Domenico Tricò1,2, Edoardo Biancalana3, Anna Solini1. 1. Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa. 2. Institute of Life Sciences, Sant'Anna School of Advanced Studies. 3. Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.
Abstract
PURPOSE OF REVIEW: In this review, the latest evidence on the influence of dietary protein and plasma amino acids in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) is discussed. RECENT FINDINGS: Increasing protein consumption during weight loss and maintenance may help reduce liver fat content. Conversely, high protein intake characteristic of the unhealthy Western diet is associated with increased NAFLD prevalence and severity. Plasma concentration of several amino acids, including branched-chain (BCAA) and aromatic amino acids (AAA), is altered in NAFLD. Excess amino acid availability contributes to intrahepatic fat accumulation and may reflect poor dietary habits and dysregulation of amino acid metabolic processing in both liver and peripheral tissues. Specific amino acid patterns, characterized by increased BCAA, AAA, alanine, glutamate, lysine levels, and decreased glycine and serine levels, may be used for early detection of NAFLD and noninvasive assessment of its histological severity. SUMMARY: Mechanistic studies in NAFLD have been mostly focused on carbohydrate and fat metabolism, while little is known about the influence of protein and amino acids. Moreover, intervention and observational studies on the relation between protein intake and NAFLD yielded conflicting results. Filling the current knowledge gaps would help define the optimal diet composition for NAFLD prevention and management. Furthermore, metabolomics studies may provide insight into the pathogenesis of NAFLD, identify useful diagnostic and prognostic biomarkers, and unravel novel pharmacological targets and treatment options.
PURPOSE OF REVIEW: In this review, the latest evidence on the influence of dietary protein and plasma amino acids in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) is discussed. RECENT FINDINGS: Increasing protein consumption during weight loss and maintenance may help reduce liver fat content. Conversely, high protein intake characteristic of the unhealthy Western diet is associated with increased NAFLD prevalence and severity. Plasma concentration of several amino acids, including branched-chain (BCAA) and aromatic amino acids (AAA), is altered in NAFLD. Excess amino acid availability contributes to intrahepatic fat accumulation and may reflect poor dietary habits and dysregulation of amino acid metabolic processing in both liver and peripheral tissues. Specific amino acid patterns, characterized by increased BCAA, AAA, alanine, glutamate, lysine levels, and decreased glycine and serine levels, may be used for early detection of NAFLD and noninvasive assessment of its histological severity. SUMMARY: Mechanistic studies in NAFLD have been mostly focused on carbohydrate and fat metabolism, while little is known about the influence of protein and amino acids. Moreover, intervention and observational studies on the relation between protein intake and NAFLD yielded conflicting results. Filling the current knowledge gaps would help define the optimal diet composition for NAFLD prevention and management. Furthermore, metabolomics studies may provide insight into the pathogenesis of NAFLD, identify useful diagnostic and prognostic biomarkers, and unravel novel pharmacological targets and treatment options.
Authors: Jukka Hintikka; Sanna Lensu; Elina Mäkinen; Sira Karvinen; Marjaana Honkanen; Jere Lindén; Tim Garrels; Satu Pekkala; Leo Lahti Journal: Int J Environ Res Public Health Date: 2021-04-12 Impact factor: 3.390
Authors: Sofina Begum; Blair Z Johnson; Aude-Claire Morillon; Rongchang Yang; Sze How Bong; Luke Whiley; Nicola Gray; Vanessa S Fear; Leila Cuttle; Andrew J A Holland; Jeremy K Nicholson; Fiona M Wood; Mark W Fear; Elaine Holmes Journal: Sci Rep Date: 2022-07-29 Impact factor: 4.996