Department of Internal Medicine, University of Calgary (Foothills Hospital), 1403 - 29 Street NW, Calgary, AB, Canada.
Med Hypotheses. 2012 Apr;78(4):489-93. doi: 10.1016/j.mehy.2012.01.014. Epub 2012 Jan 28.
It is recognized that alcohol consumption during pregnancy is associated with fetal alcohol syndrome (FAS). Alcohol can trigger a pattern of neurodegeneration in rat brains similar to other known gamma-aminobutyric acid (GABA) specific agonists. However this does not seem to explain FAS entirely, as impoverished care-giving environments have been shown to increase the risk of FAS. Individuals living under the poverty level are at risk for micronutrient deficiencies due to insufficient intake. In particular, three nutrients commonly found to be deficient are folate, choline and vitamin A. There is evidence to suggest that ethanol alone may not explain the entire spectrum of anomalies seen in individuals with FAS. It is hypothesized that FAS may be caused more by the nutritional deficiencies that are exacerbated by alcohol than by direct alcoholic neurotoxicity. It is known that ethanol inhibits folate, choline, and vitamin A/retinoic acid metabolism at multiple steps. Additionally, mice exposed to ethanol demonstrated epigenetic changes, or variations in the methylation of DNA to control gene expression. Folate is important in the production of methyl groups, which are subsequently used to create and methylate DNA. Choline (which is metabolized to acetylcholine) is important in neurotransmission and neurodevelopment. It is also involved in an alternative pathway in the production of methyl groups. In fact a study by Thomas et al. in 2009 found that nutritional supplementation with choline in rats exposed to ethanol in utero almost completely mitigated the degenerative effects of ethanol on development and behaviour. Lastly, vitamin A and retinoic acid metabolism is associated with the regulation of one sixth of the entire proteome. Thus supplementation of folate, choline and vitamin A to mothers may mitigate the effects of the alcohol and reduce the severity or prevalence of FAS.
人们认识到,怀孕期间饮酒会导致胎儿酒精综合征(FAS)。酒精可在老鼠大脑中引发类似其他已知γ-氨基丁酸(GABA)特定激动剂的神经退行性模式。然而,这似乎并不能完全解释 FAS,因为有研究表明,贫困的养育环境会增加 FAS 的风险。生活在贫困线以下的人由于摄入不足,存在微量营养素缺乏的风险。特别是,三种常见的缺乏营养素有叶酸、胆碱和维生素 A。有证据表明,仅乙醇可能无法解释 FAS 个体中所见的所有异常。据推测,FAS 可能更多地是由于营养缺乏所致,而这些营养缺乏又因酒精而恶化,而不是由于直接的酒精神经毒性。众所周知,乙醇可在多个步骤中抑制叶酸、胆碱和维生素 A/视黄酸代谢。此外,接触乙醇的老鼠表现出表观遗传变化,即 DNA 甲基化的变化,以控制基因表达。叶酸在产生甲基基团中很重要,随后甲基基团用于创建和甲基化 DNA。胆碱(可代谢为乙酰胆碱)在神经传递和神经发育中很重要。它也参与了产生甲基基团的替代途径。事实上,Thomas 等人在 2009 年进行的一项研究发现,在暴露于乙醇的老鼠中用胆碱进行营养补充几乎完全减轻了乙醇对发育和行为的退行性影响。最后,维生素 A 和视黄酸代谢与调节整个蛋白质组的六分之一有关。因此,给母亲补充叶酸、胆碱和维生素 A 可能会减轻酒精的影响,降低 FAS 的严重程度或发生率。