Analyzing Your DNA Raw Data For Alcohol Flush

Drinking Genes: Use your DNA raw data to find out how well you break down alcohol

Alcohol makes people feel good, is a great social lubricant but is alcoholism genetic? DNA raw data from 23andme and other ancestry DNA testing companies can be used to identify how we metabolize alcohol, our risk for dependence and the risk of  ‘caught red faced’ Asian flush.

Our affinity for alcohol is not new, in fact we developed it ten million years ago, even before we evolved to be humans! The natural source of alcohol is fruits, with usually less than 1% of ethanol in ripe fruits, going upto 8% in overripe fruits.

The presence of alcohol was beneficial both for our primate ancestors as well as the plants that bore the fruits. The strong smell of alcohol travelled far and wide, attracting primates. This helped primates reach food source while they helped the plants by dispersing the seeds.


How 23andme raw data can be used to identify risk for alcohol dependence

When our ancestors ate fruits that contained alcohol, they felt good and continued eating, as pleasure centres of the brain were activated to encourage feeding and to help tide over periods of famine. However, this was when fruits were the main source of alcohol, containing only trace amounts in them. In present time, when alcoholic drinks are available in large quantities and are consumed in higher concentrations, problems such as addiction arise .


How fast is alcohol metabolized? Genes involved in alcohol metabolism

Ethanol from the alcoholic beverage is metabolized, predominantly in the liver, by  alcohol dehydrogenases (ADH) and converted to acetaldehyde. Acetaldehyde is acted upon by aldehyde dehydrogenase and converted to acetone.  


What enzyme breaks down alcohol?

There are two types of enzymes associated with the breakdown of alcohol. The alcohol dehydrogenase(ADH) and aldehyde dehydrogenase. Acetate is synthesized with the help of aldehyde dehydrogenases (ALDH), mostly by ALDH2, mitochondrial enzyme, but also by ALDH1, the cytosolic enzyme.


There are 5 different types of ADH enzymes based on structural similarity and kinetic properties.

Class 1 enzymes : The class I enzymes are coded by the ADH1A, ADH1B and ADH1C genes, which are associated with about 70% of the total ethanol oxidizing capacity.

Class 2 enzymes: The class II enzyme is coded by ADH4 gene which is associated with about 30% ethanol oxidizing capacity.

Class 3 enzymes: The class III enzyme is coded by ADH5 gene and is the only enzyme which is detected in the brain.

Class 4 enzymes:  The class IV enzyme is coded by ADH7 gene and is found mainly in the upper digestive tract where it oxidizes ethanol at high concentrations.

Class 5 enzymes: The class V enzyme is coded ADH6 gene is found in a variety of substrates including retinol but it is less efficient in ethanol metabolism.

Alcohol flush reaction:

Some people, about 45% of East Asians, carry a variant of the ALDH2 gene which is associated with an inactive ALDH2 enzyme, resulting in accumulation of acetaldehyde and leading to the flushing syndrome.

Apart from individuals who have an inactive aldehyde dehydrogenase enzyme, individuals who have higher enzyme activity of alcohol dehydrogenase,are also at higher risk of the asian flush or the asian ‘glow’.  Since there is an increased conversion of ethanol into acetaldehyde, again increasing the buildup of acetaldehyde.


Alcohol flush prevention

The redness on the cheeks is a clear give away, which means asian flush reaction prevention tips are often sought out. One of the most sought after is the use of antihistamine for alcohol flush. Experts, however, warn against excessive drinking among people with the asian flush reaction as antihistamines can prevent the cheeks from flushing but the not the buildup of acetaldehyde, which is toxic.


Check your 23andMe raw data or your Ancestry DNA raw data to find out which variant of rs671 you have

TT[Limitation] More likely to show signs of alcohol flush on alcohol consumption
TCModerate risk of alcohol flush on alcohol consumption
CC[Advantage] Less likely to show signs of alcohol flush on alcohol consumption


Check your 23andMe raw data or your Ancestry DNA raw data to find out which variant of rs1229984 you have

AALimitation] Faster conversion to acetaldehyde
More likely to show signs of alcohol flush on alcohol consumption.
AGModerate risk of alcohol flush on alcohol consumption.
GG[Advantage] Normal conversion
Less likely to show signs of alcohol flush on alcohol consumption.


23andMe raw data and ancestry DNA raw data can be used to find out your risk of alcohol dependence, alcohol flush reaction and more, risk of heavy drinking, binge drinking and more. An understanding of your risk will help mould your habit suitably to avoid dependency and risk of disease conditions.

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