An overview of ethanol metabolism
Ethanol is a polar liquid.
It is water soluble - this means it can pass through biological membranes (like cell membranes) just as easily as water molecules can.
Ethanol is practically insoluble in fats and oils.
The equilibrium concentration of alcohol depends on:
Alcohol will distribute from the blood to all the tissues in proportion to the relative content of water.
Difference between male and female ethanol consumption
Women have an overall smaller volume of fluid in their body compared to males. This means the overall alcohol concentration in the body will be higher in females than males (less water content →higher alcohol concentration).
Absorption of alcohol from intestine to the bloodstream
Alcohol is absorbed in the digestive system - this includes the stomach and the intestines. This is through passive diffusion, where alcohol molecules move from an area of high concentration (intestine walls after consumption) to an area of low concentration (the bloodstream).
Peak alcohol levels is greater if it is all consumed in one large dose than many smaller doses. This may be because there are more molecules to metabolise at once.
Peak alcohol levels are also higher when having alcohol in an empty stomach. The presence of food reduces gastric emptying, as it slows down the consumption of alcohol.
Alcohol Metabolism
90% of alcohol is metabolised in the liver. The remainder is excreted through urination or passed out through the breath.
The enzymes involved in oxidation of alcohol to acetaldehyde include ADH (Alcohol dehydrogenase) and, to a lesser extent, cytochrome P450 dependent oxidising system in the liver, and catalase in the brain.