Nutrition is the process that provides energy for the body and helps it maintain structure and function (Alcohol, 2000). Once food is ingested, it is broken down into small components and digestion begins in the mouth and continues in the stomach and intestines. The digested nutrients are then absorbed from the intestines into the bloodstream, carried to the liver, and prepared for immediate use or storage for future use. Alcohol ingestion inhibits the breakdown of nutrients into usable molecules by decreasing secretion of digestive enzymes from the pancreas. It impairs nutrient absorption by damaging cells which line the stomach and intestines, and it disables the transport mechanisms for some nutrients so they cannot enter the bloodstream.
Even if some of these nutrients are digested and absorbed, alcohol can prevent them from being fully utilized because it can alter their transport, storage and excretion, e.g. decreased liver storage of vitamin A and increased excretion of fat (Alcohol, 2000). Alcohol can impair the mechanisms for control of blood glucose levels, causing hyper- or hypoglycemia. When no sugar is available from food, and glucose supplies are exhausted, the products of alcohol metabolism inhibit the formation of glucose from other compounds, and as a result, alcohol causes brain damage.
Although alcohol is an energy source, the way the body processes and uses the energy it supplies is more complex than can be explained by a simple calorie conversion (Alcohol, 2000). When alcohol is substituted for carbohydrates, calorie for calorie, subjects tend to lose weight and they derive less energy from the alcohol than they would from an amount of food with the same calorie content. It is not fully understood how alcohol is converted to energy, but several mechanisms have been proposed. Chronic drinking triggers an inefficient system for alcohol metabolism known as the microsomal ethanol-oxidizing syste...