Ek J
Am J Clin Nutr. 1983 Dec;38(6):929-35. doi: 10.1093/ajcn/38.6.929.
Folacin concentrations (Lactobacillus casei activity) in human milk, in plasma and red blood cells, and other pertinent blood values have been studied in 91 women during the 1st yr after parturition. Iron but no folic acid supplementation was given. The women were divided into three groups according to the duration of the lactation period, group A 6-greater than 12, group B 1-less than 6 and group C less than 1 month, respectively. The women in groups A, B, and C showed no signs of folacin deficiency as judged from the plasma and red cell folacin concentrations and the peripheral red blood cell picture. The folacin concentration in human milk increased during the first 3 months after parturition. Toward the end of the lactation period the folacin concentration in human milk decreased. We conclude that in this population the folacin intake is adequate to meet the increased requirements during lactation, and folic acid supplementation is therefore not recommended as a routine during lactation. The women in group A had significantly higher red cell folacin concentrations both at parturition and 12 months later than the women in group C. The study suggests a relationship between the nutritional status of the mothers and the length of the lactation period, and provide further evidence to the hypothesis that there exist regulatory mechanisms to maintain the folacin concentrations in human milk.
对91名女性在产后第1年的母乳、血浆和红细胞中的叶酸浓度（干酪乳杆菌活性）以及其他相关血液指标进行了研究。研究期间仅补充了铁剂，未补充叶酸。根据哺乳期的长短，将这些女性分为三组，A组哺乳期大于6至12个月，B组哺乳期1至小于6个月，C组哺乳期小于1个月。从血浆和红细胞叶酸浓度以及外周红细胞图像判断，A、B、C三组女性均未出现叶酸缺乏的迹象。产后前3个月母乳中的叶酸浓度升高，哺乳期快结束时母乳中的叶酸浓度降低。我们得出结论，在这一人群中，叶酸摄入量足以满足哺乳期增加的需求，因此不建议将补充叶酸作为哺乳期的常规做法。A组女性在分娩时和12个月后的红细胞叶酸浓度均显著高于C组女性。该研究表明母亲的营养状况与哺乳期长短之间存在关联，并为存在维持母乳中叶酸浓度的调节机制这一假说提供了进一步的证据。
