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East Asians have been noted to quickly flush red when drinking due to having a genetic intolerance to alcohol. Researchers have found that the gene responsible for this is spreading to the rest of the population, through natural evolution. The gene makes it hard for people to process alcohol.

Using data from the 1,000 Genomes Project, researchers at the Perelman School of Medicine at the University of Pennsylvania have learned that some people of East Asian ancestry (Korea, Japan and China), as well as West Africans, have a gene variant which acts like an alcohol allergy. This causes them to flush red even after just the first shot. According to Benjamin Voight, an associate professor of genetics and the study’s senior investigator, people with the gene variant may have a reduced tolerance to alcohol.

We didn’t know this about our drinks

Alcohol is processed in the body by first breaking down to acetaldehyde. This toxic substance is an intermediary product prior to being broken down further to acetate, which is less toxic. Due to the genetic variation, East Asians do not easily convert acetaldehyde to acetate, and this causes the accumulation of the former in the body. When this happens, the body has adverse reactions like facial flushing or reddening of the skin, nausea and a rapid heartbeat. Rapidly accumulating acetaldehyde can also lead to discomfort similar to the symptoms of having a hangover.

The gene responsible for this reaction is becoming more common among East Asians and West Africans. One benefit of the gene is that once an individual starts to feel some kind of discomfort, it’s a signal for him to stop drinking. The disadvantage is that there are some individuals who still continue drinking even if their bodies are already telling them to stop.

Another benefit of having a gene which makes you more easily drunk is that it might lower the risk and incidence of alcohol dependence. There is no evidence to show that the mutation is an adaptation developed to protect people against excessive drinking and its side effects. What it does suggest is that there were pressures on early humans which may have influenced the makeup of our genome. These changes may have also created more diversity in traits as well as different susceptibility to modern diseases.

Why we’re often told to drink moderately

The problems from drinking stem from the body’s ability to process alcohol. If a person drinks alcohol slower than the body can process by converting it to acetaldehyde to acetate, then the effects of drinking do not appear as quickly. According to Dr. Sam Zakhari, the National Institute of Alcohol Abuse and Alcoholism director of the metabolism and health effects, alcohol affects the body in different ways, some of which are negative, and some are beneficial, depending on the circumstances.

Dr. Zakhari defines “moderate drinking” as no more than two drinks a day for men, and no more than one drink a day for women. Binge drinking where a person has seven drinks in one day to offset the rest of the week is not considered as moderate drinking.

One drink is equivalent to one bottle of beer, one glass of wine or one shot of  hard liquor. A large glass of wine is equivalent to two drinks. He added that positive results stem from a habitual, moderate consumption of alcohol.

Among the benefits of drinking alcohol is enhanced social interaction. This is especially pronounced when in a party, a social gathering, or at a bar where strangers meet and start conversations amongst themselves. A drink of alcohol can also reduce blood pressure, although excessive drinking can increase it. It also helps to clear arterial fat and reduces the clotting ability of blood.

Certain types of cardiovascular problems can also be prevented by the blood-thinning effect of moderate drinking. Red wine has also been known to reduce blood cholesterol levels. This is why drinking red wine is said to be one of the keys to a longer and healthier life.

With population growth in East Asia and West Africa expanding almost exponentially, the number of people with genetic intolerance to alcohol is also increasing. Today’s bold technologies may be able to address that problem; but until science is able to find a way, it may be best for people of these descents to keep alcohol consumption to a minimum.