Written by Eva Hamrud, PhD
February 5, 2021
21 min read
Topic Review: Alcohol
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INTRODUCTION
Most of us drink alcohol. In the UK or Australia for example, about 84% of people drink something each year. In the USA it’s about 69% while in wine-loving France, the proportion of alcohol-drinkers rises to 95%.
People drink for different reasons. Many people drink for enjoyment and socialising with friends. Others drink to relax and unwind from a stressful day. For these reasons, alcohol has played a significant part in shaping human culture for thousands of years. But like with most things, the dose makes the poison.
Excessive alcohol has led to significant health and social impacts. As a consequence, consumption has been trending lower in most advanced nations. That was until a global pandemic hit. Many people have needed a drink in an attempt to overcome the stress, anxiety, uncertainty or isolation imposed on them during 2020.
Despite why people drink, people have claimed all sorts of things about alcohol. The worst from 2020 was the false claim that drinking methanol (the cheaper bootleg version of alcohol) protected you against COVID-19. In Iran hundreds died from this claim that went viral.
Over the years, many other claims about alcohol have been made like “Red wine is good for you” or “Alcohol causes cancer”. Are these true? What is the evidence behind them? And what level of alcohol consumption is safe? This month we asked independent experts from across the globe to review the facts. Here’s what we found…
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META-INDEX
Numbers
15.2 litres of pure alcohol per person consumed each year in Moldova (the highest per capita alcohol consumption in the world)
6.4 litres of pure alcohol as wine consumed per person each year in France (highest per capita wine consumption in the world)
6.9 litres of pure alcohol as beer consumed per person each year in Czech Republic (highest per capita beer consumption for an advanced country)
2,800,000 Premature deaths worldwide caused by alcohol
30.5% the proportion of all deaths caused by alcohol in Russia
3.3% the proportion of all deaths caused by alcohol in the UK, USA and Australia
1920 US outlawed the production and sale of alcohol
1933 US repealed the prohibition ban
95% Share of people drinking over the past 12-months in France
16% Share of people not drinking over the past 12-months in Australia and the UK
ORIGIN STORY
The History of Alcohol
The production of alcohol is one of the oldest processes in human history. Fermentation is the process of transforming sugar by the action of yeast to produce ethyl alcohol (ethanol). Sugars, in the form of glucose, fructose, maltose and lactose can be taken from honey, fruits, sprouting grains – producing mead, wine and beer.
The earliest forms of alcohol production come from Israel – some 13,000 years ago – where brewing wheat/barley-based beer likely served in ritual feasts. There’s still a debate about whether the origins of bread came first or after beer (so far bread is older) – but they were linked.
Although beer was popular amongst Mesopotamia and Eastern Europe – the ancient Greeks shifted to wine. So much so, that citizens and soldiers were averaging 1 bottle of wine per day. Plato and other philosophers in 350BC wrote about the experience of hangovers from their lavish parties. Distilled spirits like brandy, gin and vodka only started to be produced at scale in the 14th century.
Culturally, alcohol has played an important role in human society for thousands of years. “Studies clearly show that there are social and wellbeing benefits to be derived directly from drinking alcohol, especially in relaxed social environments,” says evolutionary biologist Professor Robin Dunbar of Oxford University. “That is why the practice has persisted for so long.” Experts say even innovations and technological developments in agriculture are partly due to the drive to have more quantity of alcohol.
The mind-altering effects of excessive alcohol and the potential to cause social disorder compelled societies to impose controls on unrestricted consumption as far back as 1700BC. From alcohol limits to prohibition, societies have been grappling with how to regulate alcohol consumption. Even in the science, debate continues over what level of consumption is ‘safe’.
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BACKGROUND
Why do we drink alcohol?
People drink alcohol for different reasons, but there is something called the motivational model of alcohol which suggests we drink because we expect a change in how we feel after we drink. In particular, people tend to drink to increase positive feelings or decrease negative ones.
Experts say there are four motivational factors to drink: enhancement (because it’s exciting), coping (to forget about my worries), social (to celebrate), and conformity (to fit in). As we learnt from our review on Habits, there is a combination of genetics and environment that compel us to make something routine.
Is alcohol addictive?
Yes – according to neuroscientists we asked. “Alcohol is an addictive substance for two primary reasons” writes neuroscientist Dr Matt Parker from Portsmouth University. “First, when we drink alcohol, it activates reward chemicals in our brains. Second, alcohol is a depressant, and therefore makes people feel more relaxed. Unfortunately, long term heavy alcohol use causes our body’s stress system to change, making us more sensitive to the effects of stress! So In some people, this can cause them to develop an ‘unhealthy’ relationship with alcohol, using it as a method to reduce stress.”
