By Health Editor
Geraldine Ohonba
A landmark study has identified harmful gut bacteria as a key driver of deadly liver disease, paving the way for a potential new treatment to combat the condition, which affects millions worldwide.
For decades, liver disease has been closely associated with alcohol abuse. However, experts warn that excess fat and poor diet are now among the leading causes of metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease. The British Liver Trust notes that liver-related deaths have quadrupled in the last 50 years, with the disease now one of the fastest-growing causes of premature death.
Canadian researchers at McMaster University have now discovered a surprising new culprit: a molecule produced by gut microbes called D-lactate, which drives the liver to produce excessive sugar and fat. Lead author Professor Jonathan Schetzer described the findings, published in Cell Metabolism, as “a completely new way to think about treating metabolic diseases like fatty liver disease.”
“Instead of targeting hormones or the liver directly, we’re intercepting a microbial fuel source before it can do harm,” Schetzer explained.
The research builds on the classic “Cori cycle” first described in the 1970s, which showed how muscles produce L-lactate, prompting the liver to generate glucose. But the new study reveals that obese individuals have far higher levels of D-lactate—most of it originating from gut bacteria—raising blood sugar and liver fat far more dramatically than the common L-lactate.
To combat this, the researchers designed a biodegradable “gut substrate trap” to bind D-lactate before it enters the bloodstream. In mouse studies, the treatment significantly lowered blood sugar, improved insulin resistance, and reduced liver inflammation and fibrosis — without requiring any change in diet or body weight.
MASLD is now estimated to affect one in five people in the UK, with obesity, diabetes, sedentary lifestyles, and ageing populations all fueling the surge. If left untreated, the disease can progress to cirrhosis, liver failure, or even cancer. In 2023 alone, 11,000 deaths from liver disease were recorded in the UK, many of which could have been prevented through early detection and lifestyle changes.
Professor Philip Newsome of King’s College London warned that the public still holds a “dangerous misconception” that only alcohol can cause liver scarring. “Excess fat and uncontrolled blood sugar levels can lead to the same outcome,” he said.
The breakthrough discovery has heightened hopes for a new class of treatments that target gut bacteria rather than the liver itself, potentially transforming how fatty liver disease and related metabolic disorders are managed.
