The immune system has a vital role: It protects your body from harmful substances (pathogens) and cell changes that could make you ill.
It is made up of various organs, cells and proteins.
If pathogens pass the non-specific first line of the body’s defence mechanisms, they will cause an infection. However, the body has a second line of defence to stop or minimise this infection - the immune system, which mainly consists of two types of white blood cell called phagocytes and lymphocytes.
Phagocytes are attracted to pathogens in the blood and bind to them. The phagocyte’s membrane surrounds the pathogen and engulfs it. Enzymes found inside the cell then break down the pathogen in order to destroy it. As phagocytes do this to all pathogens that they encounter, they are called non-specific.
Lymphocytes are another type of white blood cell. They recognise proteins on the surface of pathogens called antigens. Lymphocytes detect that these are foreign, ie not naturally occurring within the body, and produce antibodies. This can take a few days, during which time you may feel ill. The antibodies cause pathogens to stick together and make it easier for phagocytes to engulf them.
Some pathogens produce toxins which make you feel ill. Lymphocytes can also produce antitoxins to neutralise these toxins. Both the antibodies and antitoxins are highly specific to the antigen or the pathogen, therefore the lymphocytes that produce them are called specific.
If your body encounters a particular antigen, your lymphocytes might recognise it. If they do, they clone themselves in order to make enough antibodies to destroy the pathogen. Memory cells are also created which remain in your bloodstream and produce a quick response if the antigen is encountered again. You are then said to be immune.
The best immunity comes from having fought off a disease. However, in some cases such as a serious disease that could prove fatal on first infection, this is not an option. Instead vaccination is used.
However, for a wide variety of reasons, the immune system can become weak and fail to protect you against infection.
The effect of alcohol on the immune system
Healthy habits, such as being active, eating a balanced diet, and getting enough sleep, can keep your immune system strong. But unhealthy factors, like stress, smoking, or drinking alcohol, can be taxing for your immune system and make it harder for it to fight off infection.
Drinking gives your body work to do that keeps it from other processes. Once you take a drink, your body makes metabolising it a priority — above processing anything else. Unlike proteins, carbohydrates and fats, your body doesn’t have a way to store alcohol, so it has to move to the front of the metabolising line. This is why it affects your liver, as it’s your liver’s job to detoxify and remove alcohol from your blood.
What you need to know about how alcohol affects your immune system.
One of the least appreciated medical complications of alcohol intake is its effect on the immune system. Excess alcohol consumption may lead to immune deficiency, causing increased susceptibility to certain diseases. Alcohol alters the make up of your gut microbiome— home to trillions of micro organisms performing several crucial roles for your health — and affects those micro organisms' ability to support your immune system. Drinking alcohol may also damage the immune cells that line the intestines and serve as the first line of defence against bacteria and viruses. By damaging those cells in your intestines, it can make it easier for pathogens to cross into your bloodstream.
Not just about chronic alcohol consumption
Alcohol consumption does not have to be chronic to have negative health consequences. In fact, research shows that acute binge drinking also significantly impacts the effectiveness of the immune system.
Drinking alcohol in large quantities even just for a short period of time — binge drinking — can reduce infection-fighting white blood cells known as monocytes in the hours after peak intoxication, essentially weakening your immune system by up to 50%.
Clinicians have long observed an association between excessive alcohol consumption and adverse immune-related health effects such as susceptibility to pneumonia. In recent decades, this association has been expanded to a greater likelihood of acute respiratory stress syndromes (ARDS).
Alcohol disrupts ciliary function in the upper airways, impairs the function of immune cells (i.e., alveolar macrophages and neutrophils), and weakens the barrier function of the epithelia in the lower airways. Often, the alcohol-provoked lung damage goes undetected until a second insult, such as a respiratory infection, leads to more severe lung diseases than those seen in nondrinkers.
How much alcohol is OK?
The widely accepted guidelines state that a moderate amount of drinking — one drink per day for women, and two drinks per day for men is generally safe for people in good health and unlikely to have a negative effect on their immune systems.