Health benefits of moderate alcohol consumption and how much you should drink: what the experts say
A few alcoholic drinks a week has been shown to lower certain cancer risks, help the brain clear away toxins and stave off depression. But it is not always clear where to draw the line, and Hong Kong authorities urge caution
Hongkongers are drinking more alcohol, according to the Department of Health. It published a study last November showing that the percentage of the population that drank had risen from 33.3 per cent to 61.4 per cent in a little over 10 years. But is that all bad?
The department takes a firm line. It warns that “alcoholic beverages are cancer-causing in humans”, with a spokesman explaining that “there is evidence to confirm ethanol associated with the consumption of alcohol is carcinogenic to humans; drinking can cause cancers of [the] oral cavity, pharynx, larynx, oesophagus, liver, colorectum, and female breasts”.
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The spokesman adds: “According to the WHO [World Health Organisation], which warns there are no safe or harmless levels of drinking, alcohol is a causal factor in more than 200 diseases and injury conditions.”
Adding to the discussion, a recent study on “risk thresholds for alcohol consumption” published in British medical journal The Lancet got the world’s attention when it suggested lower limits for alcohol consumption than those recommended under most countries’ current guidelines.
The study spawned a number of eye-catching headlines: “One drink a day ‘can shorten life’,” said the BBC, while The Guardian chimed in with “Drinking is as harmful as smoking.” Yahoo News went with “Alcohol guidelines in many countries may not be safe.”
Data from the study supported lowering current alcohol consumption guidelines to 100g a week for both men and women (one standard alcoholic drink equates to 10g). This is below current UK drinking guidelines – 14 units, or about 140g, per week for both men and women – and, according to the website DrinkIQ, substantially lower than Chile’s 143g a week, Ireland’s 170g, Fiji’s 210g, or Spain’s 280g.
Hong Kong toes a cautious middle ground, advocating a daily limit of 20g for men and 10g for women. The health department warns: “‘Low risk’ is not ‘no risk’. Even within these limits, drinkers can still have problems if they drink too quickly, have health problems, or are older. If you drink, drink sensibly.”
The relationship between alcohol consumption and mortality has for decades been represented by a J-curve. Dr Erik Skovenborg, a Danish specialist in family medicine with a deep interest in the health implications of drinking, describes the curve: “[It] starts with an increased risk of death, especially from myocardial infarction [heart attack], in non-drinkers, [then] a lower risk in moderate drinkers, and an increasing risk of death with increasingly high intake of alcohol.”
This J-curve, Skovenborg says, has been found in a large number of population studies, including from China. Indeed, many studies have shown that a little alcohol is better than none at all, and it is only when moderate drinkers reach the level of having three to four drinks a day that they face the same mortality risk as non-drinkers. This is very different to smoking, for which there is no J-curve: the more cigarettes you smoke, the higher the health risk.
Skovenborg disagrees with the argument that moderate alcohol consumption causes cancer. “Moderate consumption is associated with a reduced risk of some cancers: kidney and haematological cancers, for example,” he says. “The evidence consists of observational studies and is related to an intake of about 30g alcohol a day. [This] observational evidence is overwhelming.”
The health department spokesperson, however, says that while some studies “show that wine – particularly red wine – may protect the heart, as evidenced by the J-curve, this is still controversial”.
Dr Robert Lazzara, founder of US health information network Medical News Minute, does not feel confident that any country’s alcohol consumption recommendations are correct. He is also opposed to the idea that any guidelines should reflect the same amounts for both men and women.
According to one study reported in The New England Journal of Medicine, women absorb up to 30 per cent more alcohol than men do after drinking the same amount. This is for a number of reasons: women’s bodies contain less water than men’s pound-for-pound (alcohol disperses in body water); women usually have lower levels of alcohol dehydrogenase (AHD) in their stomachs and livers than men (AHD breaks down alcohol); and hormonal factors may also play a role in making women more susceptible to alcohol’s effects.
“I believe small amounts of wine, one to two glasses a day, are beneficial,” Lazzara says. “I don’t believe that if you miss a day you should double up the next day.
“The occasional use of alcohol socially, to add to a meal, to enjoy with family and friends celebrating an occasion, enjoying a sporting event, or to relax at the end of the day, is something that I will continue to recommend. Alcohol consumption should always be in moderation, and if you wake the next day with any unpleasant side effects, with which many of us are familiar, I suspect you have exceeded a ‘safe’ level of alcohol consumption.”
Dr Michael Eason, a Hong Kong-based psychologist at MindnLife, notes there are “warning signs” to indicate reckless drinking. People who continue to drink “despite negative consequences” are not controlling it, he says, with those consequences including negative effects on relationships, especially interpersonal relationships, and financial and health problems. He warns that if alcohol is having negative repercussions on any areas of life, then consumption is not being managed properly.
Despite the warnings that came with the study in The Lancet, international studies that analyse the positive effects of moderate drinking keep coming.
In February, Dr Iben Lundgaard and a team at the University of Rochester’s Department of Neurosurgery in New York published a paper in the online journal Scientific Reports examining the effects of alcohol on the brain. They concluded that low levels of alcohol – two-and-a-half drinks a day in a person weighing 70kg – “tamp down inflammation and help the brain clear away toxins, including those associated with Alzheimer’s disease”.
Alcohol, in sensible amounts, has been shown to have positive effects on almost all parts of our physiology. Spanish researchers published a paper in 2012 that concluded moderate alcohol intake – 5g to 15g a day – was significantly associated with a lower risk of depression, specifically when it was consumed in wine. Two analyses by Italian researchers in the 2000s of multiple previous studies confirmed a J-shaped relationship between wine and beer intake and vascular risk (the same relationship was not seen in the case of spirit intake, however).
Most recently, a study published online in the journal Circulation at the end of April examined the impact of healthy lifestyle factors on life expectancies in the US population. It listed moderate alcohol consumption as one of five factors that could prolong life expectancy at age 50 by 14 years for women and 12.2 years for men.
The spokesperson for Hong Kong’s health department cautions that certain other factors should not be forgotten when considering such research, saying that people who make sensible drinking choices probably also “exercise more and have a healthier diet. So, these other factors, or even other hidden causes, rather than [for example] red wine, may account for the better health outcomes.”
But as stated by Dr Kari Poikolainen, author of Perfect Drinking and its Enemies and whose research has focused on the consequences of alcohol intake: “Living is a risky business, but life expectancy of moderate drinkers is longer than abstainers.”
Five tips for drinking sensibly
1. Know your limits.
2. Wine is better than beer, and both are better than spirits.
3. Eat while drinking. Skovenborg says: “If you drink alcohol with food, up to 20 per cent of the alcohol will be metabolised in the stomach by the stomach mucosal ADH.”
4. Having water after each alcoholic drink slows alcohol intake and dilutes what you do drink.
5. Never binge drink.