Most everybody knows that the Asian flush is due to a missing enzyme. Without this precious enzyme, some of us are subject to embarrassing redness that occurs with alcohol consumption. We get laughed and pointed at ("what tribe are you from?" - seriously, someone said this to me), so much so that you can't really go drinking unless you're going with friends you know well or you have miracle pill famotidine (Pepcid). Y'all who don't know that this sh*t gets rid of the redness, y'all know now. (Take 1 hr before consumption.) I have Pepcid at the office, as a purse staple (along with a pen and tampon), and in my backpack so that it's always available should the need ever arise. It's especially important at work functions, where the presence of alcohol is a sign of good times and camaraderie, and you want to JUST FIT IN.
Putting all social embarrassment aside, however, I never realized that the Asian flush could be a sign of something dangerous until a friend sent me this
article. It talks about how by missing this enzyme, you could be at risk for cancer. Here's why. There are 2 enzymes that metabolize alcohol: alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH2).
We Asian flushers have little (heterozygotes for the genetic mutations) or no (homozygotes for the mutation) ALDH2. That means we get a buildup of acetaldehyde, a carcinogen, instead of inactive acetate like in those who don't flush. Acetaldehyde's physiologic effects include flushing, tachycardia, and nausea. That's 3 YES's for me! Several studies have shown a correlation between alcohol consumption in this population and cancer of the oral cavity, pharynx, larynx, and esophagus. Here is a plot of the odds ratio (OR) for just esophageal cancer (EC).
As a light drinker, I have 5.8 times the risk for cancer as someone without the ALDH2 mutation. MEH.
Interestingly, homozygotes for the mutation are at reduced risk because it's as if they're ALLERGIC to alcohol. They can't take any at all; therefore, no cancer. I've known a few of these. As such, most studies have concentrated on the heterozygotes.
 |
| Yokoyama and Omori. Jpn J Clin Oncol. 2003; 33:111-121. |
Please be aware that building up a tolerance to acetaldehyde and the flushing response doesn't mean that the risk for cancer decreases! It just means that you have tolerance now and don't have to worry about the embarrassment anymore. Also, Pepcid may just be addressing the flushing response and not the culprit. I haven't looked into this yet.
To put EC in perspective in terms of incidence:
- Incidence of EC in high-risk China is 20 times that in low-risk western Africa
- The highest rates of EC in the world are along the "Asian esophageal cancer belt," which includes, China, Japan, Iran, and Korea. This extends along the Silk Road, where people did it (ie, genetic mixing)
- I would like to get into this paper for you, Yamamoto. Esophageal cancer incidence in the world. Jpn J Clin Oncol, 2002;32:154, but it's not a free article. :-/
- But I did find this in Hirabayashi Y, Saika K. Jpn J Clin Oncol, 2007;37:893.
What's going on with
SEER black?
36% of Chinese, Japanese, and Koreans have Asian flush. I always thought it was more prevalent than that in Asian populations but often met quite a few that never turned red. Was always jealous. Now I'm also jealous that they don't have to worry about CANCER.
While I tend to ignore a lot of studies that come out in the news, this one seems to hold a bit more weight for me. If you looked into it, probably everything will seem to cause cancer, but there's a long history of evidence here (since the early '80s), and the reported ORs are pretty high. Not to mention I am EXACTLY these study populations.
Well, happy Friday everybody! Time to take my Pepcid - I'm off to happy hour soon.
