Alcohol misuse can disrupt gut microbiota, causing inflammation that leads to organ damage

Alcohol researchers have long known that excessive drinking can cause damage to the liver, pancreas, heart, muscle, bone, and brain. However, only a subset of patients with alcohol use disorder (AUD) appear to develop organ damage. New research shows that alcohol-induced gut inflammation is the missing link between unhealthy drinking and organ damage among certain AUD patients. These results will be shared at the 47^th annual scientific meeting of the Research Society on Alcohol (RSA) in Minneapolis, Minnesota.

“Recent studies have shown that inflammation is a critical mechanism underpinning alcohol-induced organ damage,” said Ali Keshavarzian, M.D. “One key source of inflammation is gut microbiome dysbiosis and gut leak which occur in only a subset of AUD patients. We show that unhealthy alcohol consumption among certain individuals decreases their resiliency to the detrimental effects of harmful environmental and lifestyle factors, leading to clinically relevant microbiota dysbiosis, intestinal leak, and organ damage.”

Keshavarzian will discuss these findings at the RSA meeting on Monday, 24 June 2024.

“Although high concentrations of alcohol can be toxic to cells and can disrupt cellular function,” explained Keshavarzian,“alcohol-induced tissue and organ damage requires additional inflammation and oxidative stress. One critical question concerned the source of this alcohol-triggered inflammation. Since bacteria residing in the gut is the primary source of endotoxin – a potent bacterial poison – in both animals and humans, we believe that alcohol-induced, gut-derived inflammation is the additional co-factor that can cause clinically relevant organ damage.

Another critical question concerned how alcohol disrupts intestinal barrier function. “We showed that excessive alcohol exposure in both animals and humans disrupts the normal intestinal microbiota community – which includes bacteria, viruses, and fungi – which can then promote endotoxemia by both increasing production of pro-inflammatory bacteria as well as disrupting intestinal barrier function, leading to what is called leaky gut.”

Keshavarzian emphasized that “there is no healthy alcohol consumption for all” because other environmental factors such as diet, sleep patterns, and circadian rhythms can negate the resiliency of individuals to the harmful effects of alcohol. In addition, he said, “unhealthy alcohol consumption decreases the resiliency of individuals to other diseases such as COVID-19 and HIV infection.”

There is hope, Keshavarzian added. “Gut-directed interventions that optimize intestinal microbiota and/or intestinal barrier function, as well as interventions that optimize circadian rhythms, are promising approaches to prevent and/or treat alcohol use disorders and alcohol-associated organ damage.”