Alcohol tolerance refers to the bodily responses to the functional effects of

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...

in alcoholic beverages. This includes direct tolerance, speed of recovery from insobriety and resistance to the development of

alcohol use disorder Alcoholism is, broadly, any drinking of alcohol that results in significant mental or physical health problems. Because there is disagreement on the definition of the word ''alcoholism'', it is not a recognized diagnostic entity. Predomin ...

Consumption-induced tolerance

Alcohol tolerance is increased by regular drinking. This reduced sensitivity to the physical effects of alcohol consumption requires that higher quantities of alcohol be consumed in order to achieve the same effects as before tolerance was established. Alcohol tolerance may lead to (or be a sign of) alcohol dependence. Heavy alcohol consumption over a period of years can lead to "reverse tolerance". A liver can be damaged by chronic alcohol use, leading to a buildup of fat and scar tissue. The reduced ability of such a liver to metabolize or break down alcohol means that small amounts can lead to a high

blood alcohol concentration Blood alcohol content (BAC), also called blood alcohol concentration or blood alcohol level, is a measurement of alcohol intoxication used for legal or medical purposes; it is expressed as mass of alcohol per volume or mass of blood. For example ...

(BAC) and more rapid

intoxication Intoxication — or poisoning, especially by an alcoholic or narcotic substance — may refer to: * Substance intoxication: ** Alcohol intoxication ** LSD intoxication ** Toxidrome ** Tobacco intoxication ** Cannabis intoxication ** Cocaine in ...

Physiology of alcohol tolerance

Direct alcohol tolerance is largely dependent on body size. Large-bodied people will require more alcohol to reach insobriety than lightly built people. Thus men, being larger than women on average, will typically have a higher alcohol tolerance. The alcohol tolerance is also connected with activity of ''

alcohol dehydrogenase Alcohol dehydrogenases (ADH) () are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide (NAD+) to NA ...

s'' (a group of

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

s responsible for the breakdown of alcohol) in the

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it i ...

, and in the bloodstream. High level of alcohol dehydrogenase activity results in fast transformation of ethanol to more toxic

acetaldehyde Acetaldehyde (IUPAC systematic name ethanal) is an organic chemical compound with the formula CH3 CHO, sometimes abbreviated by chemists as MeCHO (Me = methyl). It is a colorless liquid or gas, boiling near room temperature. It is one of the ...

. Such atypical alcohol dehydrogenase levels are less frequent in alcoholics than in nonalcoholics. Furthermore, among alcoholics, the carriers of this atypical enzyme consume lower ethanol doses, compared to the individuals without the

allele An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chrom ...

. An estimated one out of twenty people have an

alcohol flush reaction Alcohol flush reaction is a condition in which a person develops flushes or blotches associated with erythema on the face, neck, shoulders, and in some cases, the entire body after consuming alcoholic beverages. The reaction is the result of an a ...

. It is not in any way an indicator for the drunkenness of an individual. A mild flushing reaction occurs when the body metabolizes alcohol more quickly into acetaldehyde, a toxic metabolite. A more severe flushing reaction occurs when the body metabolizes the acetaldehyde more slowly, generally due to an inactive aldehyde dehydrogenase enzyme. Both of those conditions—faster conversion of alcohol to acetaldehyde and slower removal of acetaldehyde—reduce the risk for excessive drinking and alcohol dependence.

Alcohol tolerance in different ethnic groups

To engage in alcohol consumption and the development of an alcohol use disorder appear to be common to

primates Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians ( monkeys and apes, the latter including ...

, and is not a specific human phenomenon. Humans have access to alcohol on far greater quantity than non-human primates, and the availability increased particularly with the development of agriculture. The tolerance to alcohol is not equally distributed throughout the world's population. Genetics of alcohol dehydrogenase indicate resistance has arisen independently in different cultures. In North America, Native Americans have the highest probability of developing an

compared to Europeans and Asians. Different alcohol tolerance also exists within Asian groups, such as between Chinese and Koreans. The health benefits of a modest alcohol consumption reported in people of European descent appear not to exist among people of African descent. Higher body masses and the prevalence of high levels of alcohol dehydrogenase in an individual increase alcohol tolerance, and both adult weight and enzymes vary with ethnicity. Not all differences in tolerance can be traced to biochemistry however. Differences in tolerance levels are also influenced by socio-economic and cultural difference including diet, average body weight and patterns of consumption.Saggers, S. & Gray, D. (1998b). Dealing with Alcohol: Indigenous Usage in Australia, New Zealand and Canada. Cambridge: Cambridge University Press

Footnotes

References

*Carroll, Charles R. '' Drugs in Modern Society ''. NY: McGraw-Hill, 2000 (fifth ed.). * * * * * Translated from * *

Consumption-induced tolerance

Physiology of alcohol tolerance

Alcohol tolerance in different ethnic groups

Footnotes

References

Further reading