Sugar may also play a role in contributing to the addictive qualities of alcohol writes Dr Claire Rostron from Open University. “Dopamine, a neurotransmitter involved in controlling reward and pleasure in the brain, plays a key role in motivated behaviour and is also associated with many forms of addiction. Ethanol, like all other known addictive substances, increases the release of dopamine. This can cause you to drink more – why you might want a second, or a third drink, after the first one.
However, after repeated experience with addictive substances like alcohol, dopamine connections can remodel themselves, sometimes decreasing the numbers of receptors that bind dopamine. The size of this reduction is associated with a higher risk of relapse in alcohol addiction.
The fact that ethanol is created from sugars is also likely to increase our propensity to drink. For example, research suggests that some individuals have a predisposition to prefer sugar and this can make them more prone to developing alcohol addiction. Alcohol also seems to act on some of the same brain areas activated by sweet tastes.”
What type of drinker am I?
Dose makes the posion – particularly in relation to alcohol. It’s confusing to try and work out the categories of drinker. Typically, experts define drinkers into 3 categories:
Light Drinker – At least 12 drinks in the past year but 3 drinks or fewer per week.
Moderate Drinker – up to 1 drink per day for women (less than 7 per week) and up to 2 drinks per day for men (less than 14 per week)
Heavy Drinker – more than 3 drinks on any day for women ( 8 drinks or more per week) and more than 4 drinks on any day for men (consuming 15 drinks or more per week).
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THE CONSENSUS
Does alcohol help ease stress and anxiety?
Read the full answers to this question here. Drinking alcohol can be a form of “self-medication” used to unwind from workplace stress or ease study pressures. More than 2,600 years ago the Greek poet Alceus suggested that “we must not let our spirits give way to grief … Best of all defences is to mix plenty of wine and drink it”. Our expert consensus suggests otherwise.
“Stress is biologically mediated by the hypothalamic pituitary adrenal axis – a feedback system between the brain and the pituitary and adrenal glands.” writes Dr Claire Rostron, neuoscientists from Open University. “But acute alcohol consumption can stimulate this, increasing the production of several stress hormones including corticosterone and corticotropin. But the “stress” response also interacts with the reward effects from the dopamine system, so it may very well feel good.”
It’s common for people to have a glass of wine after a stressful day at work. Alcohol has a “depressive effect on the brain… so it often feels like anxiety is helped after a few drinks” writes Mental Health geneticist Dr Alasdair Mackenzie. But it’s a temporary “fix” he says and not really a viable treatment for anxiety. Indeed, after the effects of alcohol wear off, not only are many people back to square one, but their feelings of anxiety can often be multiplied by the after effects of excess alcohol intake.
Alcohol is an anxiety trap writes psychologist Professor Anthony Jorm “because high levels of alcohol use are known to increase anxiety. Alcohol can also lead to social and health problems which can increase anxiety. In general, it is better for people who experience high levels of anxiety to avoid using alcohol” he writes.
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THE CONSENSUS
Does moderate alcohol consumption increase risk of cancer?
88% Affirmative via 17 experts
Read the full answers to this question here. Yes moderate levels of drinking increases your cancer risk – particularly for women (breast cancer) but also cancer of the upper gastro-intestinal tract (including the oesophagus), colon and rectum, liver and larynx. For breast cancer as an example, “there is a 20% increased risk for women consuming moderate amount of alcohol as compared to non drinking ones” writes cancer epidemiologist Dr Matteo Rota from Italy. It’s very important to understand the context of when scientists say an increased risk of cancer – they are referring to relative risk, not the absolute risk.
Relative risk is not the same as absolute risk
A recent study from Australia studied the link between alcoholic consumption and cancer risk amongst 225,000 adults. There was a clear increase in cancer risk with those who drank more than 14 drinks per week (heavy drinkers). “By age 85 years, the absolute risk of an alcohol-related cancer was 17.3% in men and 25.0% in women for those consuming >14 drinks per week”. That sounds alot, but it’s important to know that the absolute cancer risk for those who don’t drink were 12.9% in men and 19.6% in women. This represents an absolute risk increase of 4.4% in men and 5.4% in women. In other words, if 1,000 men and 1,000 women each drank >14drinks per week, around 44 more men and 54 more women would develop cancer as a result, according to the study.
For moderate drinkers who drink one glass of wine per day (moderate drinkers) – the absolute risk increase is not as large. Based on a separate 2019 study, one bottle of wine per week is associated with an increased absolute lifetime cancer risk of 1.0% in men and 1.4% in women.
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THE CONSENSUS
Is red wine and resveratrol good for the heart?
