In this article, we are going to cover everything you need to know about ALDH2 Deficiency, including symptoms and treatment.
Understanding ALDH2 deficiency is essential if you are someone who gets a flushed red face after you consume alcohol.
This will not only help you drink more comfortably, but also help you avoid serious health risks specific to people with this condition. Let's start by looking at some causes of this issue.
What is ALDH2 deficiency?
ALDH2 deficiency refers to a deficiency in a detoxifying enzyme that makes it harder for the liver to break down some toxins that enter the body.
The typical human liver contains two major aldehyde dehydrogenase enzymes, a cytosolic ALDH1 component, and a mitochondrial ALDH2 component.
Many people, notably about 30% to 40% of East Asian Orientals, have only the ALDH1 enzyme and are deficient in the ALDH2 enzyme.
Being deficient in the ALDH2 enzyme means that your body is less able to safely deal with a particular set of toxins that can enter from the external environment.
One example is the toxin acetaldehyde that enters our body when we consume alcohol. The ALDH2 enzyme is responsible for detoxifying acetaldehyde, so if you're ALDH2 deficient your body will undergo acetaldehyde toxicity whenever you drink alcohol.
This is commonly referred to as alcohol flush reaction or Asian flush (because of the large proportion of Asian people affected).
What causes ALDH2 deficiency?
ALDH2 deficiency is a genetic condition thought to be originally caused by the emergence of rice cultivation in Asia between 7,000 to 10,000 years ago.
A mutation in the ALDH2 gene is thought to be the cause, in that it encodes a form of the aldehyde dehydrogenase 2 protein that is very bad at metabolising environmental toxins like acetaldehyde from alcohol.
A team of researchers headed by Bing Su, a geneticist at the Kunming Institute of Zoology, conducted a study to identify the source of this genetic ALDH2 deficiency.
The team searched for ALDH2 deficiency in 2,275 people across China representing 38 different ethnic groups. They reported that 99% of the people in the southeast region of China had the problem, with less prevalence seen in western China and Tibet.
Notably, the team found a strong geographical correlation between regions with a high prevalence of this issue and archaeological sites in China where rice had been domestically cultivated thousands of years ago. The geographical correlation suggests the potential of a culture-wide dietary catalyst for the gene mutation that causes ALDH2 deficiency.
What are the ALDH2 deficiency symptoms?
The ALDH2 deficiency symptoms can vary depending on the one's sensitivity to the environmental toxin not being broken down.
In the case of alcohol, the specific toxin not being broken down in ALDH2 deficient individuals is acetaldehyde.
When acetaldehyde enters the body it provokes a histamine release that can cause any of the following short-term ALDH2 deficiency symptoms:
- Erythema - redness of the skin caused by increased blood flow to superficial capillaries in the face, neck and upper body.
- Tachycardia - a heart rate that exceeds the normal resting rate.
- Nausea - uneasy feeling in the upper stomach with an urge to vomit.
- Headache - pain in the head often throbbing or pulsing.
This normally occurs 20 to 30 minutes after consuming a sufficient quantity of alcohol and can take up to 2 to 3 hours to subside depending on the individual.
Longer term effects of consistent acetaldehyde exposure include an increased risk of various types of cancers of the esophagus and upper digestive tract.
For more information about common long-term risks facing people with ALDH2 deficiency check out our article titled: Debunking The Asian Flush Cancer Risk.
Should I Get Tested for ALDH2 Deficiency?
The easiest way to test for ALDH2 deficiency is to check if you suffer from the symptoms mentioned above. But after receiving a few emails from customers, we looked into more definitive methods of checking for mutations in peoples genes.
If you finally want to know whether you have this deficiency (commonly referred to as Asian Flush or Asian Glow) there are a few at-home gene tests that you can complete.
This will tell you once and for all if you have this enzyme deficiency, or if your reaction is actually caused by something else. If you really want to know, you will need to buy and complete a genetic test.
