Does alcohol weaken immunity and make us more susceptible to illness?

by Christine Humphreys

Published: April 06, 2021 Last updated: November 30, 2023

How is it that some people dismiss a virus as a 'touch of the sniffles' while others are incapacitated by 'the flu'?

It's intriguing that robust individuals can be 'bed-ridden' by a cold, while others continue their daily routines seemingly unaffected by the same bug.

Undoubtedly, many factors contribute to this disparity, but emerging research suggests that one common element in our social lives may play a crucial role.

Could alcohol be the deciding factor?

Alcohol consumption impacts on immune system health, raises the risk of infection and is more likely to lead to severe illness even in otherwise healthy people.

Those with an existing medical condition may show more severe symptoms and have more adverse health outcomes.

Common symptoms of respiratory virus include a cough and fever, and infected people can pass on the infection when droplets from the mouth or nose contaminate surfaces or pass directly to another person.

That's why it's important to avoid social contact when we know we have a virus and to wash our hands often and use anti-viral hand gel whenever hand washing isn't practical.

Drinking impairs cells in key organs

Experts explain that when someone is exposed to a virus, the immune system goes into attack mode to kill the microorganisms that cause the disease.

The stronger the person’s immune system, the faster the body can clear a virus and recover.

Alcohol directly affects the balance of the immune system and makes it harder for it to put up a defence making alcohol consumption a strong risk factor.

Infectious diseases are more likely to have a long-term impact on people with health conditions such as heart, lung or respiratory diseases. This is also the case where people suffer from asthma, diabetes and liver disease.

“Alcohol has diverse adverse effects throughout the body, including on all cells of the immune system, that lead to increased risk of serious infections,” said Dr. E. Jennifer Edelman , a Yale Medicine addiction medicine specialist.

Got a cough? It may be the booze…

While most people understand the health risks of excess drinking damaging vital organs, many may not be aware of the adverse impact of regular drinking on the airways and lungs.

This is one reason why heavy drinkers often have a persistent cough and are more prone to chronic conditions of the respiratory system and are more prone to respiratory illness such a pneumonia.

Most people are aware of the link between tobacco and lung disease, but drinking regularly damages the lining of the airways and the lungs so it’s easier for the tiny virus particles to enter the body in the first place.

Experts say that once a virus enters the body, a person with a weakened immune system is much more likely to suffer more severe symptoms and develop complications.

Frequent drinking also damages gut health by destroying the microorganisms in the intestine that help maintain immunity.

When healthy gut bacteria is damaged, this leads to inflammation.

If the body can’t fight the pathogen, an infection can worsen and lead to more severe, life-threatening complications, particularly among those already battling severe diseases, and lead to worse outcomes.

Research has shown that heavy drinkers are more likely to develop lung disease such as pneumonia, tuberculosis and other pulmonary conditions.

How does the body respond to alcohol?

Even as we sip a drink, our body prioritises breaking down the toxins that enter the digestive system through the liver, so the body is less effective at warding off infection.

Even moderate alcohol intake may be a danger to sick people with an underlying condition.

Our sleep quality will also be impaired. People who don’t get enough good quality sleep are more prone to illness.

One study found that people who got less than 7 hours of sleep were nearly three times more likely to develop a cold compared with those who got 8 or more hours of sleep.

A lack of sleep can also affect how long it takes for a person to recover if they do get sick, according to the Mayo Clinic

The morning after the night before risk

It’s unclear how much alcohol it takes to impair the immune system but it is known that binge drinking can have a massive effect on the immune system.

Leading physicians say that doses of around 14 drinks per week or more than five to six drinks at a time directly suppress the immune system.

Evidence also shows that even smaller amounts of alcohol can affect the immune system so people should limit themselves to a maximum of three drinks a day on no more than four days a week.

A brief but interesting experiment by the BBC showed how immediate the impact of alcohol can be on immune function.

One reporter took a blood test prior to drinking alcohol and repeated the test after consuming around three glasses of Prosecco.

A blood test the following morning showed that immune cells in the reporter’s blood had diminished.

The reporter stated that the drink had substantially reduced the number of lymphocytes – the specialist cells in the body that help fight infection.

Most were down by 20 to 30% but some lymphocyte T cells that form an essential part of the immune system had dropped by as much as half.

Doctors monitoring the experiment confirmed that, at this diminished rate of immunity, a person coming into contact with an infected passenger on a bus or train would have much less protection against infection.

For good health, drinking less is best

Only a minority of virus patients end up in hospital with life-threatening symptoms. Older people are much more likely to develop more serious symptoms as their immune systems tend to be less efficient at clearing viral infections.

Patients who develop serious or fatal illness are more likely to have at least one major underlying health condition, such as diabetes, hypertension, obesity, cardiovascular diseases, asthma, kidney disease or chronic obstructive pulmonary disorder. Diabetes and obesity are also associated with a weaker resistance to infections

Patients with these disorders often use immune-suppressing drugs, which reduce immunity to respiratory infections.

Having an unusually weakened immune system, for example due to cancer treatments, organ transplants, or other conditions requiring patients to take immune-suppressing drugs, is another factor that may greatly increase the susceptibility to serious infection.

Some people who seem perfectly healthy and are not considered immune-deficient may nevertheless have inherited immune system features that leave them more vulnerable than average to certain viral infections.

So mum's 'little sherry' in the afternoon or dad's pint with his chums may not be as harmless as we'd like to think and for all of us wanting to avoid that a nasty cold or worse, drinking less is best.

About The Author

Christine Humphreys

Chris Humphreys is the co-founder of The Alcohol-Free Shop and AlcoholFree.com. She was a journalist for more years than she cares to remember. Ex-wife of an alcoholic, enthusiastic amateur musician and a passionate dog lover.