The prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing worldwide. Its etiology includes nutritional, genetic, and lifestyle factors. Several mechanisms may link one-carbon metabolism – the associated metabolic pathways of folate, methionine, and choline – to the onset of NAFLD. In this review, we attempted to assess how choline, folate, methionine, and betaine affect NAFLD development, mainly through their role in the secretion of very low-density lipoproteins (VLDL) from the liver. We also reviewed recent articles that have described the relation between microbiota metabolism and NAFLD progression. Moreover, we describe the effect of single-nucleotide polymorphisms (SNP) in genes related to one-carbon metabolism and disease prevalence. We additionally seek SNP identified by genome-wide associations that may increase the risk of this disease. Even though the evidence available is not entirely consistent, it seems that the concentrations of choline, methionine, folate, and betaine may affect the progression of NAFLD. Since there is no effective therapy for NAFLD, further investigations into the link between nutrition, gut microbiota, genetic factors, and NAFLD are still necessary, with a particular emphasis on methyl donors.

中文翻译：

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一碳代谢与非酒精性脂肪肝：营养素、微生物群和遗传学之间的串扰

非酒精性脂肪性肝病 (NAFLD) 的患病率在全球范围内不断增加。其病因包括营养、遗传和生活方式因素。几种机制可能将一碳代谢（叶酸、蛋氨酸和胆碱的相关代谢途径）与 NAFLD 的发病联系起来。在这篇综述中，我们试图评估胆碱、叶酸、蛋氨酸和甜菜碱如何影响 NAFLD 的发展，主要是通过它们在肝脏分泌极低密度脂蛋白 (VLDL) 中的作用。我们还回顾了最近描述微生物群代谢与 NAFLD 进展之间关系的文章。此外，我们描述了单核苷酸多态性 (SNP) 在与一碳代谢和疾病流行相关的基因中的影响。我们还寻求通过全基因组关联确定的可能会增加这种疾病风险的 SNP。尽管现有证据并不完全一致，但胆碱、蛋氨酸、叶酸和甜菜碱的浓度似乎可能会影响 NAFLD 的进展。由于 NAFLD 没有有效的治疗方法，因此仍需要进一步研究营养、肠道微生物群、遗传因素和 NAFLD 之间的联系，尤其是甲基供体。