Transient and isolated over-indulgence may irritate the liver, but, with its enormous regenerative capacity,it quickly heals. Repetitive major insults over the years, however, are likely to lead to lasting damage, in sequential order of gravity: inflammation (alcoholic hepatitis), fatty liver (hepatic steatosis), and, finally, cirrhosis. In each case, structural abnormalities are accompanied by disorder of the vital almost unimaginable complex of liver functions. While the degree of damage is in general proportional to the quantity of alcohol imbibed, there are wide individual differences in susceptibility.

Alcoholic cirrhosis is a common cause of disability and death among heavy drinkers. It accounts for much of the steeply increasing death rate of the right side of the J-shaped curve. (The curve illustrates that light to moderate drinkers live longer and healthier than abstainers, and do very much better than those who drink to excess.) Those with cirrhosis of the liver of any cause are also at higher risk of development of hepatoma (liver cancer), nearly always fatal.

In addition to causing liver damage by excess, alcohol, at least when abused, inhibits liver regeneration (healing) from any damage, by viral hepatitis, toxin, medication overdose (acetaminophen), hemochromatosis (hereditary iron overload), or alcohol itself.

Let us turn to the surprising study of Manna Zhang, et al., published in the November, 2000, issue of the journal Gastroenterology. Working in the laboratory of Gerald Minuk at the University of Manitoba Liver Diseases Unit in Winnipeg, Canada. They fed laboratory rats light, moderate, or heavy portions of alcohol, or tap water, for 30 days before removal of a substantial proportion of the rats livers. The regeneration of the liver was then measured by sophisticated techniques. The rats engaging in heavy consumption of alcohol clearly showed impairment of regeneration. The moderate consumers were negligibly impacted, perhaps a trace tilt toward impairment. The light-drinking rats, however, exhibited enhanced regeneration, that is, they did considerably better than those who drank only water.

The mechanisms of improved liver regeneration among the light-drinking rats are not known. Two proposed are favorable effects upon cell membranes and inhibition of inhibitors of regeneration. It must be borne in mind that this is just one experiment, and that it is in rats, not humans, so, before assigning these results as still another illustration of the increasingly universal J-shaped curve, conventional prudence would dictate abstinence for those of us with active liver disease.

Can the body generate alcohol?

I once saw a film about a non-drinking man who got into trouble with the law because of alcoholic intoxication. He got out of trouble when it was demonstrated that the alcohol had been manufactured in his gastro-intestinal tract. An amusing fantasy, I thought.

Now, in the same issue of Gastroenterology, Cope, Risby, and Diehl, at John Hopkins University, Baltimore, propose that the fatty livers occurring in obese individuals may be caused by alcohol generated within the intestine.

This time its mice, obese versus lean mice, that were studied. The mice were abstinent of alcohol, yet ethyl alcohol, our favourite kind, was detectable in the exhaled breaths of the mice. Obese mice had more than thrice the alcohol of lean mice. The peak concentration occurred in the morning. Breath alcohol of the obese mice increased with age; not so in lean mice. The antibiotic, neomycin, administered orally, reduced alcohol levels by 50 percent.

It is thought that micro-organisms normally living in the intestine produce the alcohol, which flows via the blood stream to the liver, its next station. Obesity is thought to slow intestinal motility, thereby enabling bacterial over growth, with resultant increased production of alcohol and other noxious factors. The occurrence of abnormal (fatty) livers in obese mice is quite similar to that seen in obese humans. It sometimes leads to even more serious liver damage. Are safe limits of alcohol consumption lower for obese people? We dont know yet.

Certainly further studies are needed, but one may wonder about corrective measures, such as weight reduction, prudent use of antibiotics, and enlistment of beneficial competing microorganisms, e.g., lactobacillus.

*Dr. Finkel, clinical professor of medicine at Boston University Medical Center, founding chairman of the Committee on Health of the Society of Wine Educators, and award-winning wine writer, writes and lec-tures internationally on the influences of wine upon health. He is a member of AIMs editorial board.