From the Experts: Asian flush syndrome

While sitting in a bar in Singapore on a Friday evening earlier this month, watching revellers around me celebrate Oktoberfest, the annual German beer festival, it suddenly occurred to me there was a lot of red in the room. Not the furnishings nor the attire of the party-goers, but their faces. Ruby red, cherry red, tomato red; every shade in the spectrum was on display, from a glowing pink to a shade that can best be described as lobster rouge. Sound familiar? Try it the next time you are out painting the town red; count the number of flushed faces in the room. Chances are it will be about half the number of people there. "Oh, it shows that my circulation is excellent," is a common riposte I hear. Another one is: "Proof that my liver is working!" These beliefs are widespread and, unfortunately, dangerously misguided. What is Asian flush syndrome? Asian flush syndrome is, as its name suggests, prevalent in Asia and common in people of Chinese, Japanese and Korean ancestry. The syndrome is caused by variation in two different genes. The first is a variant in the gene that encodes for an enzyme, alcohol dehydrogenase, which breaks down alcohol into acetaldehyde. A whopping 80 per cent of Asians have a gene variant that vastly increases the efficiency of alcohol conversion to acetaldehyde, by up to 100 times. So far so good. The second gene variant is for another enzyme, called acetaldehyde dehydrogenase (ALDH2), which metabolises acetaldehyde, making it less efficient than normal. Acetaldehyde causes blood vessels to dilate, resulting in the characteristic flush, and also raises the heart rate. Breaking down alcohol faster but taking longer to metabolise, acetaldehyde leads to two important consequences. First, you will likely not feel the much-hyped "buzz" that comes with drinking alcohol because your body breaks it down much faster than others. Second, acetaldehyde builds up in your saliva and hangs around in your body for longer than normal because of the second gene variation. And here's the punchline: acetaldehyde is more toxic than alcohol and is a well-known carcinogen. Some people skirt around the issue by taking antihistamines and other over-the-counter drugs to stop themselves from turning red. Even if such self-prescribed drug cocktails work, they only mask the effect and do not treat the cause. This is even more dangerous, because it lulls drinkers into a false sense of security while the acetaldehyde continues to linger in their blood. In fact, research has shown that people who experience Asian flush syndrome have a far greater risk of developing oesophageal cancer and other digestive tract disorders. For example, someone with a single copy of the ALDH2 variant who consumes two beers a day has a tenfold greater risk of oesophageal cancer. Oesophageal cancer is hard to detect and is one of the deadliest cancers. And yet, public education about Asian flush syndrome is desperately lacking. Granted, there have been large efforts to warn the public about the dangers of excessive drinking. However, for those dealt a poor hand in the game of genetics, even moderate drinking could be a potential health hazard. This is compounded by the expansion of the alcoholic beverage industry in Asia. The booming alcohol industry in Asia Alcoholic drinks have a long history in Asia; evidence points to brewing in China from about 7,000BC and in India from 3,000BC. Of the global alcoholic beverage market, the Asia-Pacific comprises a quarter, worth US$258 billion, and is growing at 4.4 per cent annually, according to the consultancy Accenture. Beer is one of the more popular tipples in Asia and, recently, the Asia-Pacific region became the world's biggest beer consumer. According to a BBC report, Asians drank 69 billion litres of beer last year compared to 57 billion in America and 51 billion in Europe. China is now the world's biggest beer producer, brewing 44 billion litres in 2010, twice that of the US at number two. In Southeast Asia alone, alcohol consumption jumped 6 per cent between 2010 and 2011, with Vietnam, Thailand and the Philippines at the top. In Singapore, a report in the Singapore Medical Journal stated that alcohol consumption in the country doubled between 1992 and 2004. The rise in alcohol consumption in Asia is believed to be a direct result of alcoholic beverage manufacturers seeking developing markets for growth now that the American and European markets are saturated. Witness the recent tussle between Heineken and a Thai billionaire over Asia Pacific Breweries (APB). Heineken eventually closed the deal to own 90 per cent of APB, giving it full ownership across Indonesia, Singapore, and Thailand. Identifying the trend for brewery behemoths targeting Asia, Gerard Rijk of financial institution ING Group said to Bloomberg Businessweek: "When you're looking for high growth, Thailand and China are two very crucial markets." Alcohol industry giants aren't afraid to push their product at all costs, even to the detriment of public health, says Mary Assunta of the Consumers Association of Penang. "Transnational alcohol companies use unethical advertising and marketing tactics to get customers, particularly among the lower economic sector of society. Alcoholic drinks are advertised as products which will bring sexual prowess, success and power," Assunta says. Even more disturbing are advertisements that claim health benefits of herbal alcoholic beverages. On television and in print, these drinks are promoted as health restorative tonics, often recruiting celebrities to push their product on an adoring public. These are misleading because they ignore the risks of alcohol consumption, particularly to those with the Asian Flush syndrome. Governments and health care providers need to up their game Excessive alcohol consumption is already a growing public health problem in America and Europe. In Asia, which is now aggressively targeted by the alcoholic beverages industry and where the genetic odds are stacked against a large proportion of the population, I believe the growing risk of alcohol-related diseases is a ticking time bomb. What can we do about it? Firstly, Asian governments need to recognise that there are risks, particular to many of their citizens because of their ethnic genetic predisposition. The alcohol problem needs to be tackled differently from countries elsewhere. Education is paramount. Governments need to communicate the genetic basis of Asian flush syndrome and its associated risks so that misguided beliefs about the rosy glow are dispelled. Efforts need to be sustained for years to educate an entire generation who will then teach their children. Government agencies should track public perception of alcohol and the Asian flush syndrome to monitor the issue. With massive anti-tobacco campaigns rolled out across Asia, governments should apply their anti-smoking strategies to tackling alcohol abuse as well. Singapore slaps a high tax on alcohol to limit consumption but, with incomes rising, the cost of alcohol is less prohibitive than it used to be. Taking on the alcoholic beverage transnationals will be no easy task. These companies sponsor events and perform many philanthropic activities in a bid to boost their soft power and image in the eyes of the public. These efforts also allow them to circumvent limits on direct advertising in mass media. Governments should draw up more restrictive guidelines to control the types of corporate social responsibility activities in which the alcohol giants engage. On the health care provider front, primary care doctors can play an important role in educating their patients. By asking patients about their drinking habits, doctors can monitor the situation on the ground and provide information about the dangers of Asian flush syndrome. Asia has a largely unnoticed public health issue on its doorstep. When the public understands the nature of Asian flush syndrome, they can then make educated decisions on their alcohol consumption habits. Until then, governments and doctors must work together to stave off the problem before it is too late. David Tan is a post-doctoral researcher at the A*STAR Institute of Medical Biology, Singapore. This article was first published in Asian Scientist magazine asianscientist.com