DIET COMPOSITION, ALCOHOL UTILIZATION, AND DEPENDENCE

Experiments were carried out in which a nutritionally balanced liquid diet previously used in this laboratory was modified as to total calor ie content and high or low carbohydrate and fat concentration. Ethanol was added at 4.5% and 6.2% of diet weight and provided either 27% or 34-37% of total calories depending upon the changes in nutrient conten t. Measurements included 8-day food/calorie and ethanol consumption, p lasma ethanol level, liver alcohol dehydrogenase (ADH) activity, and r ate of audiogenic-induced withdrawal seizures. The original liquid die t with 4.5% ethanol was consumed in significantly lesser amounts than the alcohol-free diet, and essentially no body weight gain occurred, r egardless if the major nonalcohol, nonprotein calorie source was fat o r carbohydrate. When the calorie content of the diet was boosted throu gh the addition of extra carbohydrate or fat (at the expense of water) , appreciable weight gain was noted; in the case of the higher calorie diet boosted with more carbohydrate (maltodextrin) calories, growth w as similar to that observed on the alcohol-free control diet. On this latter diet ethanol calories appeared to be utilized close to their th eoretical value of 7 kcal/g. Blood alcohol levels were significantly h igher on the lower calorie diets and were lowest on the high-calorie, high-carbohydrate, 4.5% ethanol diet. This diet also allowed for the l owest rate of withdrawal seizures despite an ethanol intake that was a s high as on the lower calorie diets. Essentially, no differences were noted among ADH activities for the dietary treatments studied and thu s, did not explain the differences observed among blood ethanol levels . When the alcohol concentration in the high-carbohydrate, high-calori e diet was raised to 6.2% from 4.5% to provide 34% of total calories, the rats responded by decreasing their food (and alcohol) intake to th e same level as did the animals receiving a much lower calorie diet, b ut with 37% of caloric alcohol content. This suggests that at a diet a lcohol concentration of 34-37%, one or more nutrient metabolites becom e limiting in the utilization of ethanol, resulting in food intake adj ustments that maintain similar amounts of alcohol consumption.