What drinking alcohol does to your body

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Grog, liquor, booze, coldie, brew, moonshine, nip, vino – they’re all nicknames for a widely used drug – alcohol. So what does alcohol do to your body?

Many Kiwis drink alcohol in the form of beer, wine or liquor. They drink alcohol to relax, celebrate and socialize. Alcohol affects people in different ways, and people have different relationships with alcohol. Many can enjoy a glass of wine with food, or drink moderate amounts of alcohol in social settings without any problems. Having one drink per day for women and two drinks per day for men is defined as moderate drinking.

New Zealanders appear to be drinking less alcohol now according to the Ministry of Health. The Ministry found that proportion of New Zealanders aged 15 years or more who drank alcohol in the past year dropped from 84% in 2006/07 to 80% in 2011/12 (Ministry of Health, 2013). And the proportion of 15 to 17-year-olds dropped from 75% in 2006/07 to 59% in 2011/12.

So it would appear that the message is getting through that drinking too much or too often is bad for you. But wait a minute. Don’t jump to conclusions so quickly, the medicos tell us. Health experts certainly welcomed the reduction in consumption, even so, one in five (19%) New Zealanders aged 15 years or more who drank alcohol in the past year has a potentially hazardous drinking pattern and between 600 and 800 people in New Zealand have been estimated to die each year from alcohol related causes.

Sobering stats indeed. But exactly how does alcohol negatively affect the body? Let’s break it down into standard nips.

What is alcohol?

Alcohol, or ethyl alcohol, is a depressant that affects the central nervous system, slowing down messages from the brain to the body. In everyday use, alcohol usually refers to drinks such as beer, wine, or spirits. It is commonly considered a drug, even though it is used by many people who do not consider themselves drug users.

Effects of alcohol

Because alcohol is a depressant, it slows the function of the central nervous system and alters a person’s perception, emotion, movement, vision and hearing.  Small amounts of alcohol can make a person feel more relaxed or less anxious. Larger amounts lead to intoxication, or drunkenness, by causing greater changes in the brain.  It is these intoxicating and psychoactive effects that lead to accidents, injuries, diseases, and disruptions in family life.

Alcohol affects everyone differently, based on:

  • Size, weight and health
  • Whether the person is used to taking it
  • Whether other drugs are taken around the same time
  • The amount drunk
  • The strength of the drink

If a small amount of alcohol is consumed, you may experience:

  • Feeling relaxed
  • Trouble concentrating
  • Slower reflexes
  • Increased confidence
  • Feeling happier or sadder, depending on your mood

If a lot of alcohol is consumed, you may also experience:

  • Confusion
  • Blurred vision
  • Clumsiness
  • Memory loss
  • Nausea, vomiting
  • Passing out
  • Coma
  • Death

But there’s a safe alcohol limit, isn’t there?

Alcohol is a drug and, at the risk of being labelled a wowser, there is no safe level of drug use. The use of any drug, legal or illegal, always carries some risk. Due to the radically different ways that alcohol can affect people, there can be no one-size-fits-all safety rule for everyone. People choosing to drink must realise that there will always be some risk to their health and social well-being. However, there are ways to minimise the risks of alcohol-related harms.

Government guidelines recommend healthy men drink no more than three standard drinks (no more than 15 per week) and women drink no more than two standard drinks (no more than 10 per week) on any day to reduce the risk of harm from alcohol-related disease or injury over a lifetime. As well, all Kiwis are recommended to have at least two alcohol-free days per week.

Drinking no more than four standard drinks on a single occasion reduces the risk of alcohol-related injury arising from that occasion. More details on the definition of standard drinks and alcohol content can be found at http://alcohol.org.nz/help-advice/advice-on-alcohol/low-risk-alcohol-drinking-advice

Why do we get hangovers?

The most immediate and unpleasant effect from overdoing alcohol consumption is the dreaded hangover next morning.  We’ve all been there – well, the majority of drinkers anyway – and despite their often horrendous nature, hangovers don’t seem to put us off getting boozy. But why do we actually get them, what is it about drinking too much alcohol that makes you feel like you absolutely must devour 6 kebabs at midnight, then want to crawl into a hole and cry the next morning?

We’re all familiar with the delightful symptoms of a hangover (headache, trembling, nausea, fatigue, dehydration, diarrhea, etc), and for many years, dehydration was blamed as the primary cause for hangovers. Alcohol is a diuretic, meaning it makes you lose water. This is likely to result in a whopping headache. But there are other evil factors at work here. As your body attempts to restore fluid levels, your blood vessels narrow, restricting the flow of blood and oxygen to the brain, which then tries to compensate by dilating its blood vessels, which can cause swelling. Although the brain itself can’t feel pain, the discomfort may result from pain receptors in the lining that surrounds our brain.

So what makes our stomach churn the morning after? Alcohol actually irritates your stomach and intestine, causing inflammation of the stomach lining and delayed emptying of the stomach contents. It also causes us to produce more gastric acid alongside increasing the levels of pancreatic and intestinal secretions. Both of these can lead to that delightful nausea we often experience, or even cause us to throw up.

