The Truth About Booze: How Alcohol Really Affects your Body

Birds do it, when they eat berries that have fermented in the first frost. Bees do it, when they suck on tree sap, and “many kinds of monkeys”, noted Charles Darwin in The Descent of Man, “have a strong taste for spirituous liquors.” There is evidence that humans were brewing their own booze even before the wheel caught on, but how much do we know about how it works on our brains and bodies? 

Well, quite a bit. Recent decades have seen dozens of studies validate some old sayings, debunk others, and give the medical establishment a much clearer understanding of how alcohol affects us and how much it is really OK to drink.

You may have noticed that the effects of your first drink kick in almost as soon as it hits your mouth, but that may be more to do with your expectations than the alcohol itself. “Most people, the first time they drink, find it horrible,” says Professor David Nutt, the chair of Drug Science, an independent UK scientific body researching drugs and alcohol. “But, eventually, they come to associate the smell and taste of their favourite drink with the effect in the brain and the pleasure that’s coming.”

THE first sip

From the mouth and gullet, the liquid moves to your stomach, where about 20 per cent is absorbed through the stomach lining. The rest is absorbed once it reaches the small intestines, all of it ultimately ending up in your bloodstream. Food can act like a sponge and slow the alcohol’s absorption: if you are drinking on an empty stomach, few minutes after your first sip, once it gets to your bloodstream and into your brain, it starts to have an effect.

The session

As you keep drinking, dopamine kicks in. This is the ‘seeking hormone’ that is often associated with the drive to do things, rewarding us with a little feelgood spike whenever we think about it. Alcohol affects the prefrontal cortex, which primarily governs cognitive control, impulse behaviour and the brain’s memory centre. This means that your judgment becomes impaired and movement is disrupted.

If you drink too much, your liver starts to feel the strain. “On average, the liver can only metabolise, or break down, roughly one small glass of wine or a pint of beer an hour,” says nutritionist Hannah Macey. “When more than this is consumed, your liver becomes unable to deal with the workload so it begins to send alcohol to the heart. This leads to a fall in your blood pressure, while the newly alcohol-rich blood is now pumped to the lungs.” This means that you exhale some of your intake, which, of course, is how Breathalyser tests work.

The morning after

While there is no single commonly accepted cause of hangovers, several bad things tend to happen in combination after a big night out. “Dehydration is common,” says Macey. “But alcohol can also irritate the stomach lining, potentially causing diarrhoea, vomiting and an imbalance of electrolytes including sodium, potassium and magnesium, which the body needs to function well. Together with blood vessels in the brain expanding, this can all cause a thumping headache.”

It is not just the headache: overdoing it inhibits the liver’s normal ability to release sugar, leading to the sluggish feeling that comes with low blood sugar levels. The body also reacts to what it perceives as an imbalance in brain chemicals, and tries to correct it by reducing Gaba , our main inhibitory neurotransmitter, — which can cause what many drinkers think of as “hangxiety”. Finally, even one drink will negatively affect sleep, and having a few means you are unlikely to have had much beneficial sleep.

The fix? It is everything you know you should do, but don’t: eat before you start boozing to slow the absorption of alcohol into the blood, and drink plenty of water before, during and after drinking. The morning after, take an electrolyte supplement to replace what you have lost, eat anti-inflammatory foods containing omega-3 fatty acids. For a slightly more kill-or-cure option, a cold shower might help.

The medium term

The ill effects mentioned above can build up, leaving you overstressed, short on sleep, and with high blood pressure. Regular consumption can cause permanent dilation of blood vessels and weight gain. As well as the significant calories lurking in alcoholic drinks, there is some evidence linking moderate consumption of alcohol to the buildup of visceral fat around the waist, associated with a number of health risks, including cardiovascular disease and type 2 diabetes.

Over the medium term, booze can also kill off the helpful bacteria in your gut to an extent that can affect your immune system and mood, the latter enough to make you likely to drink more. “This can lead to a hindered immune response, negative gut symptoms and higher levels of stress, anxiety and depression,” says Macey. “It also plays havoc with our hormones, which can lead to increased hunger and diminished sex drive.”

The long haul

One of the better known health consequences of long-term alcohol consumption is liver disease. Although cirrhosis can take years to develop, regularly drinking over the recommended limits can damage the liver. Meanwhile, cutting down on drinking has become standard advice in lowering the risk of dementia. While alcohol doesn’t appear to directly kill brain cells, it can disrupt the growth of new ones — and also indirectly cause neurological problems that can lead to dementia.

Still, a glass of wine a day might help your longevity, right? Well, unfortunately, rumours of booze’s effectiveness in that area may have been exaggerated. 

It seems fairly clear that there is nothing in alcohol that is directly beneficial: resveratrol, an antioxidant often credited with health-boosting properties, is only present in minuscule amounts in red wine. Despite this, people who have a drink or two every week aren’t necessarily likely to experience worse health outcomes. A recent meta-analysis that considered results from 107 studies found that, compared with never drinking, low-volume drinking is not associated with an increase in all-cause mortality.

If you don’t want to give it up entirely, perhaps the trick is to balance the (relatively) small health risks of low consumption against the fact that having a glass of red with some friends remains a lot nicer than the other health risks we are routinely exposed to. “Alcohol is the best drug for socialising that we know of,” says Nutt. “And the whole history of humanity is socialising — we’re an enormously social species and alcohol facilitates that. The problem is that about 10-15 per cent of people really struggle to control their drinking and quite a few people drink more than they should without knowing it.” Nutt suggests two things. “First, you should be aware of how much you drink, in the same way you’re aware of your weight and waistline, and try to reduce it if necessary.” The second point may take some practice: “Never have a drink that doesn’t give you value. Most people have one drink and carry on – but most of the value comes from that first drink.”