Alcohol facts

Alcohol is one of the most widely used social drugs in the world. It is a depressant that slows down the messages travelling between the brain and the body. The riskier a person’s drinking, the more likely it is to cause serious health, personal, and social problems.

Heavy drinkers, binge drinkers, and very young drinkers are particularly at risk. How alcohol affects you can vary with your age, size, weight, current health, and other risk factors. Binge drinking is a particular problem among younger people, but anyone who drinks heavily and often, or drinks too much in one session, risks both immediate and long-term harm. The risk of injury and disease rises the more you drink.

How much is lower risk?#

The less you drink, the lower your risk of alcohol-related harm. For some people, not drinking at all is the safest option, and there is no level of drinking that is completely safe. To reduce risk, commonly recommended limits suggest that healthy adults drink:

• no more than about 10 standard drinks a week
• no more than about 4 standard drinks on any single day

Children and young people under 18 should avoid alcohol entirely, as there is no safe level for them. Drinking is also not recommended during pregnancy, when planning a pregnancy, or while breastfeeding. Drinking above these levels carries a higher risk, and the more you drink, the higher the risk becomes.

Mixing alcohol with other drugs, whether illegal drugs or some prescription medicines (known as polydrug use), can also cause serious health problems.

Standard drinks and how to keep track#

Different alcoholic drinks contain different amounts of pure alcohol, which can make it tricky to keep track of how much you are actually drinking. In many places a “standard drink” is defined as containing about 10 g of pure alcohol, and a single serving is often more than one standard drink.

The size of a standard drink varies by:

• Type of alcohol: some cocktails can contain as much alcohol as 4 standard drinks despite being a smaller volume than a glass of beer.
• Brand or label: wine, for example, varies considerably in strength, usually between about 9% and 16% alcohol.
• Where you are: serving sizes differ between bars, restaurants, and what you pour at home.

As a rough guide, one standard drink is roughly equivalent to a small glass (about 285 ml) of regular beer (around 4.8% alcohol), a slightly larger glass (about 375 ml) of mid-strength beer (around 3.5% alcohol), or a small glass (about 100 ml) of red table wine (around 13.5% alcohol). To keep track, count your standard drinks and read product labels, which list the number of standard drinks a container holds.

How the body processes alcohol#

Alcohol is absorbed into the bloodstream from the stomach and small intestine. Food in your stomach slows absorption but will not stop you becoming drunk; eventually all the alcohol you drink reaches your bloodstream. Most of the alcohol in the body (about 91%) is broken down by the liver, and a small amount leaves in urine, sweat, and breath.

Because the liver can only break down roughly one standard drink an hour, sobering up takes time. Cold showers, exercise, black coffee, fresh air, and vomiting will not speed up the process.

Effects of alcohol on your health#

Drinking can affect many of the body’s systems, including:

• cardiovascular system: raised blood pressure and triglycerides (especially after binge drinking), damage to the heart muscle, and stroke
• nervous system: nerve and brain damage, tremors, and dementia
• mental health: alcohol can worsen conditions such as depression or anxiety and increase suicide risk
• gastrointestinal system: stomach inflammation (gastritis) and bleeding
• liver and pancreas: hepatitis (inflammation), fatty changes, cirrhosis, liver failure, and liver or pancreatic cancer
• endocrine system: reduced fertility, loss of libido, and problems controlling blood sugar
• weight gain, which can lead to obesity and raise the risk of diabetes
• cancers, including bowel, breast, throat, and mouth cancer

Alcohol, young people, and pregnancy#

Alcohol can affect how the brain develops in people under the age of 25, and teenagers under 18 are particularly at risk.

Drinking during pregnancy can increase a baby’s risk of being underweight, premature, or born with a range of developmental, behavioural, and physical effects known as fetal alcohol spectrum disorder (FASD). Even a low intake at any stage of pregnancy could be harmful, so alcohol is not recommended during pregnancy or if you are planning a pregnancy.

Alcohol and breastfeeding#

Alcohol can reduce breastmilk supply and can pass to your baby through breastmilk, where it may harm their developing brain. Current evidence suggests there is no safe or no-risk level for breastfeeding mothers, so it is best to avoid alcohol. If you do choose to drink, waiting about 2 hours after each standard drink before breastfeeding can help reduce the amount that reaches your baby (for example, wait about four hours after two standard drinks).

Binge drinking#

Binge drinking describes heavy drinking over a short time to become intoxicated. The effects of large amounts of alcohol are immediate and severe, and may include confusion, blurred vision, poor muscle control, impaired judgement, nausea and vomiting, and, in serious cases, deep sleep, coma, or even death. Impaired judgement makes you more likely to do something dangerous. If you binge drink, your melatonin levels can be affected for up to a week.

Alcohol and driving#

Alcohol impairs coordination and judgement and is a major cause of road injury. It is safest to avoid alcohol completely if you need to drive or operate heavy machinery.

There is no set number of drinks that guarantees you will stay under a given blood alcohol concentration (BAC). The rate at which alcohol is absorbed varies with body size, age, sex, body fat, amount of food in the stomach, liver health, alcohol tolerance, the strength of the drinks, and any medications. You might drink the same amount on two occasions and reach completely different BAC levels.

• If you do drink and then drive, keep your BAC under the legal limit where you live.
• Alcohol takes time to leave the body. After a night of drinking you may still have alcohol in your system for several hours, or into the next day.
• Some drivers, such as learner and probationary drivers and drivers of trucks, buses, and trains, are often required to maintain a zero blood-alcohol limit.

It is difficult to know exactly how many drinks will keep you under a limit. Personal breath-testing machines may give an incorrect reading if they are not properly calibrated, which can be dangerous. Even if a breathalyser suggests you are under the limit, your BAC can keep rising after your last drink and push you over while you are driving.

Benefits of cutting down#

Reducing your alcohol intake, or not drinking at all, can bring quick benefits to your health and lifestyle:

• Better sleep: alcohol is a depressant that disturbs sleep, so even though it can make you fall asleep faster, overall sleep quality is often poor.
• Healthier skin: alcohol can leave skin looking and feeling dehydrated and can cause redness and broken capillaries.
• Improved mental health, with more clarity, better concentration, and more energy.
• Better immunity, and a lower risk of alcohol poisoning, hangovers, and dehydration.
• Weight benefits: many alcoholic drinks are high in sugar and calories, and alcohol can trigger cravings for less healthy foods such as salty snacks.
• Cost savings, both on alcohol and on a night out.

Remember, you don’t have to drink alcohol to have a good time.

Drinking more responsibly#

If you want to drink less at an event or on a night out:

• Don’t drink before you go out, and set a limit beforehand and stick to it.
• Eat before and while drinking to slow absorption, and avoid salty snacks that make you thirsty.
• Make every second or third drink non-alcoholic, or try low-alcohol options.
• Start with a non-alcoholic drink, and don’t take part in rounds or let others buy your drinks.
• Always keep your drink with you to reduce the risk of drink spiking.
• Stay within recommended lower-risk limits.

Key points#

• The riskier someone’s drinking, the more likely it is to cause serious health, personal, and social problems.
• Heavy drinkers, binge drinkers, and very young drinkers are particularly at risk, and the risk of injury and disease rises the more you drink.
• There is no completely safe level of drinking, but staying within commonly recommended lower-risk limits reduces harm.
• It is safest to avoid alcohol entirely during pregnancy, when planning a pregnancy, while breastfeeding, and before driving.
• The liver clears only about one standard drink an hour, so sobering up takes time and cannot be rushed.

Where to get help and trusted information#

For evidence-based global health guidance, see Source: World Health Organization (WHO).