How does drinking affect the brain, liver and heart?

The first organ to be affected by your drinking is the brain

No two people will experience exactly the same effect from drinking alcohol, but you’ll usually feel its effect on your brain within minutes. As it passes into your brain, ethanol interacts with the chemicals and pathways that determine your emotions and moods, how you respond to pleasure and pain, and regulate your coordination, movement and even your breathing ⁽²⁾.

Alcohol can make you less inhibited and more relaxed when you drink moderately. However, the more you drink, the more alcohol acts as a depressant. If you drink very heavily in a short amount of time, you may risk passing out. People who become very severely intoxicated can fall into a coma and stop breathing ⁽³⁾. All of these responses involve various regions in your brain.

Research has shown that heavy and abusive drinking over long periods can change the brain’s structure ⁽⁴⁾. Unlike some other organs, the brain doesn’t regenerate so any damage is irreversible. This is also one reason why drinking at an early age is so dangerous. As adolescent brains are still developing, drinking may disrupt how brain connections are formed, particularly those involved in learning and memory ^{(5, 6)}.

Some scientific studies have shown that for some older people, moderate drinking may have a positive effect on how the brain functions. Light and moderate drinking may improve cognition and memory, and help with the mental decline often seen with ageing ^(7-9).

However, these effects don’t apply to everyone and you shouldn’t begin to drink for health reasons. Only a qualified health professional can give you advice by taking into account your drinking patterns, health and lifestyle. Older adults may also need specialized advice about how drinking may affect their brains.

The liver is your body’s main clearing house for alcohol

Most of the alcohol you drink is broken down in your liver in a two-step process ⁽¹⁰⁾. Ethanol in your drink is converted into a compound called acetaldehyde. Because acetaldehyde is toxic to your body, it’s quickly broken down further and eliminated in urine.

How much you drink will seriously affect your liver ^{(11, 12)}. The enzymes in the liver can process roughly one drink every hour, so drinking more and at a faster rate means that acetaldehyde builds up and lingers, causing damage. People who drink heavily for a long time may develop a condition called cirrhosis, where scar tissue builds up in the liver and it stops functioning normally.

How alcohol affects your liver also depends on other factors ⁽¹²⁾. Research shows that being obese and taking certain medications can damage the liver, making it more susceptible to the effects of acetaldehyde. If you’re concerned about the effect of your drinking on the health of your liver, or how it may interact with medications, consulting your health professional is the best course of action to get accurate advice that’s appropriate for you.

Drinking has different effects on the heart depending on how you drink and who you are

Drinking heavily is not good for the heart. In the short term, people who drink excessively can experience an irregular heartbeat ^{(13, 14)} and increased blood pressure ⁽¹⁵⁾ – while, in the long term, heavy drinking can lead to more lasting heart damage that can be life-threatening ⁽¹⁶⁾. People who have certain heart conditions may be advised not to drink alcohol at all.

That said, research conducted over decades supports the notion that for some middle-aged and older adults, drinking some alcohol can be good for the heart ^(17-19). Compared with people who don’t drink, light and moderate drinkers in these age groups have lower cholesterol and less build-up in their blood vessels ⁽²⁰⁾, reducing the risk of heart disease and stroke. But, as with any effect of alcohol, this doesn’t apply equally to everyone. Various factors play a role, including age, gender and overall health. Even small amounts of alcohol may be risky for some people – for example, those on particular medications.

In recent years, some scientists have questioned the benefits of moderate drinking for heart health in older adults – calling into question possible shortcomings in the studies ^(21-23). Where there’s no disagreement among scientists is on the effect that heavy drinking can have on your heart. Drinking heavily over a long time and binge drinking can put you at risk and increase your odds of developing heart disease ⁽¹⁸⁾. Because the effects of drinking are different for everyone, it’s important that you consult a medical professional if you have questions about your drinking and its impact on your heart.