Enhancing Dietary Iron and Zinc Bioavailability in Indian Children

描述（由申请人提供）：背景：铁和锌缺乏症经常同时发生，因为损害铁吸收的饮食因素也影响锌的吸收。印度没有推荐的锌每日摄入量。利用铁和锌的稳定同位素，现在可以精确测量铁和锌的吸收。具体目标是（1）测量代表性印度饮食中铁和锌的生物利用度（2）测量通过代表性印度饮食的可行多样化可实现的铁和锌生物利用度的变化（3）以确定可行的饮食调整的耐受性。研究方法：拟议的方案采用交叉设计，研究从寄宿学校选出的13-15.9岁的健康儿童（16名男孩和16名女孩）。将评估基线铁和锌状态。所有儿童将被随机分配接受代表性饮食或多样化饮食。建议的修改是从水果和蔬菜中加入约20 mg抗坏血酸，这些水果和蔬菜将与每餐一起食用。儿童将连续5天喂食标有57 Fe的相应饮食（仅3天，两顿主餐），第4天口服参考剂量58 Fe（含抗坏血酸）。将在基线和第18天采集血样。同时，在第一餐中给予67 Zn，并在同一天静脉注射参考剂量的70 Zn。将从第3天至第6天采集尿液。吸收将通过血红蛋白中铁的57 Fe和58 Fe的相对富集或使用ICP-MS通过尿中锌的67 Zn和70 Zn的相对富集来定量。然后参与者将在第19天按照相同的方案交叉到另一种饮食。将通过使用5点享乐量表向参与者施用感官评价问卷来评估多样化饮食的耐受性，持续6周。成果：该项目将生成青少年铁和锌吸收情况的数据，为确定RDA以及调整饮食作为预防铁和锌缺乏症战略的可行性提供依据。贝勒医学院的稳定同位素实验室与国家营养研究所建立长期合作关系，以评估印度儿童的营养问题，这将是该项目的一项重要成果。 公共卫生相关性：这项研究将提供证据表明，在印度一个非常“高危”的群体，即青少年中，可实现的饮食变化在改善从饮食中吸收的铁和锌量方面具有重要的益处。改善生物可利用矿物质的摄入量对提高印度人口的健康至关重要，因为这将改善男孩和女孩的学习和工作表现。这些好处将导致更大规模的基于人口的研究，并提高对在发展中国家使用营养干预措施改善健康的理解。

DESCRIPTION (provided by applicant): Background: Iron and zinc deficiencies frequently occur together because the dietary factors that impair iron absorption also affect zinc absorption. There is no recommended daily intake for zinc in India. With stable isotopes of iron and zinc it is now possible to measure precisely iron and zinc absorption. The specific objectives are (1) To measure the bioavailability of iron and zinc from a representative Indian diet (2) To measure the change in bioavailability of iron and zinc achievable by feasible diversification of a representative Indian diet (3) to determine the tolerability of the feasible dietary modifications. Methods: The proposed program uses a cross-over design to study healthy children aged 13-15.9 years (16 boys and 16 girls) selected from residential schools. Baseline iron and zinc status will be assessed. All children will be randomly assigned to receive either the representative diet or the diversified diet. The proposed modification is the inclusion of ~ 20 mg ascorbic acid from fruits and vegetables which will be served with each meal. Children will be fed their respective diets for 5 consecutive days labeled with 57Fe (for 3 days only, two main meals) with an oral reference dose of 58Fe (with ascorbic acid) on day 4. Blood samples will be collected at baseline and on day 18. Simultaneously 67Zn will be given with the first meal and a reference dose of 70Zn injected intravenously on the same day. Urine will be collected from day 3 to day 6. Absorption will be quantitated by the relative enrichment of 57Fe and 58Fe in hemoglobin for iron or by 67Zn and 70Zn in urine for zinc using ICP-MS. The participants will then crossover to the other diet on day 19, following the same protocol. Tolerability of the diversified diet will be assessed for 6 weeks by administering a sensory evaluation questionnaire to the participants using a 5-point hedonic scale. Outcomes: This project will generate data on the absorption of iron and zinc in adolescents to provide a basis for determining the RDA's and the feasibility of dietary modification as a strategy to prevent iron and zinc deficiencies. The establishment of a long term collaboration between the stable isotope laboratories at Baylor College of Medicine and the National Institute of Nutrition to evaluate nutritional problems among children in India will be an important outcome of this project. PUBLIC HEALTH RELEVANCE: This study will provide evidence that achievable dietary changes in a very "at-risk" group, adolescents, in India can have important benefits in improving the amount of iron and zinc absorbed from the diet. Improving the intake of bioavailable minerals would be crucial to enhancing the health of the Indian population as it will improve school and work performance in both boys and girls. These benefits will lead to larger population-based studies and an enhanced understanding of using nutritional interventions in developing countries to improve health.