Kane Lo flushes when he drinks, and while his mates might laugh at his red face and bloodshot eyes, they can’t see the rash spreading across his chest or the throbbing headache kicking in.
“It’s pretty severe,” the Melbourne-based digital analyst says.
“If I wasn’t drinking, I would be concerned enough to go see a doctor.”
Mimi Zhu, a queer Asian-Australian writer living in the United States, experiences similar symptoms.
“The first time I ever drank alcohol, I remember my heart beating super quick,” they say.
“Then I felt really dizzy. I started breaking into hives.”
Alcohol doesn’t give me a rash and I don’t always flush red, but it often lifts my heartrate and brings on a headache.
The older I get, the worse it feels, and that’s made me curious about what Asian flush really is and whether anything can be done about it.
Why does ‘Asian flush’ happen?
“Asian flush describes a physiological response that individuals have to alcohol,” explains Terry Mulhern, associate professor in biochemistry and molecular biology at the University of Melbourne.
It’s thought that more than one in three people of East Asian heritage (Japanese, Chinese and Korean) flush after drinking alcohol, with varying severity.
This response can be attributed to how your body processes alcohol.
“Alcohol gets broken down in two steps by our liver — first from ethanol to acetaldehyde, and then from acetaldehyde to acetate. Essentially, it goes from alcohol to vinegar,” Dr Mulhern explains.
This process involves two different enzymes.
“Alcohol dehydrogenase … the [enzyme] that turns ethanol, or alcohol, into acetaldehyde, that’s the first step,” he says.
“The second step is an enzyme called aldehyde dehydrogenase. That’s the one that causes the problem for a lot of East Asian individuals.
“They carry an inactive version of that enzyme, so they get a big build-up of the middle product in the pathway.”
That product, acetaldehyde, is a toxin which can trigger the symptoms of Asian flush.
“It causes histamine release,” explains Dr Mulhern.
“It’s not an allergic reaction, but it causes a downstream effect like an allergic reaction, like flushing, sweating and red face.”
Dr Mulhern says we inherit the gene responsible for producing aldehyde dehydrogenase from our parents; “one from your mum, one from your dad.”
That means we can inherit one of three outcomes: one faulty enzyme from one parent and one normal enzyme from the other; two faulty enzymes; or two normal enzymes.
“Individuals … who’ve inherited an inactive enzyme from both parents, will definitely suffer the strongest response,” he says.
Trying to avoid the flush with antihistamines and drink choices
There are plenty of ways people try to avoid or minimise flush, but do they actually work?
Kane avoids drinks with certain colours because he believes they trigger stronger flush symptoms.
But Dr Mulhern says “it’s true that they might be experiencing different effects from different drinks, but it’s not a difference in their acetaldehyde response. It’s an additional response to other colours and flavours in those drinks.”
He adds: “It’s going to be on top of the Asian flush they might be experiencing.”
Others use antihistamines to minimise symptoms while drinking, which Dr Mulhern says are only effective on a surface level.
“They will treat the flushing part and some other symptoms associated with that histamine release,” he says.
“But they’re not doing anything to the acetaldehyde. You’ve still got acetaldehyde in your system doing its nasty toxic stuff, but you just don’t have a red face.”