An amount of alcohol equivalent to 1 to 2 bottles of beer is produced in the intestinal tract every 24 h so that the principal metabolising enzyme, alcohol dehydrogenase (ADH), is continually active. There are at least 21 isozymes of ADH in man and the significance of this multiplicity of isozymic species is just beginning to be explored. Other mammals have far fewer isozymes. for example, the rat has 2 and this calls into question the validity of rodents as models for the elucidation of human alcohol problems. An important physiological fact is that blood alcohol levels in humans are closely correlated with amount of intake in relation to body weight although other factors such as rapidity of drinking, rate of absorption from stomach and small intestine, and the medium in which the alcohol is contained, come to play. High alcohol intake induces an increased rate of glutathione turnover and decreased ability to metabolise toxic acetaldehyde. The assertion that alcoholic hepatitis and cirrhosis occur almost exclusively in persons who have an average daily intake exceeding 1.0 g/kg body weight has been shown by a number of studies to be untrue. One is cited in which hepatitis was found exclusively in a group consuming more than 200 g of alcohol per day. In another study cirrhosis was found exclusively among those drinking on the average at least a pint of spirits or its equivalent per day. There is some evidence that cirrhosis may be less common among primarily beer drinkers than among spirit drinkers. There is evidence also that moderate alcohol consumption may be beneficial to health. A decreased incidence of coronary heart disease, particularly myocardial infarction, is correlated with increased alcohol consumption. The same is true for coronary arteriosclerosis and is associated with enhanced levels of high density lipoprotein. The author sets the upper limit of moderate drinking at 0.7 g ethanol/kg body weight/day.
Keywords: alcohol brewing industry drinking habits physiology