Alcohol is a very common chemical in today’s society and has been around for thousands of years. Most people are familiar with circumstances where a friend or family member has developed a cold or other infection after a night of heavy drinking. There is considerable evidence now available showing that alcohol has a strong ability to weaken our immune system.

Dr. Gary A. Roselle, professor at the University of Cincinnati Medical Center, Division of Infectious Diseases, summarized the effects of alcohol on the immune system in a 1992 article published in in Alcohol, Health & Research World. Below are highlights from his report.

Alcohol Disrupts Interleukin II

When your body is exposed to a virus, bacteria or other foreign substance, it responds by greatly increasing the number of T-cells (remember, T-cells command the primary assault against the invader). Alcohol was shown in inhibit the normal T-cell proliferation that occurs after exposure to the foreign substance. There was no reduction in the amount of interleukin-2 which normally stimulates this T-cell proliferation. The researchers believe that alcohol somehow interferes with the T-cells ability to use interleukin-2, thereby resulting in the inability to multiply properly
(Kaplan 1986)

Cancer Fighting of Killer Cells Weakened by Alcohol
Laboratory mice ingesting alcohol for one or two weeks showed a decrease in the ability of their Natural Killer cells to kill tumor cells.
(Meadows and co-workers 1989)

Pneumonia Risk Higher for Alcoholics
Macrophages play the primary role in alerting T-cells that a virus or other invader is present. Macrophages also play an important role in eliminating bacteria from the lungs. Acute alcohol administration slowed the killing of the bacteria staphylococcus and klebsiella pneumonia, two bacteria that commonly cause pneumonia and other infections in alcoholics.
(Nelson 1990)

T-Cell Cytokines Reduced
Cytokines are the chemical messengers produced by white blood cells and body cells that enhance immune system function. One such cytokine is called MIF (Migration Inhibition Factor). MIF is produced by T-cells and is believed to be the signal that encourages macrophages to accumulate at the site of infection. Even an alcohol exposure for as little as eight days resulted in lower production of MIF. Researchers stated that decreases in the MIF activity may result in fewer macrophages and neutrophils at the infection site, thereby decreasing the ability to eradicate infection.
(Roselle and Dehne 1989)

T and B-Cells Reduced in Number
Decreases were found in the number of lymphocytes (T-cells and B-cells) in alcoholic humans and lab animals who consumed alcohol for several weeks. Their lymphocytes also responded "abnormally to mitogens," (mitogens are foreign substances). This suggests harmful effects on their ability to react to infection.
(Study date 1988 & 1990)

Antibody Production Lowered
Alcohol has been shown to decrease antibody production (antibodies can bind onto foreign invaders, thereby rendering them unable to harm the body and making them more visible to other white blood cells for removal). The scientists believe this reduction in antibody production occurs because alcohol inhibits the T-cells ability to make compounds which stimulate B-cells to produce antibodies.
(Aldo-Benson 1986 and Medenhall 1988)

Malnutrition and other causes have often been cited for the alcoholics increased risk of infection, however, the documentation just presented demonstrates that alcohol itself can seriously weaken many different parts of the immune system.