Petry Nicolai, Rohner Fabian, Gahutu Jean Bosco, Campion Bruno, Boy Erick, Tugirimana Pierrot L, Zimmerman Michael Bruce, Zwahlen Christian, Wirth James P, Moretti Diego
GroundWork, Crans-près-Céligny, Switzerland;
Department of Medical Biology, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Huye, Rwanda;
J Nutr. 2016 May;146(5):970-5. doi: 10.3945/jn.115.223693. Epub 2016 Mar 30.
Phytic acid (PA) is a major inhibitor of iron bioavailability from beans, and high PA concentrations might limit the positive effect of biofortified beans (BBs) on iron status. Low-phytic acid (lpa) bean varieties could increase iron bioavailability.
We set out to test whether lpa beans provide more bioavailable iron than a BB variety when served as part of a composite meal in a bean-consuming population with low iron status.
Dietary iron absorption from lpa, iron-biofortified, and control beans (CBs) (regular iron and PA concentrations) was compared in 25 nonpregnant young women with low iron status with the use of a multiple-meal crossover design. Iron absorption was measured with stable iron isotopes.
PA concentration in lpa beans was ∼10% of BBs and CBs, and iron concentration in BBs was ∼2- and 1.5-fold compared with CBs and lpa beans, respectively. Fractional iron absorption from lpa beans [8.6% (95% CI: 4.8%, 15.5%)], BBs [7.3% (95% CI: 4.0%, 13.4%)], and CBs [8.0% (95% CI: 4.4%, 14.6%)] did not significantly differ. The total amount of iron absorbed from lpa beans and BBs was 421 μg (95% CI: 234, 756 μg) and 431 μg (95% CI: 237, 786 μg), respectively, and did not significantly differ, but was >50% higher (P < 0.005) than from CBs (278 μg; 95% CI: 150, 499 μg). In our trial, the lpa beans were hard to cook, and their consumption caused transient adverse digestive side effects in ∼95% of participants. Gel electrophoresis analysis showed phytohemagglutinin L (PHA-L) residues in cooked lpa beans.
BBs and lpa beans provided more bioavailable iron than control beans and could reduce dietary iron deficiency. Digestive side effects of lpa beans were likely caused by PHA-L, but it is unclear to what extent the associated digestive problems reduced iron bioavailability. This trial was registered at clinicaltrials.gov as NCT02215278.
植酸（PA）是豆类中铁生物利用率的主要抑制剂，高PA浓度可能会限制生物强化豆类（BBs）对铁状态的积极影响。低植酸（lpa）豆类品种可提高铁的生物利用率。
我们旨在测试在铁状态较低的豆类食用人群中，当lpa豆类作为复合膳食的一部分时，其提供的生物可利用铁是否比BB品种更多。
采用多餐交叉设计，比较了25名铁状态较低的未怀孕年轻女性对lpa豆类、铁生物强化豆类和对照豆类（CBs，常规铁和PA浓度）的膳食铁吸收情况。使用稳定铁同位素测量铁吸收。
lpa豆类中的PA浓度约为BBs和CBs的10%，BBs中的铁浓度分别比CBs和lpa豆类高约2倍和1.5倍。lpa豆类[8.6%（95%CI：4.8%，15.5%）]、BBs[7.3%（95%CI：4.0%，13.4%）]和CBs[8.0%（95%CI：4.4%，14.6%）]的铁吸收分数无显著差异。lpa豆类和BBs吸收的铁总量分别为421μg（95%CI：234，756μg）和431μg（95%CI：237，786μg），无显著差异，但比CBs（278μg；95%CI：150，499μg）高>50%（P<0.005）。在我们的试验中，lpa豆类难以煮熟，约95%的参与者食用后出现短暂的不良消化副作用。凝胶电泳分析显示煮熟的lpa豆类中存在植物血凝素L（PHA-L）残留。
BBs和lpa豆类比对照豆类提供了更多的生物可利用铁，并且可以减少膳食铁缺乏。lpa豆类的消化副作用可能是由PHA-L引起的，但尚不清楚相关的消化问题在多大程度上降低了铁的生物利用率。该试验在clinicaltrials.gov上注册，注册号为NCT02215278。
