Menzie Carolyn M, Yanoff Lisa B, Denkinger Blakeley I, McHugh Teresa, Sebring Nancy G, Calis Karim A, Yanovski Jack A
Unit on Growth and Obesity, National Institutes of Health, Hatfield Clinical Research Center, Bethesda, MD 20892-1103, USA.
J Am Diet Assoc. 2008 Jan;108(1):145-8. doi: 10.1016/j.jada.2007.10.034.
Hypoferremia is more prevalent in obese than nonobese adults, but the reason for this phenomenon is unknown. To elucidate the role dietary factors play in obesity-related hypoferremia, the intake of heme and nonheme iron and the intake of other dietary factors known to affect iron absorption were compared cross-sectionally from April 2002 to December 2003 in a convenience sample of 207 obese and 177 nonobese adults. Subjects completed 7-day food records, underwent phlebotomy for serum iron measurement, and had body composition assessed by dual-energy x-ray absorptiometry, during a 21-month period. Data were analyzed by analysis of covariance and multiple linear regression. Serum iron (mean+/-standard deviation) was significantly lower in obese than nonobese individuals (72.0+/-61.7 vs 85.3+/-58.1 microg/dL [12.888+/-11.0443 vs 15.2687+/-10.3999 micromol/L]; P<0.001). The obese cohort reported consuming more animal protein (63.6+/-34.5 vs 55.7+/-32.5 g/day; P<0.001) and more heme iron (3.6+/-2.8 vs 2.7+/-2.6 mg/day; P<0.001). Groups did not differ, however, in total daily iron consumption, including supplements. Obese subjects reported consuming less vitamin C (77.2+/-94.9 vs 91.8+/-89.5 mg/day; P=0.01), which may increase absorption of nonheme iron, and less calcium (766.2+/-665.0 vs 849.0+/-627.2 mg/day; P=0.038), which may decrease nonheme iron absorption, than nonobese subjects. Groups did not significantly differ in intake of other dietary factors that can impact absorption of iron, including phytic acid, oxalic acid, eggs, coffee, tea, zinc, vegetable protein, or copper. After accounting for demographic covariates and dietary factors expected to affect iron absorption, fat mass (P=0.007) remained a statistically significant negative predictor of serum iron. This cross-sectional, exploratory study suggests that obesity-related hypoferremia is not associated with differences in reported intake of heme and nonheme iron or intake of dietary factors that can affect iron absorption.
低铁血症在肥胖成年人中比非肥胖成年人更为普遍，但这种现象的原因尚不清楚。为了阐明饮食因素在肥胖相关低铁血症中所起的作用，2002年4月至2003年12月期间，在一个由207名肥胖成年人和177名非肥胖成年人组成的便利样本中，对血红素铁和非血红素铁的摄入量以及其他已知会影响铁吸收的饮食因素的摄入量进行了横断面比较。在21个月的时间里，受试者完成了7天的饮食记录，接受了静脉穿刺以测量血清铁，并通过双能X线吸收法评估了身体成分。数据采用协方差分析和多元线性回归进行分析。肥胖个体的血清铁（均值±标准差）显著低于非肥胖个体（72.0±61.7 vs 85.3±58.1μg/dL [12.888±11.0443 vs 15.2687±10.3999μmol/L]；P<0.001）。肥胖队列报告摄入的动物蛋白更多（63.6±34.5 vs 55.7±32.5g/天；P<0.001），血红素铁更多（3.6±2.8 vs 2.7±2.6mg/天；P<0.001）。然而，两组在包括补充剂在内的每日总铁摄入量方面没有差异。肥胖受试者报告摄入的维生素C较少（77.2±94.9 vs 91.8±89.5mg/天；P=0.01），维生素C可能会增加非血红素铁的吸收，以及钙较少（766.2±665.0 vs 849.0±627.2mg/天；P=0.038），钙可能会减少非血红素铁的吸收，均低于非肥胖受试者。两组在其他可能影响铁吸收的饮食因素的摄入量方面没有显著差异，这些因素包括植酸、草酸、鸡蛋、咖啡、茶、锌、植物蛋白或铜。在考虑了人口统计学协变量和预期会影响铁吸收的饮食因素后，脂肪量（P=0.007）仍然是血清铁的一个具有统计学意义的负预测因子。这项横断面探索性研究表明，肥胖相关的低铁血症与报告的血红素铁和非血红素铁摄入量或可能影响铁吸收的饮食因素的差异无关。
