The incidence of nonalcoholic fatty liver disease (NAFLD) is increasing worldwide. It is the leading cause of abnormal liver enzymes and is associated with diabetes and obesity. Long term hyperglycemia causes an increase in the synthesis of fatty acids and triglycerides in the liver, leading to fatty liver.

At this time there are few guidelines for diagnostic and follow-up methods and limited proven treatment options. Previous research of pharmacological agents to treat NAFLD garnered poor results.

Insulin resistance is one of the key factors in the development of NAFLD; however, the gut-liver axis is a significant contributor as well. Gut dysbiosis and intestinal hyperpermeability lead to liver damage from proinflammatory responses.

According to a new review published on Monday, researchers investigated the role of probiotics via the gut-liver axis in NAFLD. Findings show an increasing body of research has demonstrated that dysbiosis can negatively impact immune and metabolic processes. One study showed increased intestinal permeability as well as small intestinal bacterial overgrowth in 35 consecutive patients with NAFLD proven on biopsy. These abnormal findings correlated with disease severity. In addition, an imbalance in the ratio of Bacteroidetes and Firmicutes has been reported in obese patients with nonalcoholic steatohepatitis (NASH) one of the conditions that falls under the larger umbrella of NAFLD.

Other recent research suggests the presence of a gut microbiota-derived signature, which predicts the presence of advanced fibrosis in NAFLD patients. Researchers analyzed the bacteria composition of 86 biopsy-proven NAFLD patients in which 72 had mild fibrosis and 14 had advanced fibrosis. As a result, they identified 37 different bacterial species where they could distinguish mild and advanced fibrosis by an increase of Proteobacteria and Escherichia coli and a decrease in Firmicutes.

There have been some recent promising findings for probiotics in NAFLD and cirrhosis. A study including 30 adults with NASH demonstrated a reduction of liver enzymes with Lactobacillus acidophilus compared to placebo; however, probiotics delivered in multi-strain formulas have shown better clinical outcomes in randomized trials. A triple blinded trial including 64 obese children with NAFLD received a probiotic including Lactobacillus acidophilus, Bifidobacterium lactis, Bifidobacterium bifidum, and Lactobacillus rhamnosus over a 12-week period. As a result, there was a significant reduction in liver enzymes, lipid profile, and intrahepatic fat compared to the placebo group.

Probiotics can help restore the gastrointestinal barrier function, modulate the immune system, and inhibit the proliferation of harmful bacteria. They have been shown to reduce liver fat and improve liver enzymes. Probiotics are likely most effective by preventing bacterial translocation and reducing the effects of the intestinal microbiota on the liver.

Additional nutrients to consider include, delta and gamma tocotrienols, fish oil, CoQ10, berberine, and milk thistle to help mitigate the progression and improve liver function in patients with NAFLD. It is also essential to encourage exercise and recommend a restricted carbohydrate diet to support weight loss in these individuals.

By Michael Jurgelewicz, DC, DACBN, DCBCN, CNS

Source: Meroni M, Longo M, et al. The Role of Probiotics in Nonalcoholic Fatty Liver Disease: A New Insight into Therapeutic Strategies. Nutrients. 4 November 2019, 11(11), 2642.