Read the full answers to this question here. Aside from its flavours, wine has gained a reputation as a “healthy” alcohol — with researchers in the past noting associations between red wine drinking in France, and lower incidence of heart disease. However, wine drinking is also known to increase risks of serious health issues, including liver cirrhosis, sudden cardiac death, alcoholic cardiomyopathies and cardiac rhythm disorders. Many suggest that certain phenols like resveratrol (found in grape skins and berries) are the magic ingredient.
Experts were split on this question -most suggesting there is some evidence that red wine while others saying there isn’t enough evidence. Adrian Baranchuk MD from Queens University gives a good overview here.
“Both observational studies as well as clinical trials support the idea that moderate red wine consumption is associated with a decrease in the risk of cardiovascular diseases” writes Dr Eduardo Oliveira, biochemist from Brazil. “Polyphenols present in red wine and ethanol itself are implicated in this effect, and the biological mechanisms include antioxidant, anti-inflammatory and lipid profile effects. Despite this evidence, alcohol is not recommended as a therapy and the abuse of alcohol have the opposite effect on the cardiovascular system.”
Other experts say the positive impact on the heart occurs with alcohol-free wine too. “There seems to be a protective relationship with the coronary arteries only, not with heart failure, stroke etc. However, this favourable relationship is also seen with alcohol-free wine, suggesting it is rather the polyphenols in wine (like resveratrol) than the alcohol per se” writes Dr Rudolph Schutte, epidemiologist from Anglia Ruskin University. A recent review on resveratrol however adds more uncertainty on its potential health benefits – particularly since like many other claimed superfoods (Turmeric) – it is not readily bioavailable to help us in wine. Other research suggests any health benefits come from other anti-oxidant components of red wine.
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DEBATE
Do any health benefits of alcohol outweigh the risks?
This depends on whether the health risk increase outweigh the benefits of drinking (enjoyment, social and fitting-in). For liver specialists and emergency physicians, the risks of alcohol far outweigh any potential health benefit. “No. Even 1 drink per day can increase all cause mortality” says liver expert Professor Ramon Bataller from the University of Pittsburgh.
On the larger population level, large epidemiological studies do show an association between moderate alcohol drinking and good health says epidemioloigst Gideon Meyerowitz-Katz- “but it’s hard to say whether this is because moderate drinking is causing improved health or because people who drink a moderate amount are better off generally than people who either drink a lot or not at all” he writes. “Overall, the balance of evidence seems to indicate that, for most people, any alcohol consumption is bad for your health. There may be some minor benefits, but there are definite risks, so it’s probably going to be negative on balance” says Meyerowitz-Katz.
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GUIDELINES
How much to drink?
“Typically 3 drinks per day in men and 2 in women” is the threshold to cause liver damage says liver expert Professor Ramon Bataller from the University of Pittsburgh. That’s about half a bottle of wine a night – which is classified as heavy drinking. Cancer risks increase significantly beyond the moderate drinker – so authorities vary around the world on guidelines.
The World Health Organization recommends low-risk alcohol consumption of no more than two standard drinks per day with at least two non-drinking days during the week.
In the USA the American Heart Association and the Dietary Guidelines for Americans 2015 – 2020 developed by the United States Department of Agriculture recommends a moderate consumption of alcohol. This equates to up to two standard drinks per day for men and one for women.
In the UK, the NHS has a more detailed and useful overview of what a typical unit of alcohol is here. Like other countries, they say limiting consumption to 14units per week and have alcohol free days is best. That equates to ~1.5 bottles of wine per week.
In Australia, the government guidelines are that healthy men and women should drink no more than 10 standard drinks a week and no more than 4 standard drinks on any one day.
So in summary, having 1-2 glasses of wine a night is within the current guidelines of health.
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THE CONSENSUS
Does alcohol negatively affect brain development in teenagers?
Read the full answers to this question here. Experts say although there is a lot of research on this topic – particularly around heavy / binge drinking – it’s hard to answer this question definitively. “In humans, because we can’t randomly assign some adolescents to drink and others not to, the research is correlational.” writes Neuroscientist Professor Judith Grisel from Bucknell University. “What this large body of research shows is that early binge drinking (i.e., drinking to get drunk) greatly increases the risk for developing alcoholism or other drug use disorders. This is likely because it alters brain development says Professor Grisel.
One study for example, showed that heavy drinking adolescents lose cortical gray and white matter (brain cells and their projections) at rates much higher than normal (there is some natural pruning during adolescence). This study looked at lots of brain regions and the loss was especially profound in the frontal and temporal lobes, responsible for abstract reasoning and learning and memory). There is a good review of much of this research here. This paper summarizes reductions in brain volume, cortical thickness, circuitry as well as the functional implications of these changes. If this isn’t enough, a recent paper demonstrated a link between passing out from alcohol (even one time) and developing dementia says Professor Grisel.
