Question

Moderate Drinking-A School Were Drunkards Graduate

Answer 1

In the ongoing alcohol-and-health debate, the evidence hasn’t been easy to parse. Some studies have suggested that there's a measurable health benefit to having a little alcohol—one researcher even wrote an editorial suggesting that doctors tell their abstaining patients to start drinking a little for the health benefits. But other research has suggested that there’s no truly safe level of alcohol, since even light drinking is linked to health risks, including cancer. A studylast month, for instance, suggested that even the equivalent of a small glass of wine per day is linked to an increased breast cancer risk. And a new study, out in the BMJ this week, throws some more evidence to that side of the debate: It finds that moderate drinking may also not be so innocuous when it comes to brain health.

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Brain scan

As the authors of the new study point out, heavy chronic drinking is linked to Korsakoff syndrome and alcoholic dementia, but not much is known about the effects of lower levels of drinking—particularly “non-dependent” drinking, over time. To examine this question, the authors, from the University of Oxford and University College London, looked at data from the Whitehall II cohort study, which measured, among other variables, how much a person drank over 30 years (people were queried about every five years). Participants, 550 men and women who were not addicted to alcohol, also took cognitive tests periodically, and underwent brain scans with MRI at the end of the study period. The researchers looked for connections between alcohol consumption, cognitive function and brain structure.

It turned out that the heaviest drinkers—those drinking 30 units of alcohol per week—were at significantly higher risk of having atrophy in a brain region called the hippocampus, which is thought of as the most critical area for learning and memory, particularly verbal and spatial. But even moderate drinkers (14-21 units/week) were at a threefold risk of having atrophy in this region. Interestingly, light drinkers (up to seven units/week) didn’t seem to have any benefit over abstainers—they weren’t any increased risk, but there didn’t seem to be any protective effect of light drinking, as other studies have suggested. The study hinted that alcohol may affect the volume of the amygdala, but there were no changes in the prefrontal areas of the brain, which are responsible for higher-level thinking and executive function.

Courtesy The BMJ

What is a unit of alcohol?

For heavier drinkers, there was also a slight drop in the “integrity” of the white matter, the connective tracts between cells that allow neurons to communicate. It’s not totally clear how these physical brain changes translate to function: The only change in cognition was that with increasing alcohol consumption, there was very slight decrease in performance on a test of semantic fluency, which measures how many words a person can generate in a particular category within a certain amount of time. There were no changes in the other cognitive functions tested.

The takeaway of the study seems to be that moderate drinking isn't without its own risks, at least when it comes to atrophy of the hippocampus. The hippocampus generally shrinks with age, and it’s a central area affected by Alzheimer’s disease. So anything that detracts from or contributes to its health as we age is important to be aware of.

It’s worth pointing out that this was an observational study, and the outcome was just a correlation—and despite the fact that the authors tried to control for as many confounding variables as they could, causation still can’t be assumed. There could be some other, as yet unknown, variable that was responsible for the connection between alcohol and brain health. Still, the participants were all living pretty healthy lifestyles, it's also true that the results observed here might be even more pronounced in the general population.

In the UK, where the study took place, alcohol guidelines have already been reduced, based on the accumulation of evidence about the risks. The U.S. has not done such a thing, at least not yet. Whether that will change is still up for grabs. In the meantime, it may be a good idea to keep drinking only very minimally and only if you already do—but to start drinking for the health benefits probably isn't wise. 

“Our findings support the recent reduction in UK safe limits,” write the authors, “and call into question the current U.S. guidelines, which suggest that up to 24.5 units a week is safe for men, as we found increased odds of hippocampal atrophy at just 14-21 units a week, and we found no support for a protective effect of light consumption on brain structure. Alcohol might represent a modifiable risk factor for cognitive impairment, and primary prevention interventions targeted to later life could be too late.”

Answer 2

Moderate drinking can lower the risk of several heart conditions, according to a study that will further fuel the debate about the health implications of alcohol consumption.

The study of 1.93 million people in the UK aged over 30 found that drinking in moderation – defined as consuming no more than 14 units of alcohol a week for women and 21 units for men – had a protective effect on the heart compared with not drinking.

Previous studies have suggested that alcohol has a positive effect on the levels of good cholesterol in the blood and proteins associated with blood clotting.

The research, published in the British Medical Journal, found that moderate drinkers were less likely than non-drinkers to turn up at their doctor with angina, heart attack, heart failure, ischaemic stroke, circulation problems caused by a build-up of fat in the arteries and aortic aneurysm than non-drinkers.

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But the research found that heavy drinking – more than 14 units for women and 21 units for men – increased the risk of heart failure, cardiac arrest, ischaemic stroke and circulation problems caused by fatty arteries.

The authors of the study, from the University of Cambridge and University College London, welcomed the findings but cautioned: “While we found that moderate drinkers were less likely to initially present with several cardiovascular diseases than non-drinkers, it could be argued that it would be unwise to encourage individuals to take up drinking as a means of lowering their risk.

“This is because there are arguably safer and more effective ways of reducing cardiovascular risk, such as increasing physical activity and smoking cessation, which do not incur increased risks of alcohol-related harm such as alcohol dependence, liver disease and cancer.”

Moderate alcohol consumption has long been associated with a lower risk of heart disease compared with abstinence or heavy drinking but the authors described their study as the most comprehensive to date on the relationship.

Non-drinkers were separated from former and occasional drinkers. With previous studies, concerns have been raised that people who have stopped drinking due to illness could have skewed results among non-drinkers.

An independent review of evidence, which formed the basis for last year’s change in the official advice on alcohol consumption, lowering the recommended limit for men from 21 units to 14, making it the same as the guideline for women, found that the benefits of drinking for heart health only apply for women aged 55 and over and the greatest benefit is seen when they limit their intake to about five units a week, equivalent to about two standard glasses of wine. 

The new study found that heavy drinking resulted in an increased risk of a range of heart diseases compared with moderate drinking, but carried a lower risk of heart attack and angina.

The authors cautioned that this did not mean they were less likely to experience a heart attack in future, just that they were less likely to present these conditions at first diagnosis, compared with moderate drinkers. Also, as the study is observational, no firm conclusions can be drawn about cause and effect.

One unit of alcohol is about equal to half a pint of ordinary strength beer, lager or cider (3.6% alcohol by volume) or a small pub measure (25ml) of spirits. There are one and a half units of alcohol in a small glass (125ml) of ordinary strength wine (12% alcohol by volume).

Dr James Nicholls, the director of research and policy development at Alcohol Research UK, said that given the increased risk of other health conditions from drinking, moderate alcohol consumption within existing guidelines was unlikely to curtail or lengthen life expectancy overall.

“While the findings provide convincing evidence for protective effects, the authors sensibly point out that this doesn’t mean it would be wise to take up drinking in order to lengthen one’s life – not least because any protective effects tend to be cancelled out by even occasional bouts of heavier drinking,” he said.

“There are better ways to strengthen the heart such as exercise and good diet. All things being equal – and given the increased risk of suffering other health conditions linked to any amount of alcohol consumption – if you drink within the existing guidelines it is unlikely that alcohol will either lengthen or shorten your life.”

• This article was amended on 24 March 2017. Because of an editing error, an earlier version suggested that the new study had used a definition of moderate drinking based on the current UK guideline of no more 14 units of alcohol a week for both men and women.