Even a single episode of binge drinking can weaken the gut’s protective lining and trigger inflammation, increasing the risk of long-term gut and liver damage, according to a study by researchers at Harvard Medical School.
Binge drinking — defined as consuming about four drinks for women or five for men within roughly two hours — was found to reduce the gut’s ability to prevent bacteria and toxins from entering the bloodstream, a condition commonly referred to as “leaky gut.”
The findings were published in the journal Alcohol: Clinical and Experimental Research.
“We know that excessive drinking can disrupt the gut and expose the liver to harmful bacterial products, but surprisingly little was known about how the upper intestine responds in the earliest stages,” said Gyongyi Szabo, professor of medicine at Harvard Medical School and the study’s corresponding author. “Our study shows that even short bouts of binge drinking can trigger inflammation and weaken the gut barrier.”
The research team from Harvard Medical School and Beth Israel Deaconess Medical Center investigated how short, high-dose alcohol exposure affects different parts of the gut. They found that even brief episodes of heavy drinking caused injury to the upper small intestine and activated immune responses typically reserved for fighting infections.
The study identified neutrophils — immune cells that can release web-like structures called neutrophil extracellular traps (NETs) — as a key contributor to the damage. These NETs were shown to directly harm the intestinal lining, weakening the barrier and allowing bacterial toxins to leak into the bloodstream.
Notably, when researchers used an enzyme to break down NETs, gut damage was significantly reduced. The treatment lowered immune cell accumulation in the gut lining and decreased bacterial leakage, suggesting a potential pathway for preventing alcohol-related gut injury.