Just one night of binge drinking can damage your gut lining, study finds

A Harvard-led study shows even one episode of binge drinking can injure the small intestine, weaken the gut barrier and trigger immune responses that allow toxins to leak into the bloodstream

A heavy night of drinking may feel like a harmless indulgence, but its effects on the gut may last longer than expected.

 

A new study shows that even a single binge can damage the upper small intestine, weaken the gut barrier and allow harmful toxins to enter the bloodstream.

 

Titled Unravelling the gastrointestinal tract’s response to alcohol binges: Neutrophil recruitment, neutrophil extracellular traps, and intestinal injury, published in Alcohol: Clinical and Experimental Research, the study suggests even short bursts of heavy drinking can trigger processes linked to inflammation and liver injury.

 

The upper small intestine is the first part of the digestive tract to encounter high concentrations of alcohol. The researchers found that if this region is damaged, bacteria and toxins from the gut can slip into the bloodstream and travel straight to the liver, fuelling inflammation.

What counts as binge drinking, and how does it affect the gut?

According to the study, binge drinking means consuming a large amount of alcohol over a short period. In human terms, that is roughly four drinks for women or five for men within about two hours. In the study, researchers mimicked this pattern in mice by giving high doses of alcohol over three days to understand what happens in the gut immediately after such exposure.

 

The researchers found that binge drinking not only damaged the upper intestine, it also triggered an influx of neutrophils, immune cells usually deployed to fight infections. Here, they rushed to the gut lining even though there was no invading pathogen. Their presence matters because neutrophils can cause collateral damage when activated in the wrong place.

 

The scientists say neutrophils can release sticky, web-like structures called neutrophil extracellular traps, or NETs. These traps are meant to snare microbes, but in this case they ended up damaging the gut lining itself. The study showed that NETs weakened the intestinal barrier, making it leaky and allowing bacterial toxins, known as endotoxins, to enter the bloodstream. 

Does binge drinking really cause a ‘leaky gut’?

The study says it does. It found increased levels of endotoxin in the blood after binge drinking, a hallmark of a leaky gut. While some immune changes settled within 24 hours, the structural injury to the intestine lingered, suggesting the gut may not bounce back as quickly as assumed.

Can alcohol-related gut damage be prevented or reversed?

In the study, researchers used an enzyme called DNase to break down NETs. When NETs were dismantled, gut injury was reduced, fewer neutrophils accumulated and endotoxin levels dropped. While this does not translate directly into a treatment for humans yet, it points to possible future strategies to protect the gut from alcohol-related harm.

Should this change how we think about binge drinking?

The study shifts the spotlight to the gut as an early and vulnerable target of alcohol damage. Corresponding author Gyongyi Szabo, professor of medicine at Harvard Medical School, said in a statement that these early changes may be the first step in a cascade leading to liver injury. The gut, it seems, is not just a passive bystander. It may be where alcohol’s damage begins.