Allen Lindsay H
USDA, ARS Western Human Nutrition Research Center, University of California, Davis, CA, USA.
Nestle Nutr Inst Workshop Ser. 2012;70:175-83. doi: 10.1159/000337775. Epub 2012 Aug 31.
There is no doubt that folic acid fortification can be effective for reducing the incidence of neural tube defects. The degree of efficacy depends on both the level of folate depletion and other, yet to be fully characterized, genetic and/or environmental factors. This article summarizes briefly data on neural tube defect reduction and other benefits of folic acid fortification as these have been reviewed in more detail elsewhere. More attention is drawn to questions that have been raised about the possible adverse effects of folic acid fortification including the incidence of colorectal cancer and immune function. The main question addressed here is whether folic acid fortification can exacerbate the adverse effects of vitamin B12 deficiency. Most analyses of this question have been conducted in wealthier countries based on data from elderly populations - which have the highest prevalence of vitamin B12 deficiency. However, of potentially greater concern is the increasingly common practice of folic acid fortification in developing countries, where folate status is probably often adequate even prior to fortification, and vitamin B12 depletion or deficiency is common. To add to this information, data from a group of Chilean elderly with a range of vitamin B12 status and exposed to high levels of folic acid fortification will be presented.
毫无疑问，叶酸强化可有效降低神经管缺陷的发生率。其功效程度取决于叶酸缺乏水平以及其他尚未完全明确的遗传和/或环境因素。本文简要总结了有关叶酸强化降低神经管缺陷及其他益处的数据，这些内容在其他地方已有更详细的综述。本文更多关注的是关于叶酸强化可能产生的不利影响所引发的问题，包括结直肠癌的发病率和免疫功能。这里探讨的主要问题是叶酸强化是否会加剧维生素B12缺乏的不利影响。关于这个问题的大多数分析是在较富裕的国家基于老年人群的数据进行的，而老年人群中维生素B12缺乏的患病率最高。然而，潜在更令人担忧的是发展中国家越来越普遍的叶酸强化做法，在这些国家，即使在强化之前叶酸状况可能通常就足够了，而维生素B12耗竭或缺乏却很常见。为补充这方面的信息，将展示一组智利老年人的数据，他们具有不同的维生素B12状况且接触了高水平的叶酸强化。
