Ethanol

Abstract

Ethanol is readily water-soluble, and has a limited capacity to dissolve slightly hydrophobic molecules. It is an energy-rich nutrient that provides about 7 kcal/g and its conversion to acetyl-CoA requires riboflavin, niacin, pantothenate, zinc, (heme) iron, molybdenum, and magnesium; further oxidation of acetyl-CoA to water and carbondioxide depends on thiamin, riboflavin, niacin, pantothenate, lipoate, ubiquinone, iron, and magnesium. The ethanol metabolite acetate can be used as a precursor for fatty acid and cholesterol synthesis. Alcoholic beverages typically contain 10-20 g ethanol per serving. Foods do not contain significant amounts of alcohol unless they are steeped in liquor. Ethanol is converted completely into acetyl-CoA, which is little compared to the several hundred grams that are generated daily during the breakdown of carbohydrates, fat, and protein. Even moderate intakes of ethanol slow response time, impair motor control, limit judgment, and thus increase the risk of accidents and perpetrating or suffering crimes. Acute poisoning with large amounts can induce coma and death. Chronic abuse can lead to dependency, increase cancer risk, induce bone loss, and cause damage to liver, heart, pancreas, brain, and other organs. Ethanol is absorbed in the stomach and proximal small intestine. Since ethanol readily permeates lipid membranes the main transfer mechanism appears to be diffusion. The lining of mouth, esophagus. and stomach has significant capacity for the first steps of ethanol metabolism. Because of this, a small proportion of ingested ethanol is transferred into blood as acetaldehyde and acetic acid. Ethanol consumption increases intestinal motility and may cause diarrhea. Ingestion of significant amounts may interfere with the intestinal absorption of amino acids, folate, and other nutrients.