Centers for Disease Control and Prevention (CDC), National Center for Environmental Health, Atlanta, GA, USA.
National Institutes of Health, Office of Dietary Supplements, Bethesda, MD, USA.
J Nutr. 2020 Apr 1;150(4):851-860. doi: 10.1093/jn/nxz278.
Serum folate forms were measured in the US population during recent NHANES to assess folate status.
We describe post-folic acid-fortification concentrations of serum folate forms in the fasting US population ≥1 y from the NHANES 2011-2016.
We measured 5 biologically active folates and 1 oxidation product (MeFox) of 5-methyltetrahydrofolate (5-methyl-THF). We calculated geometric means of 5-methyl-THF, unmetabolized folic acid (UMFA), nonmethyl folate (sum of tetrahydrofolate, 5-formyltetrahydrofolate, and 5,10-methenyltetrahydrofolate), total folate (sum of above biomarkers), and MeFox by demographic, physiologic, and lifestyle variables; estimated the magnitude of variables on biomarker concentrations after covariate adjustment; and determined the prevalence of UMFA >2 nmol/L.
After demographic adjustment, age, sex, and race-Hispanic origin were significantly associated with most folate forms. MeFox increased with age, while 5-methyl-THF, UMFA, and nonmethyl folate displayed U-shaped age patterns. Compared with non-Hispanic whites, non-Hispanic blacks had 23% lower predicted 5-methyl-THF but comparable UMFA; non-Hispanic Asians had comparable 5-methyl-THF but 28% lower UMFA; Hispanics, non-Hispanic Asians, and non-Hispanic blacks had ∼20% lower MeFox. After additional physiologic and lifestyle adjustment, predicted UMFA and MeFox concentrations were 43% and 112% higher, respectively, in adults with chronic kidney disease and 17% and 15% lower, respectively, in adults consuming daily 1-<2 alcoholic beverages; 5-methyl-THF concentrations were 20% lower in adult smokers. The prevalence of UMFA >2 nmol/L was highest in persons aged ≥70 y (9.01%) and lowest in those aged 12-19 y (1.14%). During 2011-2014, the prevalence was 10.6% in users and 2.22% in nonusers of folic acid-containing supplements.
In fasting persons ≥1 y, the demographic, physiologic, and lifestyle characteristics observed with serum total folate differed among folate forms, suggesting biological and/or genetic influences on folate metabolism. High UMFA was mostly observed in supplement users and older persons.
在美国人群中，最近的 NHANES 期间测量了血清叶酸形式，以评估叶酸状况。
我们描述了 NHANES 2011-2016 期间，空腹美国人群中叶酸强化后的血清叶酸形式的浓度。
我们测量了 5 种生物活性叶酸和 1 种 5-甲基四氢叶酸（5-甲基-THF）的氧化产物（MeFox）。我们按人口统计学、生理学和生活方式变量计算了 5-甲基-THF、未代谢叶酸（UMFA）、非甲基叶酸（四氢叶酸、5-甲酰四氢叶酸和 5,10-亚甲基四氢叶酸之和）、总叶酸（上述生物标志物之和）和 MeFox 的几何平均值；估计了调整协变量后生物标志物浓度的变量幅度；并确定了 UMFA>2nmol/L 的患病率。
经过人口统计学调整后，年龄、性别和种族-西班牙裔起源与大多数叶酸形式显著相关。MeFox 随年龄增长而增加，而 5-甲基-THF、UMFA 和非甲基叶酸呈 U 形年龄模式。与非西班牙裔白人相比，非西班牙裔黑人的预测 5-甲基-THF 低 23%，但 UMFA 相当；非西班牙裔亚洲人的 5-甲基-THF 相当，但 UMFA 低 28%；西班牙裔、非西班牙裔亚洲人和非西班牙裔黑人的 MeFox 低 20%左右。在进行了额外的生理和生活方式调整后，患有慢性肾脏病的成年人的预测 UMFA 和 MeFox 浓度分别高 43%和 112%，而每天饮用 1-<2 份酒精饮料的成年人分别低 17%和 15%；成年吸烟者的 5-甲基-THF 浓度低 20%。UMFA>2nmol/L 的患病率在≥70 岁的人群中最高（9.01%），在 12-19 岁的人群中最低（1.14%）。在 2011-2014 年，使用者的患病率为 10.6%，而非使用者的患病率为 2.22%。
在空腹≥1 岁的人群中，血清总叶酸的人口统计学、生理学和生活方式特征与叶酸形式不同，表明叶酸代谢存在生物学和/或遗传影响。高 UMFA 主要见于补充剂使用者和老年人。
