Alcohol: How it impacts the body while you’re drinking and over time

Drinking alcohol can have profound effects on the brain and body, both while you’re drinking and over time

From the moment you take a sip, drinking starts to influence your biology. Illustration: Montse Galbany/New York Times
From the moment you take a sip, drinking starts to influence your biology. Illustration: Montse Galbany/New York Times

Drinking alcohol can have profound effects on the brain and body. In the moment, some of those effects can be pleasurable. But in the long term, especially when it’s consumed in large quantities, alcohol can cause serious health problems.

Here’s an inside look at what alcohol does to the body, both while you’re drinking and over time.

Brain

Drinking temporarily increases levels of the neurotransmitter dopamine, which is partly why people feel good when they have a few drinks. Illustration: Montse Galbany/New York Times
Drinking temporarily increases levels of the neurotransmitter dopamine, which is partly why people feel good when they have a few drinks. Illustration: Montse Galbany/New York Times

Alcohol has a rapid effect in the brain, causing people to feel more relaxed and sociable.

Over the long term, alcohol use is associated with changes in brain structure. Some studies have found that middle-aged and older adults who average even one drink a day tend to have slightly less brain volume than people who don’t drink. And the more alcohol someone consumes, the more the brain shrinks. Experts don’t know exactly why that is, but one theory is that alcohol alters the brain’s immune system, ramping up inflammation, which can damage neurons.

Mouth and neck

Alcohol is primarily metabolised in the liver, but the process also occurs in the digestive tract. Illustration: Montse Galbany/New York Times
Alcohol is primarily metabolised in the liver, but the process also occurs in the digestive tract. Illustration: Montse Galbany/New York Times

The tissues that are most at risk from drinking tend to be the ones that come into direct contact with alcohol, including in the mouth and neck.

Drinking alcohol increases the risk of four types of cancer in the mouth and upper digestive tract: oral, pharyngeal (throat), laryngeal (voice box) and oesophageal. The mouth, throat and oesophagus are particularly vulnerable since those tissues have some of the greatest exposure to acetaldehyde.

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According to one analysis, the risk of mouth and throat cancers increases by 13 per cent and the risk of oesophageal cancer by 26 per cent with just one drink per day. For people who have five or more drinks a day, the risk of all three cancers is roughly four times higher.

Heart and chest

Alcohol affects the cardiovascular system in a number of ways, some better understood than others. Illustration: Montse Galbany/New York Times
Alcohol affects the cardiovascular system in a number of ways, some better understood than others. Illustration: Montse Galbany/New York Times

A few decades ago, scientists thought alcohol might benefit heart health. But that perspective has changed among some experts in recent years as more research has come to light.

Alcohol’s relationship to heart attacks and strokes is more complicated. Heavy drinking (three or more drinks per day) is associated with a higher risk of both. But when it comes to light to moderate drinking (two drinks a day or less), the research is mixed. A few studies suggest a small increased risk of heart attack and stroke starting at one drink a day, but several others report that people who drink in moderation actually have a reduced risk, compared with people who don’t drink at all.

Gut

Alcohol's effects on the gut range from unpleasant to potentially deadly. Illustration: Montse Galbany/New York Times
Alcohol's effects on the gut range from unpleasant to potentially deadly. Illustration: Montse Galbany/New York Times

Like the mouth and throat, the stomach and intestines come into direct contact with alcohol and acetaldehyde, making them particularly susceptible to damage.

Tissues in the gastrointestinal tract are also prone to alcohol-related cancer. One recent study found that people who consistently averaged two or more drinks per day had a 25 per cent increased risk of developing colorectal cancer compared with people who averaged less than one weekly drink.

Liver

After alcohol is digested in the stomach and intestines, it enters the bloodstream and heads to the liver - the primary place alcohol is metabolised in the body. Illustration: Montse Galbany/New York Times
After alcohol is digested in the stomach and intestines, it enters the bloodstream and heads to the liver - the primary place alcohol is metabolised in the body. Illustration: Montse Galbany/New York Times

The liver may be the organ most vulnerable to damage from drinking, and alcohol-related liver disease is the leading cause of death from excessive drinking.

According to one estimate, 90 per cent of people who consume more than four drinks per day have fat deposits on their liver, and 30 per cent of people who regularly have three or more drinks a day will develop cirrhosis. The fat deposits, inflammation and early fibrosis can be reversed, but advanced liver cirrhosis is permanent.

Like in other parts of the body, heavy drinking also increases the risk of cancer in the liver, because of the DNA damage caused by acetaldehyde.

Drinking alcohol can have profound effects on the brain and body. Illustration: Montse Galbany/New York Times
Drinking alcohol can have profound effects on the brain and body. Illustration: Montse Galbany/New York Times

The facts are sobering, but take note: experts say that the odds of experiencing health harms from drinking are relatively low if you average one drink a day or less.

The risks go up at eight to 14 weekly drinks, but whether those heightened risks result in an illness often depends on people’s genetics and pre-existing conditions. And if you currently drink heavily, research shows that some of the damage can be reversed if you stop or cut back. – This article originally appeared in the New York Times