However, for most people, experiencing negative symptoms from alcohol is enough to convince them of their ALDH2 deficiency, even if this reaction may be something else, like an allergy to alcohol.
How can I get tested for ALDH2 Deficiency?
Getting tested for ALDH2 deficiency is actually way easier than you'd ever imagine. There are a few reputable companies that will analyze your DNA, and send you back the results.
23andMe is a DNA analysis service providing information and tools for individuals to learn about and explore their DNA.
Quite simply, you send in a saliva sample and they run a full genome analysis on you, uploading the results online.
The test results are (of course!) fascinating, as you will no-doubt found out new things about yourself, and your ancestry that you did not know before.
For the purpose of testing for ALDH2 deficiency, however, we are mostly interested in the part of the report that addresses the ALDH2 gene and alcohol flush reactions.
View a sample of the ALDH2 gene report section here, or sign up via their website to get a full DNA check (we are not affiliated with 23andMe.
A company called ORIG3N offers specific ALDH2 Deficiency tests for $29. This is currently one of the cheapest ways to get this test completed, without having to also test for everything else (like other common DNA tests).
This test will definitively let you know if you have ineffective ALDH2 genes once and for all.
ORIG3N is a company based in Boston, USA and focus primarily on very specific genetic tests for a cheaper price.
They sell tests designed for metabolism, lactose intolerance, skin health and appearance, nutrition and fitness among many others.
This can be really helpful if you want to test for one thing (Asian Flush) without having to pay to test everything else as well.
Determining whether you really need to get tested for ALDH2 deficiency
These tests are easy, but they aren't free. And, some people have their hesitations about sharing their DNA with a huge corporation - and rightfully so!
If you’re really not sure what to do next, it’s best to speak with your doctor. Negative symptoms such as facial flushing can be a real sign from your body that something is wrong.
Your doctor will be able to give you more information about your specific case, what to do next and whether an ALDH2 deficiency test is worth your time and money.
Consuming alcohol should always be done responsibly and in moderation, especially if you deal with an ALDH2 deficiency.
ALDH2 deficiency treatment
After realizing you may be forced to live with this condition, you may wonder about ALDH2 deficiency treatment.
Preliminary research into treating the enzyme issue is ongoing. To date, the most effective treatment for ALDH2 deficiency is detoxification assistance.
Researchers at Stanford University conducted a study that found that a small molecule called alda-89 could increase the ALDH2 enzyme function in ALDH2 deficient mice.
It does this by causing other enzymes to mimic the function of the broken ALDH2 enzyme.
Unfortunately, alda-89 is not safe for human consumption due to its toxicity, but researchers at Standford are hopeful of finding a safer molecule that performs the same function.
Another molecule that has garnered the attention of researchers is ALDA-1. ALDA-1 has been shown in studies to modulate the kinetic properties of the ALDH2 enzyme and increase its function dramatically.
Although not thoroughly tested for safety in human subjects, research is ongoing to determine the therapeutic benefit of alda-1 in treating ALDH2 deficiency.
Saadeh Suleiman of the Bristol Heart Institute, comments that the research is initially exciting but also cautions that human ALDH2 might not be as easy to work with as it is in rats.
So what is the cure for ALDH2 deficiency?
Unfortunately, there is no cure for this issue, it's just about ALDH2 deficiency treatment and management.
To date, the best way to treatment method has been to address the toxicity issue rather than the enzyme deficiency. This method will vary depending on the particular toxin not being broken down in ALDH2 deficient individuals.
As mentioned above, in the case of alcohol the toxin in question is acetaldehyde.
Research has shown that precise supplementation of a combination of compounds can reduce acetaldehyde toxicity and aid the deficient ALDH2 enzyme in metabolizing alcohol — treating the symptoms immediately, rather than preventing them completely.
To find out more check out our article titled: The Science of an Alcohol Red Face and How to Cure it.