal intoxication for drivers.