The National Institute on Alcohol Abuse and Alcoholism (NIAAA) defines binge drinking as “a pattern of drinking that brings blood alcohol concentration (BAC) levels to 0.08 g/dL [the legal limit for driving]. This typically occurs after 4 drinks for women and 5 drinks for men – in about 2 hours.”
Binge drinking has been linked to car accidents, falls, burns, gunshot wounds, domestic violence, depression and other harmful effects. Past studies also linked it to impaired wound healing, increased blood loss and a higher incidence of hospital infection. This pattern of alcohol consumption is most prevalent in people aged 18 to 34.
While most drinkers understand the behavioural pitfalls associated with heavy drinking, “there is less awareness of alcohol’s harmful effects in other areas, such as the immune system,” said Elizabeth Kovacs, PhD and co-author of a new study, carried out in the University of Maryland and recently published online ahead of print in the peer-reviewed journal Alcohol.
The research team, led by Majid Afshar from Loyola University Chicago Stritch School of Medicine, asked 15 study participants (8 women and 7 men), with a median age of 27, to drink either four or five vodka-and-seltzer cocktails to meet or exceed the definition of binge drinking. A single 1.5 ounce shot of vodka contains the same amount of alcohol as a 5 ounce glass of wine or a 12 ounce can of beer.
Twenty minutes after peak intoxication, a blood sample was taken. To the researchers’ surprise, it showed that their subjects’ immune systems became more rather than less active – there were higher levels of leukocytes, monocytes and natural killer cells which comprise the core of a healthy immune system. There was also an increase in cytokines – proteins responsible for signalling the immune system to ramp up.
When blood tests were administered two and five hours later, researchers saw a reverse pattern emerge: lower levels of circulating monocytes and natural killer cells, and higher levels of proteins that “tell” the immune system to slow down.
Director of the NIAAA George Koob argues that the study proves that even one night of heavy drinking can carry serious consequences: “While it is well known that excessive alcohol use can lead to traumatic injry and the behavioural and physiological pathology associated with addition, studies like this help us understand that even a single binge drinking episode can have detrimental effects on our immune system.”
Dr. Afshar is planning to conduct a follow-up study on burn unit patients. He wants to compare those who had alcohol in their blood when they arrived to those who hadn’t, and measure their immune activity. This would help him determine their outcomes in terms of lung injury, organ failure and death.
Some reviewers have pointed out that the small sample size of this study makes its findings promising, but preliminary.