Soaking our brains in alcohol

What is the world’s most popular drug? You’d be forgiven for immediately considering it is a substance of questionable legality, whose distribution is underpinned by a shady network of ne’er-do-wells.

But, in fact, the truth is quite different.

Although many people would not think of it as a drug, alcohol is just that  and tops the global list of  psychoactive substances.

Not far behind is caffeine – in your daily cup of joe and other things. But the two substances are worlds apart when we consider the balance of risks and benefits of their use.

Caffeine consumption is generally considered beneficial for brain health. From a cognitive perspective, low to moderate amounts improve vigilance, attention and reaction times. It is less helpful for memory and more complex thinking (executive skills), however, leading to the classic tagline: ‘Drink coffee: do stupid things more quickly’.

Most of the studies that have looked at the longer-term effects of caffeine also suggest it is a good thing, with up to perhaps four cups of coffee per day potentially reducing the risk of dementia.

Coffee is full of antioxidants and so it may not just be the caffeine content that helps, as antioxidants dampen inflammation – a key player in many forms of dementia. There is also evidence (in the lab and in mice, at least) that coffee may bind tau, reducing the negative impact of this Alzheimer’s-related protein, and has been associated with lower levels of amyloid – the other problem protein.

So, I have no problems recommending caffeine, in the form of moderate amounts of coffee and tea, to those trying to protect their brain (though do be wary if you are prone to anxiety or cardiac disease – best to discuss with your doctor).

When it comes to alcohol, though, I am less enthusiastic. As far as the brain health research goes, I still don’t think we have a clear picture.

But as time goes on, the consumption of even moderate amounts is not viewed as favourably as it once was.

A large, recent observational study from the UK showed that compared with those who drank one standard unit (equivalent to one standard glass of wine), those who drank two units per day had brain shrinkage changes equivalent to it being two years older – not a good thing! Going to three per day aged the brain by three-and-a-half years.

There are certain theoretical benefits to imbibing alcohol. These include the antioxidants in certain alcoholic drinks (perhaps especially red wine) and improvements in blood flow. Then there are social benefits and its role for some in reducing stress. But I’m just not sure that it is something we can promote as being good for your brain.

I suspect there is considerable individual variation in how vulnerable the brain is to alcohol.

Those studies that have shown a degree of benefit may have captured those who have more robust brains – ones that can mend or remodel themselves after the toxic impact of alcohol.

This is supported by the notion that people with one or two copies of the apoe4 gene (which, in general, increases the risk of Alzheimer’s disease) are more susceptible to alcohol-related brain problems. We know that this gene variant impairs this mending process.

Ultimately, you must live life, and if you are healthy and enjoy a small drink or two at the end of the day, I’m not going to insist you stop.

But it is good to recognise that it does not automatically promote a healthy brain.

And as a final, non-controversial point: heavy drinking is definitely not a good thing, and you should do your best to address it.

 Kailas Roberts is a psychogeriatrician and author of Mind Your Brain: The Essential Australian Guide to Dementia, now available at all good bookstores  and online. Visit yourbraininmind.com  or uqp.com.au