WATCH: The genetic behind alcohol flush reaction
Alcohol has become a part of people’s lives. People drink when they are happy, excited, sad, or stressed out. It is one of the oldest recreational drugs in use. While many people can handle their drink well, some have extremely unpleasant symptoms when they consume even limited quantities of alcohol.
Alcohol Flush Reaction (AFR) is a condition that causes red patches on the skin after consuming alcohol. These red patches are mostly seen on the cheeks, neck, and shoulders. Sometimes, they can also be seen all over the body.
If you have East Asian friends and go out for drinks with them, you may have noticed their faces turning red after just a couple of sips of their drinks.
About 30-50% of East Asians, including Koreans, Chinese, and Japanese experience alcohol flush regularly.
Is alcohol good or bad for health? The controversial aspects of alcohol
According to 100 different studies, moderate consumption of alcohol may reduce the risk of cardiovascular diseases by up to 40%.
The right levels of alcohol consumption also increases healthy High-Density Lipoprotein (HDL) levels in the body
Moderate drinkers may be at a lower risk of developing type II diabetes than non-drinkers.
However, when you consume more than four drinks a day, the risks of alcohol consumption may outweigh the benefits.
Genetically, some people can handle their alcohol better and benefit from moderate drinking. For others, even small quantities of alcohol only cause increased health risks. We will discuss this in the later sections.
The Story Behind Drinking Alcohol
Scientists believe that the alcohol flush reaction has its roots in China about 10,000 years ago. This was the same time that agriculture became a staple form of livelihood here and people’s diet changed. Rice became a common food choice.
According to the experts, the change in diet and lifestyle caused changes in the gene makeup of the Chinese population.
Alcohol flush reaction is a result of such a random change in the genes (gene mutation). It spread from here to neighboring parts of the country and is now very common with East Asians.
It is very rare for non East-Asians to carry this variant (type) of gene.
Alcohol At The Molecular Level- Getting Technical
When you consume alcohol, 90% of its processing happens in the liver. An enzyme called alcohol dehydrogenase converts ethanol into ethanal (acetaldehyde).
Acetaldehyde is a toxic by-product. Another enzyme called aldehyde dehydrogenase quickly converts this by-product into ethanoate (acetate).
Before the liver starts processing alcohol (in about 20 minutes after consumption), alcohol is absorbed from the stomach to the bloodstream and reaches the whole body, including the brain.
Some people experience alcohol flush and others don’t because of their genes.
What happens in people with alcohol flush?
In people with alcohol flush, the body does not produce enough aldehyde dehydrogenase to convert acetaldehyde to acetate. This causes excess accumulation of the toxic acetaldehyde in the body. This leads to the symptoms of alcohol flush including skin blotching, nausea and general feeling of discomfort.
How does alcohol affect your brain?
Alcohol reaches your brain within minutes after you have had your drink.
Your Central Nervous System (CNS) helps with processes like thinking, reasoning, understanding, and motor functions. Alcohol slows down the CNS processes. People experience a foggy mind, inability to remember things, slowed motor functions, and dull hearing after they start drinking because the alcohol affects the nerve cells and makes them slow.
How fast alcohol affects your brain’s activity can depend on factors like what other drugs you have had before, your age, size, and gender and also your genes.
Did You Know?
If you are a woman, then you are at a higher risk for developing alcohol-related disorders than a man! It sounds unfair but this is true.
Drinking the same amount of alcohol as a man seems to damage the woman’s health more than it does a man’s.
When it comes to alcohol disorder-based deaths, women have 50-100% more mortality rate than men.
Women have lesser water content in their body than men. So, the concentration of alcohol in the body of a woman is higher and they get intoxicated faster.
Because of the presence of estrogen, more women experience liver damage because of excess alcohol consumption than men.
Recommended Values
The U.S. Dietary Guidelines for Americans suggest the below recommended values for moderate alcohol consumption.
Adult men – 2 drinks a day
Adult women – 1 drink a day
The recommended values are for normal adults without alcohol flush or alcohol abuse conditions.
