Does Alcohol Weaken the Immune System? Yes, If You Drink Too Much

That dual action predisposes heavy drinkers both to increased infection and to chronic inflammation. These articles detail how alcohol affects the immune system and how researchers are harnessing this knowledge to help prevent and treat alcohol-related harm. Alcohol alters the makeup of your gut microbiome — home to trillions of microorganisms performing several does alcohol weaken your immune system crucial roles for your health — and affects those microorganisms’ ability to support your immune system. It seems that drinking alcohol may also damage the immune cells that line the intestines and serve as the first line of defense against bacteria and viruses. Alcohol also causes damage to the cells in the outside layer of your stomach and intestines.

Over time, this can cause irreversible damage and scarring of liver tissue, called cirrhosis. If left untreated, advanced cirrhosis can develop into liver failure, a life-threatening condition. Dipak Sarkar, an expert on alcohol metabolism and immunity, and professor at Rutgers University, tells Inverse that he advises skipping alcohol altogether during the Covid-19 pandemic. This is because studies suggest that heavy drinking — defined as over 8 drinks per week for women and 15 per week for men — can disrupt key immune pathways, make people more susceptible to infection, and weaken the immune system. Acetaldehyde is the toxic byproduct that contributes to tissue damage, alcohol dependence, and addiction (Zakhari 2006). It can also bind to other proteins to form adducts, such as malondialdehyde (MDA) and MDA-acetaldehyde (MAA), which play a key role in the development of liver injury and stimulate antibody responses that further promote liver inflammation and fibrosis (Tuma and Casey 2003).

Alcohol and the Immune System

Alcohol also influences the functions of the lymphoid tissue and alter the activation, secretion, and functions of crucial immune cells called lymphocytes. An army of antibodies — Another subsystem of the immune system is called adaptive immunity. This is when the body produces an army of antibodies specific to the incoming threat. This generates “immune memory,” which ensures that the next time the body faces the same invader, the immune system is better equipped to take it down. Before you decide whether to pour a glass, it’s worth understanding how alcohol influences the immune system — as well as taking the time to reflect on your own relationship with alcohol. Alcohol does affect your ability to stay healthy, but that’s also dependent on how much you’re drinking.

This increased susceptibility has been recapitulated in rodent models of chronic alcohol abuse. For instance, increased morbidity and mortality, pulmonary virus titers, and decreased pulmonary influenza-specific CD8 T cell responses were reported in female mice infected with influenza that consumed 20% (w/v) ethanol in their drinking water for 4–8 weeks (Meyerholz, Edsen-Moore et al. 2008). Likewise, higher pathogen burden and decreased CD8 T cell immunity was observed in female mice administered ethanol at 15% (w/v) for 5 days and challenged with Listeria monocytogenes (Gurung, Young et al. 2009).

Effects of alcohol on adaptive immunity

The dendritic cell (DC), which plays a critical role in T cell activation and initiation of adaptive immune responses, is another innate immune cell affected by ethanol. DCs uptake antigens in peripheral tissues which leads to their maturation, and then travel to draining lymph nodes where they present them to T cells (Janeway 2008). Similarly, consumption of 10% (w/v) ethanol in tap water ad libitum for 2 days in mice resulted in decreased bone marrow DC generation, decreased expression of CD80 and CD86, impaired induction of T cell proliferation, and a decrease in IL-12 production (Lau, Abe et al. 2006). In addition, production of IL-10 in response to TLR2/6 stimulation was increased (Pruett, Zheng et al. 2004). This same treatment also inhibited the in vitro production of IL-6 and IL-12 by peritoneal macrophages harvested 2 hours following injection of LPS (Pruett, Fan et al. 2005).