High Protein Intake Is Associated With Histological Disease Activity in Patients With NAFLD

Abstract

Overconsumption of carbohydrates and lipids are well known to cause nonalcoholic fatty liver disease (NAFLD), while the role of nutritional protein intake is less clear. In Western diet, meat and other animal products are the main protein source, with varying concentrations of specific amino acids. Whether the amount or composition of protein intake is associated with a higher risk for disease severity has not yet been examined. In this study, we investigated associations of dietary components with histological disease activity by analyzing detailed 14-day food records in a cohort of 61 patients with biopsy-proven NAFLD. Furthermore, we used 16S ribosomal RNA gene sequencing to detect associations with different abundances of the gut microbiota with dietary patterns. Patients with definite nonalcoholic steatohepatitis (NAFLD activity score of 5-8 on liver biopsy) had a significantly higher daily relative intake of protein compared with patients with a NAFLD activity score of 0-4 (18.0% vs. 15.8% of daily protein-based calories, P = 0.018). After adjustment for several potentially confounding factors, a higher protein intake (≥17.3% of daily protein-based calories) remained associated with definite nonalcoholic steatohepatitis, with an odds ratio of 5.09 (95% confidence interval 1.22-21.25, P = 0.026). This association was driven primarily by serine, glycine, arginine, proline, phenylalanine, and methionine. A higher protein intake correlated with a lower Bacteroides abundance and an altered abundance of several other bacterial taxa. Conclusion: A high protein intake was independently associated with more active and severe histological disease activity in patients with NAFLD. Further studies are needed to investigate the potential harmful role of dietary amino acids on NAFLD, with special attention to meat as their major source. (Hepatology Communications 2020;4:681-695).

Overview of Non-Alcoholic Fatty Liver Disease (NAFLD) and the Role of Sugary Food Consumption and Other Dietary Components in Its Development

“…There are few data related to the effect of protein consumption on the development of NAFLD, and the results obtained are quite heterogeneous. It has been reported that high protein intake could have a negative, neutral, or even positive effect on NAFLD [ 125 , 126 , 127 , 128 ]. The best explanation for this controversy is that animal and vegetable proteins could exert opposite effects.…”

“…Furthermore, intervention and observational studies on the relationship between protein and NAFLD show conflicting results. Some studies found evidence that higher protein intakes might have a negative effect on NAFLD, while other studies showed a neutral or positive effect [ 125 , 126 ]. These inconsistencies might be explained by the type of protein consumed, as animal protein seems to have a negative effect on NAFLD, while plant protein has an inverse association [ 125 ].…”

Intestinal Virome Signature Associated With Severity of Nonalcoholic Fatty Liver Disease

“…The 16S ribosomal RNA gene sequencing of human stool samples was performed as previously described. 28…”

Oxidative Stress in NAFLD: Role of Nutrients and Food Contaminants

“…A recent study analyzed the effects of isocaloric diets rich in animal proteins or plant proteins for 6 weeks in patients with diabetes and NAFLD and found that both high-protein diets reduced liver fat [ 68 ]. However, high consumption of proteins and of red and/or processed meat has been reported in patients with NASH [ 69 , 70 ]. The Rotterdam study further showed that a high animal protein intake is associated with a higher prevalence of hepatic steatosis in overweight and elderly patients [ 71 ].…”