People with alcohol flush reactions will have to limit their alcohol consumption based on how intense their symptoms are.
What Happens When You Consume Excess Alcohol?
The Body Alcohol Content (BAC) is a measure of how much alcohol has reached your Central Nervous System (CNS). BAC is measured in terms of percentage of alcohol in 100 ml of blood. Below are the values of BAC and their corresponding symptoms.
Alcohol flush is one of the earliest symptoms of alcohol consumption.
Here are the symptoms of alcohol flushing:
- Flushing/redness in face and skin
- Nausea and vomiting
- Rapid heart rate
- Redness and itch in skin
- Headaches
- Dizziness
What Happens During Alcohol Withdrawal?
Alcohol is a drug and depending on the tolerance levels and the years of alcohol use, symptoms of alcohol withdrawal may include:
- Anxiety
- Irritability and mood swings
- Fever and nausea
- Hallucinations
- Delirium Tremens (irregular heartbeat, hallucinations, confusion, and shivering because of alcohol withdrawal)
People with alcohol flush reaction are not usually prone to overusing the drug as the side effects discourage them from drinking more.
Non-genetic Factors Causing Alcohol Flush
- Age – People with alcohol flush reaction show severe symptoms when they first start drinking. The severity of the condition reduces as they grow older.
- Ethnicity – People of East Asian ancestry are more prone to developing alcohol flush reaction.
- Social pressure – The social pressure to drink with friends, family, and colleagues can make a person drink more than what he/she can handle. This can intensify the symptoms of alcohol flushing.
Genetic Association
Genetics play an important role in determining whether or not your body can handle alcohol.
The ALDH2 gene helps produce aldehyde dehydrogenase (ALDH) that converts the toxic acetaldehyde from alcohol into acetate. This step is very important to prevent acetaldehyde accumulation in the body that leads to alcohol flush.
Recommendations For Those With Alcohol Flush Reaction
- Know your limit – Start with very little quantity of alcohol and stop when you start getting uncomfortable. Symptoms can start anywhere from 1-60 minutes after consuming a drink.
- Choose the right drinks – Prevent choosing drinks with high ABV. Red and white wine, sparkling wine, and beer are safer options if you want to drink.
- Keep your stomach full – Eating before and during drinking can prevent the alcohol from getting absorbed quickly into your system. This can bring down the intensity of the alcohol flush reaction.
- Keep your body hydrated – Drinking water in between can help reduce the concentration of alcohol in the body and prevent the onset of rapid symptoms.
- Know if it is alcohol flush – Sometimes, alcohol allergy can also cause similar symptoms like alcohol flush. A simple genetic test will tell you if you have the condition or not.
- Consider medications – Your doctor can prescribe topical creams like Brimonidine and drugs like histamine-2 (H2) to prevent the unpleasant side effects of alcohol flushing.
Summary
Alcohol flush reaction is a condition that causes red patches in the skin, nausea, and general discomfort after a person drinks. This condition is very common in people with East Asian ancestry. As the person continues to drink, the symptoms get worse. Genetics play a very important role in causing alcohol flush reactions. Knowing your limit, choosing alcohol with lowered ABV and keeping the stomach full and the body hydrated all help bring down the intensity of the condition. Certain medications can help too.
References
- https://www.nationalgeographic.com/magazine/2017/02/alcohol-discovery-addiction-booze-human-culture/
- http://sciencenetlinks.com/student-teacher-sheets/alcohol-and-your-brain/
- https://www.nm.org/healthbeat/healthy-tips/alcohol-and-the-brain
- https://www.cdc.gov/alcohol/fact-sheets/moderate-drinking.htm
- https://www.alcoholrehabguide.org/alcohol/effects/
- https://medical.23andme.com/wp-content/uploads/2018/01/Alcohol-Flush-Reaction.pdf
- https://www.nycpainspecialists.com/blog/2020/2/13/the-science-behind-the-asian-flush
