Perry Cydne A, Renna Stacey A, Khitun Elena, Ortiz Monica, Moriarty David J, Caudill Marie A
Department of Human Nutrition and Food Science, Cal Poly Pomona University, Pomona, CA 91768, USA.
J Nutr. 2004 Jul;134(7):1786-92. doi: 10.1093/jn/134.7.1786.
Population-based studies report differences in folate status indicators among Mexican American (MA), African American (AA) and Caucasian (CA) women. It is unclear, however, whether these differences are due to variations in dietary folate intake. The present study was designed to investigate the influence of ethnicity/race on folate status parameters in MA, AA, and CA women (18-45 y; n = 14 in each group) under conditions of strictly controlled folate intake. In addition, the adequacy of the 1998 folate U.S. recommended dietary allowance (RDA), 400 micro g/d as dietary folate equivalents (DFE), for non-Caucasian women was assessed. Subjects (n = 42) with the methylenetetrahydrofolate reductase 677 CC genotype consumed a low-folate diet (135 micro g DFE/d) for 7 wk followed by repletion with 400 (7 MA, 7 AA, 7 CA) or 800 micro g DFE/d (7 MA, 7 AA, 7 CA) for 7 wk. AA women had lower (P </= 0.05) blood folate concentrations and excreted less (P </= 0.05) urinary folate throughout folate depletion and repletion with 400 and/or 800 micro g DFE/d compared with MA and/or CA women. MA women had lower (P </= 0.05) plasma total homocysteine (tHcy) throughout folate depletion and during repletion with 400 micro g DFE/d relative to the other ethnic/racial groups. Repletion with the 1998 folate U.S. RDA led to normal blood folate and plasma tHcy for all 3 ethnic/racial groups. Collectively, these data demonstrate that ethnicity/race is an important determinant of folate status under conditions of strictly controlled dietary folate intake and support the adequacy of the 1998 folate U.S. RDA for the 3 largest ethnic/racial groups in the United States.
基于人群的研究报告了墨西哥裔美国人(MA)、非裔美国人(AA)和白种人(CA)女性在叶酸状态指标上的差异。然而,尚不清楚这些差异是否归因于膳食叶酸摄入量的变化。本研究旨在调查在严格控制叶酸摄入量的条件下,种族对MA、AA和CA女性(18 - 45岁;每组n = 14)叶酸状态参数的影响。此外,还评估了1998年美国叶酸推荐膳食摄入量(RDA),即400μg/d膳食叶酸当量(DFE)对非白种女性的充足性。具有亚甲基四氢叶酸还原酶677 CC基因型的受试者(n = 42)先食用低叶酸饮食(135μg DFE/d)7周,随后分别补充400(7名MA、7名AA、7名CA)或800μg DFE/d(7名MA、7名AA、7名CA)7周。与MA和/或CA女性相比,在整个叶酸耗竭期以及补充400和/或800μg DFE/d的过程中,AA女性的血液叶酸浓度较低(P≤0.05),尿叶酸排泄量较少(P≤0.05)。相对于其他种族/族裔群体,在整个叶酸耗竭期以及补充400μg DFE/d期间,MA女性的血浆总同型半胱氨酸(tHcy)较低(P≤0.05)。用1998年美国叶酸RDA进行补充后,所有3个种族/族裔群体的血液叶酸和血浆tHcy均恢复正常。总体而言,这些数据表明,在严格控制膳食叶酸摄入量的条件下,种族是叶酸状态的重要决定因素,并支持1998年美国叶酸RDA对美国3个最大种族/族裔群体的充足性。