What does alcohol do to your immune system?
Chronic excessive alcohol use weakens your immune system on multiple fronts simultaneously and increases the risk of serious infections. Light to moderate drinking appears less harmful, but offers no demonstrable benefit for your immune system.
Chronic excessive alcohol use damages several layers of your immune system at the same time. The cells that clear out pathogens, such as neutrophils and macrophages, function noticeably less well. At the same time, your T-cells and B-cells are also affected: the cells responsible for targeted, long-lasting protection. As a result, infections are not only picked up more easily, but also fought off less effectively, and vaccines may not work as well.
Alcohol also throws the balance of signalling substances in your body into disarray. Inflammation-promoting substances rise, while protective substances decline. The result is too much inflammation in some places and too little immune defence in others.
The consequences are concretely measurable in terms of disease risk. People who drink heavily on a chronic basis are demonstrably more likely to develop serious bacterial infections such as pneumonia and tuberculosis, and also recover from them more poorly. A heightened risk has also been described for viral infections, including hepatitis and HIV, although the precise underlying mechanism has not yet been fully clarified. The lungs are particularly vulnerable: the mucous membranes and local immune defences function less well, making it easier for harmful bacteria to take hold.
Animal studies show that alcohol consumed before a serious traumatic injury makes the body's immune reaction more dangerous than trauma or alcohol alone: death rates following infection rose sharply. Whether this works in exactly the same way in people has not yet been fully investigated, but it is a relevant safety concern in emergency situations.
A more nuanced picture exists for light to moderate drinking. Some studies suggest that moderate consumption, especially of drinks rich in plant compounds such as wine, may be less harmful to the immune system than heavy drinking, and may even be associated with slightly less inflammation. However, this evidence is limited and the mechanisms are poorly understood. It does not justify a recommendation to drink alcohol for the benefit of your immune system.
This answer draws on several reviews that bring together existing research. The evidence on chronic excessive drinking is broadly supported and consistent: multiple independent reviews reach the same conclusions about immune cell dysfunction and infection risk. The section on moderate drinking rests on only two reviews, and the evidence within them is mixed and limited. The section on alcohol and trauma is based primarily on animal studies from a single review. The researchers themselves emphasise that drinking pattern, sex, type of drink and other factors make comparison difficult.
Does too little sleep weaken your immune system?
Yes, too little sleep demonstrably weakens your immune system and increases the risk of infections and chronic inflammatory conditions. Seven to nine hours of sleep is the most commonly cited guideline, and vaccinations also work better when you are well rested.
Does your immune system really weaken as you get older?
Your immune system demonstrably weakens with age, but vaccinations remain worthwhile and a good diet can limit further decline.
What does regular sauna use do to your immune system?
Regular sauna use produces measurable changes in your immune system, but whether it actually makes you get sick less often has not yet been proven. The signals are positive enough to regard the sauna as part of a healthy lifestyle, but specific health claims are premature.
Does creatine do anything to your immune system?
Creatine influences immune cells via a specific switch, but whether the outcome is favourable or unfavourable depends strongly on the situation. For boosting immunity or preventing infections, there is too little evidence in humans to recommend it.
Can air pollution weaken your immune system?
Air pollution disrupts your immune system in several ways at once: a greater chance of allergic reactions, less resistance to viruses. Limit your exposure as much as possible, especially during pregnancy.
What does sleep deprivation do to your immune system?
Sleep deprivation demonstrably weakens your immune system: sleeping fewer than six hours significantly increases your infection risk and impairs your immune cells. Make sure to structurally get seven hours or more, because a single recovery night is not enough to repair the damage.