<\/p>\n
But just like a muscle, the immune system can become weak and fail to protect you against infection as well. 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. When someone is exposed to a virus, the body mounts an immune response to attack and kill the foreign pathogen. Alcohol has been flying off the shelves as people try to combat boredom during lockdown, with some reports estimating that alcoholic beverage sales surged by 55 percent toward the end of March.<\/p>\n<\/p>\n
For example, one study found that women who consumed 330 mL of beer for 30 days exhibited a significant increase in leukocytes, mature CD3+ T-cells, neutrophils, and basophils. In contrast, men who consumed a similarly moderate amount of beer for the same period exhibited a significant increase in basophils alone. The gastrointestinal (GI) system is typically the first point of contact for alcohol as it passes through the body and is where alcohol is absorbed into the bloodstream. One of the most significant immediate effects of alcohol is that it affects the structure and integrity of the GI tract. For example, alcohol alters the numbers and relative abundances of microbes in the gut microbiome (see the article by Engen and colleagues), an extensive community of microorganisms in the intestine that aid in normal gut function. Alcohol disrupts communication between these organisms and the intestinal immune system.<\/p>\n<\/p>\n
Alcohol intake kills this bacteria, hindering the body\u2019s ability to clear pathogens. Without healthy gut bacteria, viruses and infections can worsen and develop into more severe complications. Alcohol also damages T cells, neutrophils, and epithelial cells, which disrupts the gut barrier\u2019s function. Alcohol also activates an enzyme acting at the thymocyte membrane called adenylate cyclase, which increases the intracellular concentration of cyclic AMP (Atkinson et al. 1977). CAMP has multiple regulatory functions in the cell, and increased cAMP levels can stimulate DNA fragmentation, leading to thymocyte apoptosis (McConkey et al. 1990). Finally, exposure to ethanol concentrations of 0.4 to 2 percent had a more profound effect on apoptosis of cultured thymocytes than on mature T cells (Slukvin and Jerrells 1995).<\/p>\n<\/p>\n
<\/p>\n
The impact of alcohol on NK cells, which are the first responders against tumor-forming cells, has been investigated in mouse models. Those studies showed decreased cytolytic activity of NK cells in C57BL\/6 mice consuming 20 percent ethanol for 4 weeks; however, no differences existed in the metastasis of B16-BL6 melanoma cells in alcohol-consuming and control animals (Meadows et al. 1993). The presence of ethanol in an in vitro culture of spleen cells also suppressed NK cell cytotoxic activity against MADB106 tumor cells (Yirmiya et al. 1992). The mechanisms by which moderate alcohol consumption might exert these beneficial effects are only beginning to emerge. In a study examining the impact of moderate alcohol consumption on gene-expression patterns in blood cells (Joosten et al. 2012), young men consumed either 100 mL vodka with 200 mL orange juice or only orange juice daily during dinner for 4 weeks.<\/p>\n<\/p>\n
Other studies were conducted using a precursor cell type called oligoclonal-neonatal-progenitor (ONP) cells, which in vitro can differentiate either into B lymphocytes or into other white and red blood cells (i.e., myeloid cells), depending on the cytokines to which they are exposed. Similarly, ONP cells isolated from newborn mice and cultured in vitro in the presence of 100 mM ethanol for 12 days failed to respond to IL-7 and commit to the B lineage, suggesting intrinsic defects (Wang et al. 2011). Additional investigations demonstrated that alcohol affects ONP cell differentiation into B lineage at a late stage by down-regulating the expression of several transcription factors (e.g., EBF and PAX5) and cytokine receptors, such as the IL-7 receptor (IL-7Ra) (Wang et al. 2009). In addition to pneumonia, alcohol consumption has been linked to pulmonary diseases, including tuberculosis, respiratory syncytial virus, and 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 (see the article by Simet and Sisson). 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.<\/p>\n<\/p>\n
Moreover, some people shouldn’t drink at all, according to the Dietary Guidelines. This includes people who are pregnant, have alcohol abuse disorder, or are taking medications that interact with alcohol. “Drinking alcohol in large quantities even just for a short period of time \u2014 like binge drinking \u2014 can be bad for your health and your immune system,” says Favini.<\/p>\n<\/p>\n