Verhoef P, Katan M B
Wageningen Centre for Food Sciences en Wageningen Universiteit, afd. Humane Voeding, Bomenweg 2, 6703 HD Wageningen.
Ned Tijdschr Geneeskd. 2006 Jul 1;150(26):1439-42.
Periconceptional supplemention with folic acid prevents neural-tube defects in infants. However, contrary to expectations, clinical trials found no beneficial effect of folic acid on the recurrence of cardiovascular disease. Trial evidence on folic acid and cognitive decline or dementia is scarce, though observational studies suggest that high folate intake may prevent these disorders. In contrast, animal studies suggest that high doses of folic acid enhance the growth of existing tumours. However, recent clinical trials failed to show significant effects of folic acid on cancer incidence and mortality. There are also speculations that folic-acid fortification may increase the number of newborns with the thermolabile variant of methylene tetrahydrofolate reductase. There appears to be little evidence that folic-acid supplementation may mask vitamin-B12 deficiency. In view of these controversies, it is unlikely that The Netherlands will mandate folic-acid fortification of staple foods in the near future. Therefore, women who are planning a pregnancy should be urged to take folic-acid supplements.
孕期补充叶酸可预防婴儿神经管缺陷。然而，与预期相反，临床试验发现叶酸对心血管疾病复发没有有益影响。关于叶酸与认知能力下降或痴呆症的试验证据很少，尽管观察性研究表明高叶酸摄入量可能预防这些疾病。相比之下，动物研究表明高剂量叶酸会促进现有肿瘤的生长。然而，最近的临床试验未能显示叶酸对癌症发病率和死亡率有显著影响。也有推测认为叶酸强化可能会增加携带亚甲基四氢叶酸还原酶热不稳定变体的新生儿数量。几乎没有证据表明补充叶酸会掩盖维生素B12缺乏症。鉴于这些争议，荷兰近期不太可能强制对主食进行叶酸强化。因此，应敦促计划怀孕的女性服用叶酸补充剂。
