Probiotic, prebiotic use confer benefits in NAFLD
Supplementation with probiotics and/or prebiotics may be an effective strategy to improve inflammatory, oxidative, and anthropometric markers in patients with non-alcoholic fatty liver disease (NAFLD), a new study shows.
Seventy-five individuals with NAFLD (mean age 42 years, mean BMI 30.8 kg/m2) were randomized 1:1:1:1 to receive a probiotic comprising Bifidobacterium longum and Lactobacillus acidophilus (2 × 107 CFU/day), the prebiotic inulin (10 g/day), both the probiotic and prebiotic (combo regimen), or placebo for three months. [Asia Pac J Clin Nutr 2018;27:1031-1039]
Consumption of probiotics and prebiotics either alone or combined fared better than placebo in reducing tumour necrosis factor-alpha (TNF-α, mean, -0.51, -0.21, and -0.14 pg/mL for probiotic, prebiotic, and combo regimen, respectively vs 1.07 pg/mL for placebo; p=0.03)
According to the researchers, it is important to manage the level of TNF-α as it plays a key role in the pathogenesis of NAFLD/non-alcoholic steatohepatitis (NASH). Reducing TNF-α levels may help prevent the progression of NAFLD to NASH, which could further progress into cirrhosis and hepatocellular carcinoma if left untreated. [Biochem Biophys Res Commun 2010;391:1731-1736; Free Radic Biol Med 2012;52:59-69]
The combo regimen was more effective than using probiotics or prebiotics alone in reducing another inflammatory marker, high-sensitive C-reactive protein (mean, -0.93 mg/L [combo] vs -0.17 and -0.30 mg/L for probiotic and prebiotic, respectively; p<0.01).
Researchers attributed the improved inflammatory parameters to the ability of the probiotic to prevent endotoxin displacement from the intestines to the blood. [J Gastrointest Dig Syst 2014;4:245; Trends Endocrinol Metab 2013;24:537-545] Other potential contributing factors are the increased intestinal permeability and reduced proinflammatory parameters. [Therap Adv Gastroenterol 2016;9:463-472; J Microbiol Biotechnol 2013; 23:518-526]
Oxidative stress was better addressed by probiotics and prebiotics either alone or combined than placebo by increasing the serum levels of total antioxidant capacity (mean, 0.44, 0.18, and 0.40 mmol/L for probiotic, prebiotic, and combo regimen, respectively vs -0.10 mmol/L; p=0.01).
Although the exact mechanism remains unclear, possible mechanisms that could be responsible for the improvement in oxidative stress are the neutralization of oxidants in the intestinal tract through the expression of antioxidant enzymes, reduction of inflammation, and inhibition of intestinal pathogens that reduce inflammation and associated oxidative damage, noted the researchers. [Int J Mol Sci 2016;17:pii:E928; Oxid Med Cell Longev 2016;2016:1340903]
Probiotic and prebiotic supplementation also yielded significant reductions in body weight compared with placebo (mean, -1.8, -2.0, and -2.0 kg for probiotic, prebiotic, and combo regimen, respectively vs 0.5 kg for placebo; p=0.01), BMI (mean, -0.65, -0.58, and -0.83 kg/m2, respectively vs 0.18 kg/m2; p=0.01), waist circumference (mean, -1.2, -2.0, and -1.0 cm, respectively vs 1.0 cm; p=0.01), and hip circumference (mean, -1.0, -1.0, and -2.0 cm, respectively vs 1.0 cm; p=0.01).
This anti-obesity effect of probiotics/prebiotics could have been due to appetite suppression, increased energy expenditure, or altered lipid, choline, and bile acid metabolism, [Aliment Pharmacol Ther 2014;39:1276-1285; Nutr Neurosci 2015;18:49-65] or through the inhibition of the hunger hormone ghrelin and enhancement of peptide YY and glucagon-like peptide-1 which could contribute to the reduction in energy intake. [Am J Clin Nutr 2009;89:1751-1759]
“Body weight and BMI are important factors in the pathogenesis of NAFLD,” said the researchers, citing evidence demonstrating that a 7–10-percent body weight reduction may aid in the management of NAFLD. [World J Hepatol 2015;7:2962-2967]
“[Taken together, our findings show that] probiotics and/or prebiotics can be considered as an adjuvant therapy for NAFLD patients,” said the researchers. Nonetheless, the lack of evaluation on intestinal bacteria and short-chain fatty acids, as well as the short study duration warrant larger trials with longer follow-ups to better elucidate the effects of probiotics/prebiotics in NAFLD, they said. Moreover, the use of ultrasound imaging instead of liver biopsy to assess disease severity might have also influenced the findings, they added.