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THE CONSENSUS
Does alcohol help sleep?
100% Negative via 5 experts
Read the full answers to this question here. Alcohol has a hyponotic effect and we seem to become sleepy after a drink. However all experts were unanimous that alcohol is not beneficial for sleep.
“It is a common myth that alcohol helps people sleep” writes Professor Danielle Dick from Virginia Commonwealth University. “Alcohol has sedative properties so it can help people fall asleep, but importantly, the quality of sleep is very adversely affected. Alcohol causes people to wake in the middle of the night and keeps people from entering into REM sleep, which is necessary to get a good night of sleep. Accordingly, even though alcohol may help you fall asleep, you’ll actually get a worse night of sleep overall and be more tired the next day” she writes.
Other experts confirm this. “Alcohol gives the false impression that it helps sleep” writes Dr Abhijit Nadkarni from the London School of Hygiene and Tropical Medicine. **“**What it actually does is to disrupt your Rapid Eye Movement (REM) phase of sleep. REM sleep is the restorative phase of sleep during which we also dream. Disruptions to this phase of sleep leads to poor quality sleep and may cause daytime drowsiness, poor concentration, etc. Thus alcohol is not a useful sleep-aid. Any benefits due to rapid initiation of sleep are offset by the overall poor quality of sleep” he writes.
It’s important to note less alcohol is much better. “There is a dose – response relationship: consuming one glass of red wine close to bedtime is less harmful for sleep than consuming 5 margaritas” writes Dr Christine Spadola from Florida Atlantic University.
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QUICK ANSWERS WITH CONSENSUS
Does alcohol help relieve pain? Possibly as pain-causing signals in the brain can get dampened by alcohol. Unfortunately, research suggests that this pain dampening effect is highly variable and tolerance can occur. Enhanced pain sensitivity may even happen in chronic drinkers.
Does darker alcohol cause worse hangovers? Seems so. Darker alcoholic drinks contain high amounts of substances called congeners which increase the likelihood and severity of hangover symptoms the next day. The effect of congeners though is only part of the hangover story because alcohol and its metabolites also have toxic effects no matter what your tipple.
Is there evidence that light drinking by pregnant women harms their babies? Fetal alcohol syndrome (FASD) is a disease suffered by children that have been exposed to alcohol before birth. Even at low doses, alcohol is likely to cause them lifelong damage. No dose of alcohol has been established to be safe, so avoiding any drinking during pregnancy is the best advice.
Are 12-step programs like AA/NA effective in treating alcohol use disorders? Yes according to the evidence. Most studies suggest that 12-step programs like AA/NA are effective in improving continuous abstinence and long-term outcomes for alcohol use disorders, while other studies indicate a lack of unequivocal experimental evidence for their effectiveness.
Does milk thistle help protect the liver from alcohol damage? There are some studies that suggest that it could be beneficial, yet these results need to be confirmed in large clinical trials. Some studies suggest milk thistle, particularly its component silymarin, may reduce liver injury and oxidative stress caused by alcohol, while other studies indicate no significant effect on liver disease outcomes or recommend further research.
Is half a bottle of wine each night too much? Yes. These studies suggest that half a bottle of wine each night may not pose significant health risks and could be associated with some health benefits.
TOP ANSWER
Does alcohol warm me up?
Claire Rostron: A neuroscientist and expert from The Open University in Neuroscience, Behavioural Science
Not quite. While alcohol can make you feel warm temporarily this is a perception generated by heat sensitive neurons (thermoreceptors) located in your skin that detect a rise in your skin temperature from an increase in blood flow in the vessels close to the skin’s surface. In fact, alcohol actually lowers your core body temperature because the rush of blood to the skin’s surface is a means of body cooling.
So while you may feel warm on the outside, you are getting cold on the inside. Alcohol consumption has also been shown to reduce the perception of cold air temperatures but it is thought that this effect may not come from changes in the dilation of blood vessels but may originate in the brain itself.
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TAKEAWAYS
- There is some evidence that red wine may be beneficial to your heart – but it’s likely not because of the alcohol – might be because of the phenols which can also be found in fruit and vegetables.
- One drink per day for women and two drinks for men is within most guidelines. Realize this will likely increase your risk of developing cancer by ~1% over your lifetime. You decide if that risk outweighs the other lifestyle/social benefits of drinking.
- Liver damage seems to occur in the long-term after about 3 drinks per day in men and 2 drinks for women. Cancer risks increase greatly at this heavy level of drinking.
- Alcohol does not help overcome anxiety or sleep – it may help in the short term, but excessive drinking has the opposite effect.
- Binge drinking has negative consequences for developing brains. As parents, do your best to promote responsible drinking.
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