Davidsson Lena, Adou Pierre, Zeder Christophe, Walczyk Thomas, Hurrell Richard
Laboratory for Human Nutrition, Institute of Food Science and Nutrition, Swiss Federal Institute of Technology, PO Box 474, CH-8803 Rüschlikon, Switzerland.
Br J Nutr. 2003 Aug;90(2):337-43. doi: 10.1079/bjn2003914.
Retinyl palmitate added to Fe-fortified maize bread has been reported to enhance Fe absorption in adult Venezuelan subjects but not in Western Europeans. It is not known to what extent these results were influenced by differences in vitamin A status of the study subjects. The objective of the present study was to evaluate the influence of retinyl palmitate added to Fe-fortified maize porridge on erythrocyte incorporation of Fe in children with vitamin A deficiency, before and after vitamin A supplementation. Erythrocyte incorporation of Fe-stable isotopes was measured 14 d after intake of maize porridge (2.0 mg Fe added as ferrous sulfate) with and without added retinyl palmitate (3.5 micromol; 3300 IU). The study was repeated 3 weeks after vitamin A supplementation (intake of a single dose of 210 micromol retinyl palmitate; 'vitamin A capsule'). Vitamin A status was evaluated by the modified relative dose-response (MRDR) technique. Retinyl palmitate added to the test meal reduced the geometric mean erythrocyte incorporation of Fe at baseline from 4.0 to 2.6 % (P=0.008, n 13; paired t test). At 3 weeks after vitamin A supplementation, geometric mean erythrocyte incorporation was 1.9 and 2.3 % respectively from the test meal with and without added retinyl palmitate (P=0.283). Mean dehydroretinol:retinol molar ratios were 0.156 and 0.125 before and after intake of the single dose of 210 micromol retinyl palmitate; 'vitamin A capsule' (P=0.15). In conclusion, retinyl palmitate added to the labelled test meals significantly decreased erythrocyte incorporation of Fe in children with vitamin A deficiency at baseline but had no statistically significant effect 3 weeks after vitamin A supplementation. The difference in response to retinyl palmitate added to Fe-fortified maize porridge on erythrocyte incorporation of Fe before and after intake of the vitamin A capsule indicates, indirectly, changes in vitamin A status not measurable by the MRDR technique. The lack of conclusive data on the effect of retinyl palmitate on Fe absorption indicates the complexity of the interactions between vitamin A status, dietary vitamin A and Fe metabolism.
据报道，添加到铁强化玉米面包中的棕榈酸视黄酯可增强委内瑞拉成年人对铁的吸收，但对西欧人却无此效果。目前尚不清楚这些结果在多大程度上受研究对象维生素A状态差异的影响。本研究的目的是评估在维生素A缺乏的儿童中，添加到铁强化玉米粥中的棕榈酸视黄酯在补充维生素A前后对铁在红细胞中掺入情况的影响。在摄入添加和未添加棕榈酸视黄酯（3.5微摩尔；3300国际单位）的玉米粥（添加2.0毫克硫酸亚铁作为铁）14天后，测量铁稳定同位素在红细胞中的掺入情况。在补充维生素A（摄入单剂量210微摩尔棕榈酸视黄酯；“维生素A胶囊”）3周后重复该研究。通过改良相对剂量反应（MRDR）技术评估维生素A状态。添加到测试餐中的棕榈酸视黄酯使基线时铁在红细胞中的几何平均掺入率从4.0%降至2.6%（P = 0.008，n = 13；配对t检验）。在补充维生素A 3周后，添加和未添加棕榈酸视黄酯的测试餐中铁在红细胞中的几何平均掺入率分别为1.9%和2.3%（P = 0.283）。在摄入单剂量210微摩尔棕榈酸视黄酯；“维生素A胶囊”前后，脱氢视黄醇与视黄醇的平均摩尔比分别为0.156和0.125（P = 0.15）。总之，添加到标记测试餐中的棕榈酸视黄酯在基线时显著降低了维生素A缺乏儿童中铁在红细胞中的掺入率，但在补充维生素A 3周后无统计学显著影响。摄入维生素A胶囊前后，添加到铁强化玉米粥中的棕榈酸视黄酯对铁在红细胞中掺入情况的反应差异间接表明了MRDR技术无法测量的维生素A状态变化。关于棕榈酸视黄酯对铁吸收影响的结论性数据的缺乏表明了维生素A状态、膳食维生素A和铁代谢之间相互作用的复杂性。
