Tricò Domenico, Biancalana Edoardo, Solini Anna
Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa.
Institute of Life Sciences, Sant'Anna School of Advanced Studies.
Curr Opin Clin Nutr Metab Care. 2021 Jan;24(1):96-101. doi: 10.1097/MCO.0000000000000706.
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.
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.
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.
本综述讨论了饮食蛋白质和血浆氨基酸在非酒精性脂肪性肝病（NAFLD）发病机制中的最新证据。
在减肥和维持体重期间增加蛋白质摄入量可能有助于降低肝脏脂肪含量。相反，不健康西方饮食的高蛋白摄入特征与NAFLD患病率和严重程度增加有关。在NAFLD中，包括支链氨基酸（BCAA）和芳香族氨基酸（AAA）在内的几种氨基酸的血浆浓度会发生改变。过量的氨基酸供应会导致肝内脂肪堆积，这可能反映出不良的饮食习惯以及肝脏和外周组织中氨基酸代谢过程的失调。以BCAA、AAA、丙氨酸、谷氨酸、赖氨酸水平升高以及甘氨酸和丝氨酸水平降低为特征的特定氨基酸模式，可用于NAFLD的早期检测及其组织学严重程度的无创评估。
NAFLD的机制研究大多集中在碳水化合物和脂肪代谢上，而对蛋白质和氨基酸的影响知之甚少。此外，关于蛋白质摄入量与NAFLD之间关系的干预性研究和观察性研究得出了相互矛盾的结果。填补当前的知识空白将有助于确定预防和管理NAFLD的最佳饮食组成。此外，代谢组学研究可能会深入了解NAFLD的发病机制，识别有用的诊断和预后生物标志物，并揭示新的药理学靶点和治疗选择。