Another candidate for the origin of a hangover is a toxic compound called acetaldehyde, which builds up as a byproduct as our body processes alcohol. It’s thought to be up to 30 times more toxic than alcohol itself, and has been found to produce hangover-like symptoms in studies.

One final intriguing hypothesis is that hangovers are actually the result of our immune systems – namely, high levels of cytokines, which are substances secreted by immune cells that are involved in inflammation and cellular communication. Normally, these help us fight off infections, but if you inject large enough doses into healthy people, they start to experience hangover symptoms like nausea, headache and fatigue. Furthermore, some lines of evidence have hinted that abnormally high levels of cytokines could disrupt memory formation in the brain, which could help explain why many of us wake up totally oblivious of our late night shenanigans.

Another contributing factor is your choice of tipple. Different alcoholic beverages have varying amounts of compounds called congeners, which are sometimes produced during the fermentation process or added in afterwards. Some studies have found that beverages high in congeners, like brandy and red wine, are much more likely to result in a hangover than drinks with few or no congeners, like gin and vodka. However, a more recent study found that congener content didn’t actually cause differing effects on sleep, reaction time or memory the next day, despite participants reporting feeling worse on high-congener drinks.

Whatever the cause, hangovers are nothing to look forward to!

Let’s get down to the serious stuff

We all know that alcoholism is linked to major health problems like liver disease but researchers tell us alcohol does all kinds of things in the body and is linked to no less than 60 diseases. The reason alcohol in general gets such a bad rap is that it is addictive and, for certain people, relatively easy to slide from social drinking into heavy or binge drinking, dependency, alcohol abuse and alcoholism.

People who abuse alcohol may not have a physical dependence on alcohol but they are more focused on intoxication than on safely enjoying alcoholic beverages. Abuse can affect relationships and lead to failure to meet obligations at home, work, or school. Long-term alcohol abuse may lead to alcoholism. This is a serious medical condition. People with alcoholism can find drinking moderately or stopping drinking very difficult. They may struggle to live their lives normally. And they may face serious health consequences.

Here’s a list of bedtime reading on some well-known effects. But before you read this and swear off alcohol for life, remember the word ‘moderation’. Alcohol consumed in moderation and not necessarily on a daily basis, can be enjoyable and relaxing without doing you harm. That is, of course, if you don’t already have liver disease or if you plan to have a child at any time in the near future.

Alcohol and the Central Nervous System

From the very first time you drink alcohol, you’ll probably notice its effects on your central nervous system. Alcohol is a depressant, which slows down your voluntary and involuntary actions. When you drink, you may have impaired motor coordination, slower reaction times, loss of memory while drinking (blackouts), and difficulty processing information.  Alcohol travels through the body easily. It can quickly reach many parts of your body, including your brain and other parts of your central nervous system. That can make it harder to talk, causing slurred speech, the tell-tale sign that someone has had too much to drink. It can also affect coordination, interfering with balance and the ability to walk. Drink too much and your ability to think clearly is in trouble, as are your impulse control and ability to form memories. Over time, you may notice that alcohol has a permanent effect on your cognitive abilities. According to many studies, heavy drinkers show a lower ability to think abstractly than non-drinkers, even when they’re sober.

In the longer term, drinking can actually shrink the frontal lobes of your brain. Acute alcoholic withdrawal can lead to seizures and delirium. And severe alcoholism can progress to permanent brain damage, causing dementia. Damage to your nervous system can result in pain, numbness, or abnormal sensations in your feet and hands. Alcoholism can cause a thiamine (vitamin B1) deficiency, which can result in involuntary rapid eye movements, weakness, or paralysis of the eye muscles.

Alcohol and your Liver

Out of all the organs that are damaged by heavy alcohol use, the liver often suffers most, typically through alcoholic hepatitis, which involves swelling, pain and inflammation of the liver. This affects up to 50% of heavy drinkers, and cirrhosis (irreversible scarring of the liver) affects between 15 and 30% of people who abuse alcohol.

What’s so important about your liver? There are many reasons to appreciate and protect this hard-working organ. Your liver plays vital roles in digestion, protein production, detoxification and blood circulation, including:

  • Eliminating toxins from your body
  • Building proteins and making cholesterol
  • Processing sugars and fats
  • Storing vitamins and minerals
  • Regulating blood clotting and blood fluid content

Your liver also metabolizes most of the alcohol you drink, and the more alcohol you consume, the more damage your liver incurs. The damage to your liver is progressive and cumulative, meaning that you may not see the results right away. However, over time, heavy drinkers can experience liver-related problems like:

  • Weakness
  • Weight loss
  • Hardening and swelling of the liver
  • Nausea and vomiting
  • Malfunctions of the brain
  • Kidney disease

Sexuality and drinking

When it comes to your sexuality, alcohol can be dangerously deceptive. Because alcohol releases inhibitions and relaxes your judgment, you may feel more sexually attractive and have a higher sex drive when you’re drinking. But in reality, heavy alcohol use can lead to sexual dysfunction and impotence. Both men and women can experience problems with sexual response, which are often made worse by the emotional disturbances, depression and fatigue that alcohol can cause. Or in the words of Shakespeare, it provokes the desire, but it takes away the performance.

