Even a single episode of binge drinking may have serious adverse effects, new research suggests.
A small study of 25 healthy adults showed that those who participated in a binge drinking exercise had a rapid increase in serum endotoxin and 16S rDNA, a marker for bacterial leakage from the gut. There was also a "prolonged increase in acute phase protein levels in the systemic circulation," report the investigators.
In addition, female participants had higher blood alcohol and circulating endotoxin levels than their male counterparts.
"I think the most surprising component was the gender difference that we found," principal investigator Gyongyi Szabo, MD, PhD, professor and vice chair in the Department of Medicine and associate dean of clinical and translational sciences at the University of Massachusetts Medical School in Worcester, told Medscape Medical News.
Dr. Szabo noted that the finding conforms with epidemiologic studies showing that women are more prone to develop alcoholic liver disease after a lower consumption of alcohol than men.
She added that clinicians should increase awareness in their patients, especially because the study suggests an alcohol binge is more dangerous than previously thought.
"In the past, people thought that bacterial product getting into the blood occurs in chronic alcohol consumption and not necessarily in binge drinking."
The study was published online May 14 in PLoS One.
Most Common Form of Alcohol Consumption
The National Institute on Alcohol Abuse and Alcoholism (NIAAA) defines binge drinking as that which brings blood alcohol concentration to 0.08 g/dL or higher. This corresponds to 5 or more drinks in a 2-hour period for a typical adult man and 4 or more drinks in a typical adult woman.
"Alcohol binge drinking...is the most frequent form of alcohol consumption worldwide," write the investigators.
"While the behavioral consequences of binge drinking are well characterized, little is known about its systemic effects on various organs and on immune responses," they add.
Dr. Szabo noted that the investigative team has spent many years researching the effects of alcohol on human health.
"We've found that alcohol has a lot of subtle effects on immunoresponses. And we were in interested in moving from chronic alcohol consumption to see what happens after an alcohol binge, particularly because it's such a common phenomenon in young adults," she said.
The researchers enrolled 14 female and 11 male volunteers who were between the ages of 21 and 56 years and who had no history of an alcohol use disorder. In addition, the participants were asked to refrain from any alcohol use during the 48 hours prior to the study's start.
All were then given enough alcohol to reach the 0.08 g/dL blood alcohol concentration level within an hour. The drink they were given combined vodka with orange/strawberry juice.
Serum samples were taken at baseline and every 30 minutes for up to 4 hours, as well as 24 hours later. Lipoprotein binding protein (LBP) and soluble CD14 (sCD14) levels were measured from the serum, and bacterial DNA was isolated and identified.
In addition, plasma collected from whole blood samples treated with lipopolysaccharide (LPS) was used to measure tumor necrosis factor–alpha (TNF-α), interleukin-6 (IL-6), and monocyte chemoattractant protein–1 (MCP-1).
"Increased serum LPS is thought to be a result of microbial translocation from the gut," write the investigators.
The average body mass index was 29.3 ± 1.1 for the men and 28.8 ± 1.38 for the women.
Results showed a rapid increase in blood alcohol level (BAL) in all of the participants, with a maximum level found 60 minutes after alcohol consumption.
Interestingly, higher BALs were found in the women, along with a slower decrease. These levels remained higher for women than for men even 24 hours later.
Serum endotoxin levels increased rapidly for all participants by the 30-minute mark and remained elevated for 3 hours after alcohol consumption. Women also showed higher levels of serum endotoxin immediately after alcohol intake, as well as at the 4-hour measurement mark.
Circulating endotoxin also induced rapid elevations in both LBP and sCD14 after alcohol consumption. And there was a significant increase after binge drinking in serum 16S bacterial rDNA levels at the 1-, 4-, and 24-hour measurement marks.
"The biological significance of the in vivo endotoxin elevation was underscored by increased levels of inflammatory cytokines, TNF-α and IL-6, and chemokine, MCP-1" in total blood samples, report the investigators.
In other words, they note in a release, the endotoxins "caused the body to produce immune cells involved in fever, inflammation, and tissue destruction."
"We found that a single alcohol binge can elicit an immune response, potentially impacting the health of an otherwise healthy individual," added Dr. Szabo in the same release.
However, she noted that the investigators did not assess long-term effects from binge drinking. "At least in the time period we looked at, it looked like things resolved and came back to normal levels. But further studies are needed to further investigate this issue."
George Koob, PhD, director of the NIAAA, said in a release that negative effects of chronic drinking are "well documented."
However, "this is a key study to show that a single alcohol binge can cause damaging effects such as bacterial leakage from the gut into the bloodstream," said Dr. Koob.
The NIAAA release added that "greater gut permeability and increased endotoxin levels have been linked to many of the health issues related to chronic drinking, including alcoholic liver disease."
Dr. Szabo noted that recent research has also suggested that binge drinking can increase risk for chronic alcoholism.
"Some of the mechanisms that our study revealed are now being investigated as a potential mechanism for making people addicted to alcohol," she said.
"For people who binge drink, I think our study provides some tangible evidence for something happening in their bodies," added Dr. Szabo.
"As physicians, we tell people, 'don't drink.' But it's sometimes hard to get them to follow that advice if you don't have anything to explain why. Hopefully this will help to educate the public."
The study authors report no relevant financial relationships.
Source: Deborah Brauser at Medscape Medical News