Sunday, 27 February 2011

SOS: Save our Science - Drink Hearty Lads (and Ladies)

ResearchBlogging.orgHi Everyone. Hope there's still people out there reading this. Would be great to hear from you. Sorry things have been a bit slow, there's a lot going on this term, which I hope to write about (in part) soon. This new rotation is really fun, although quite long hours, and I've got loads of other projects going on relating to Science Communication, as many of you may already be aware. It means I'm not getting much time to sit and write articles on here though. I will be working hard to try and get back to ClearSci as much as possible, so hopefully more will be going on around here.

Anyway, so here's a fun story that is an issue I've been looking forward to having a go at. Everyone always has some new story about how alcohol is good for you or bad for you, and usually it depends on what you measure and whether it's the alcohol itself or something else (e.g. tannins in red wine) which is helping you out. This latest is cool because it pulls together a lot of research from the last 30 years, and actually finds some benefits, in certain instances, but also points out the importance of moderation. Enjoy. :)

This is a debate that I find quite interesting, especially since everyone seems to be more than a little biased in their desired outcome. It is the endless search for positive effects of drinking alcohol. A new meta-analysis (re-examination of lots of old data from different studies) of alcohol research may finally be able to put part of this issue to rest.

The news is full of stories telling us that alcohol is good for you… or is it bad for you. Stories like this give everyone the impression that science is inconsistent and transient. Makes it sound like scientists are so busy disagreeing with each other that they’re not really making any progress. This is a prime example of the misreporting of science.

Whilst different studies do disagree on whether alcohol is beneficial or detrimental, this is usually because each study measures different things in different ways. Particularly when performing research with humans, where every aspect of life cannot be controlled, it is very difficult to draw reliable conclusions. For example, people with a lower alcohol intake may live more healthily in other ways; eating better or exercising more. These are called confounding factors, as it is difficult to determine whether what you are measuring (“health”) is the result of what you’re interested in (alcohol) or is a product of more general lifestyle differences.

In addition, different research focuses on different effects of alcohol intake. This newest research is particularly interested in the effect on cardiovascular (heart/blood) diseases, specifically Coronary Heart Disease, Cardiovascular Disease and Stroke. Others have been more interested in the effects of alcohol on cancer risk or blood pressure. The results of these are often generalised to “good for you” or “bad for you” but obviously have many different connotations.

The newest research from a Canadian group combines data from 84 different trails published over the last 30 years and includes around 3 million people. It uses measurements of the effect of alcohol intake on incidence and death as a result of different cardiovascular diseases. The combined data, many are pleased to note, suggests a slight benefit from moderate alcohol intake. Risk of coronary hear disease could be reduced by up to 25% and overall mortality was observed to be reduced by around 10% in groups of alcohol drinkers compared to non-drinkers.

However, alcohol does not seem to protect you from strokes. Closer analysis of this data showed that whilst alcohol does slightly help to prevent ischaemic strokes, it increases the risk of haemorrhagic strokes. This is likely to do with the anti-clotting effect that alcohol seems to have in the blood. Similarly, other researchers have previously found that alcohol does not help to prevent cancers.

The team accompanied these findings with a second paper, exploring the effects of alcohol in biological systems at a molecular level, which appears to show that alcohol can help to reduce the occurrence of key markers of cardiac diseases.

It is emphasised that benefits were only observed at low alcohol intakes, typically around 2.5-14.9g of alcohol per day, which equates to roughly one alcoholic beverage per day. Significantly higher alcohol intake may almost double your chances of falling ill.

This data is all the result of observational studies on humans, so cannot ever prove a direct link between alcohol and health benefits. These findings are also not general advice to everyone, as alcohol has many other damaging consequences; the team states that the benefits of alcohol to heart disease much be balanced, in each case, against the risks. As an example, younger people are more likely to be seriously injured as a result of drinking and have much lower risk of coronary heart disease.

In the future, the team suggests, research should begin to investigate the mechanisms by which alcohol acts to affect wellbeing. We should also be working to identify which groups of people are most likely to benefit from alcohol. This would allow for a future where, under certain circumstances, for certain people, your doctor could recommend a drink per day as being good for your health.

Ronksley, P., Brien, S., Turner, B., Mukamal, K., & Ghali, W. (2011). Association of alcohol consumption with selected cardiovascular disease outcomes: a systematic review and meta-analysis BMJ, 342 (feb22 1) DOI: 10.1136/bmj.d671

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