When your judgment is blurred by alcohol, you may be more likely to have unsafe sex. Sexually transmitted diseases like HIV, hepatitis, herpes, gonorrhea, chlamydia, syphilis and the human papillomavirus (HPV) can have severe, life-changing consequences.

Alcohol and Reproductive Problems

Apart from heavy drinking altering hormone production excessive drinking can reportedly increase a woman’s risk of miscarriage, premature delivery and stillbirth. Alcohol has a huge effect on fetal development. A range of problems, called fetal alcohol spectrum disorders (FASD), can occur. FASD symptoms, which include a baby’s physical abnormalities, learning difficulties, and emotional problems, can, and often do, last a lifetime. For women, the risk of breast cancer rises with alcohol use.

Some more health issues…


Heavy drinking can apparently cause the number of oxygen-carrying red blood cells to be abnormally low. This condition, known as anemia, can trigger a host of symptoms, including fatigue, shortness of breath, and lightheadedness.


Habitual drinking has been linked to an increased the risk of cancer, believed to come about when the body converts alcohol into acetaldehyde, a potent carcinogen. Cancer sites linked to alcohol use include the mouth, pharynx (throat), larynx (voice box), esophagus, liver, breast, and colorectal region. Cancer risk rises even higher in heavy drinkers who also use tobacco.

Cardiovascular disease

Heavy drinking, especially bingeing, makes platelets more likely to clump together into blood clots, which can lead to heart attack or stroke. In a landmark study, Harvard researchers found that binge drinking doubled the risk of death among people who initially survived a heart attack.

Heavy drinking can also cause cardiomyopathy, a potentially deadly condition in which the heart muscle weakens and eventually fails, as well as heart rhythm abnormalities such as atrial and ventricular fibrillation. Atrial fibrillation, in which the heart’s upper chambers (atria) twitch chaotically rather than constrict rhythmically, can cause blood clots that can trigger a stroke. Ventricular fibrillation causes chaotic twitching in the heart’s main pumping chambers (ventricles). It causes rapid loss of consciousness and, in the absence of immediate treatment, sudden death.


Alcohol is toxic to liver cells, and heavy drinkers may develop cirrhosis, a sometimes-lethal condition in which the liver is so heavily scarred that it is unable to function. But it’s hard to predict which drinkers will develop cirrhosis. Some people who drink huge amounts never get cirrhosis, and some who don’t drink very much get it. For some unknown reason, women seem to be especially vulnerable.


As people age their brains shrink, on average, at a rate of about 1.9 percent per decade. That’s considered normal. But heavy drinking can speed the shrinkage of certain key regions in the brain, resulting in memory loss and other symptoms of dementia.  Heavy drinking can also lead to subtle but potentially debilitating deficits in the ability to plan, make judgments, solve problems, and perform other aspects of “executive function,” which are the higher-order abilities that allow us to maximize our function as human beings. In addition to the “nonspecific” dementia that stems from brain atrophy, heavy drinking can cause nutritional deficiencies so severe that they trigger other forms of dementia.


It’s long been known that heavy drinking often goes hand in hand with depression, but there has been debate about which came first — the drinking or the depression. One theory is that depressed people turned to alcohol in an attempt to “self-medicate” to ease their emotional pain. But a large New Zealand study showed that it was probably the other way around — that is, heavy drinking led to depression. Research has also shown that depression improves when heavy drinkers go on the wagon.


Heavy drinking can cause epilepsy and can trigger seizures even in people who don’t have epilepsy. It can also interfere with the action of the medications used to treat convulsions.


A painful condition, gout is caused by the formation of uric acid crystals in the joints. Although some cases are largely hereditary, alcohol and other dietary factors seem to play a role. Alcohol also seems to aggravate existing cases of gout.

High blood pressure

Alcohol can disrupt the sympathetic nervous system, which, among other things, controls the constriction and dilation of blood vessels in response to stress, temperature, exertion, etc. Heavy drinking — and bingeing, in particular — can cause blood pressure to rise. Over time, this effect can become chronic. High blood pressure can lead to many other health problems, including kidney disease, heart disease and stroke.

Infectious disease

Heavy drinking suppresses the immune system, which can prong a toehold for infections, including tuberculosis, pneumonia, HIV/AIDS, and other sexually transmitted diseases (including some that cause infertility).

Nerve damage

Heavy drinking can cause a form of nerve damage known as alcoholic neuropathy, which can produce a painful pins-and-needles feeling or numbness in the extremities as well as muscle weakness, incontinence, constipation, erectile dysfunction, and other problems. Alcoholic neuropathy may arise because alcohol is toxic to nerve cells, or because nutritional deficiencies attributable to heavy drinking compromise nerve function.


In addition to causing stomach irritation (gastritis), drinking can inflame the pancreas. Chronic pancreatitis interferes with the digestive process, causing severe abdominal pain and persistent diarrhea –and it’s not fixable. Some cases of chronic pancreatitis are triggered by gallstones, but up to 60% stem from alcohol consumption.

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