Dietary Factors Affecting Calcium and Zinc Absorption

影响钙和锌吸收的饮食因素

• 批准号: 6908288
• 负责人: STEVEN A ABRAMS
• 金额: $ 4.1万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-06-01 至 2007-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6908288
• 关键词: Africa; African; African American; United States; clinical research; developmental nutrition; diet; diet therapy; dietary calcium; dietary supplements; gastrointestinal nutrient absorption; geographic difference; grain; human subject; human therapy evaluation; inositol phosphates; malabsorption; mass spectrometry; middle childhood (6-11); nutrient interaction; nutrition related tag; patient oriented research; preschool child (1-5); rickets; vitamin D; zinc

DESCRIPTION (provided by applicant) We have conducted a series of studies to evaluate calcium and bone mineral status in children. Subsequent to our competitive renewal in 2001, we are beginning the 8th year of our studies to evaluate methods of improving bone mineralization in children. Our goal is to identify dietary factors to enhance calcium absorption and bone mineralization in vulnerable populations. We use stable isotope methods that are safe and applicable globally to assess mineral metabolism (calcium, zinc, magnesium, iron, copper). We propose to extend our research to evaluate dietary antecedents of mineral deficiency in a unique population of children with severe calcium deficiency-related rickets in Nigeria. We propose to develop a novel collaboration for conducting comprehensive mineral research. Hypotheses: Our overall hypotheses are that clinical and radiological signs of rickets in Nigeria are primarily related to dietary mineral insufficiency, especially in the presence of dietary inhibitors of mineral absorption. Therefore, enhanced mineral absorption should be possible by decreasing the effects of these inhibitors. Although calcium is the most important bone mineral, it is well recognized that other minerals, including zinc, are crucial for growth and bone mineralization. Inadequate zinc status may contribute to slow overall growth which may be a particular problem in Nigeria due to the high phytate content of the diets. It may be optimal, therefore, to provide mineral supplementation to children receiving typical Nigerian meals or to reduce the phytate contents of the meal. Specifically, we hypothesize that; 1) Supplemental calcium and zinc will be absorbed significantly better when given without a meal than when given with a typical Nigerian meal; 2) Dephytinization of a typical meal will enhance calcium and zinc absorption. Study Methods: We will enroll 18 children age 2-8 yrs with clinical and biochemical evidence of rickets and 18 age- and gender-matched healthy, children in Jos, Nigeria. Children will receive therapy with calcium and vitamin D for 6 weeks prior to measurement of mineral absorption. A multiple stable isotope method will be used to compare calcium and zinc absorption from 250 mg calcium and 10 mg zinc given with and without a typical Nigerian meal. One week later, the study will be repeated evaluating the effects of dephytinization on mineral absorption. At that time, the subjects will be randomized to receive one of two different popular weaning foods. Absorption from these foods will be measured both with and without dephytinization prior to the meal. After the studies, children with rickets will receive clinical treatment for their disease. Conclusions: We hypothesize that dephytinization will lead to markedly improved calcium and zinc absorption. Fractional absorption of calcium and zinc after dephytinization will be similar to that from supplementation given without a meal. This may be important in developing strategies for mineral supplementation in Nigeria. Key technologies including stable isotope absorption techniques and methods for measuring PTH and 25(OH)D concentrations will be transferred to the Nigerian research team. There are no other research centers in Africa with the capacities to conduct such studies and the ability to prepare samples for mass spectrometric analysis of multiple minerals. Comparisons of calcium and zinc absorption will be possible between children in Nigeria and age and gender-matched African-American children living in Houston, TX. Training programs in the US and Nigeria will enable further studies of mineral requirements, including calcium and zinc kinetic measurements to be conducted in Nigeria.

描述（由申请人提供） 我们已经进行了一系列研究，以评估儿童的钙和骨矿物质状态。在2001年我们的竞争性更新之后，我们开始研究第8年，以评估改善儿童骨矿化的方法。我们的目标是确定饮食因素，以增强脆弱人群的钙吸收和骨矿化。我们使用稳定的同位素方法，可安全且适用于全球评估矿物质代谢（钙，锌，镁，铁，铜）。我们建议扩展我们的研究，以评估尼日利亚与钙缺乏症相关的严重缺乏症的独特儿童中矿物质缺乏症的饮食前提。我们建议开发一种用于进行全面矿物研究的新型合作。假设：我们的总体假设是尼日利亚rick鼠的临床和放射学迹象主要与饮食中的矿物质不足有关，尤其是在存在矿物质吸收的饮食抑制剂的情况下。因此，应通过降低这些抑制剂的作用来增加矿物质吸收。尽管钙是最重要的骨矿物质，但人们众所周知，包括锌在内的其他矿物质对于生长和骨矿化至关重要。锌状态不足可能导致整体增长缓慢，这可能是尼日利亚的一个特殊问题，这是由于饮食中植物的含量高。因此，为接受典型尼日利亚餐食的儿童提供矿物质补充或减少餐食的植物含量可能是最佳的。具体来说，我们假设了这一点。 1）与典型的尼日利亚餐食相比，不用餐食时，补充钙和锌的吸收将明显好； 2）典型餐食的脱脂化将增强钙和锌的吸收。研究方法：我们将在尼日利亚乔斯（Jos）招募18岁2 - 8岁的儿童，有rick子和18岁和性别匹配的健康儿童的临床和生化证据。在测量矿物质吸收之前，儿童将接受钙和维生素D的治疗6周。将使用多种稳定的同位素方法比较有和没有典型的尼日利亚餐的250 mg钙和10 mg锌的钙和锌吸收。一周后，将重复评估脱脂化对矿物质吸收的影响。当时，受试者将被随机接收两种流行的断奶食品之一。这些食物的吸收将在进餐前以有或不进行脱脂化测量。研究后，有rick子的儿童将接受疾病的临床治疗。结论：我们假设脱脂化将显着改善钙和锌的吸收。脱流化后钙和锌的分数吸收与不饮食中的补充相似。这对于制定尼日利亚矿产补充策略可能很重要。关键技术包括稳定的同位素吸收技术和测量PTH和25（OH）D浓度的方法，将转移到尼日利亚研究团队。非洲没有其他研究中心具有进行此类研究的能力以及准备样品进行多种矿物质的质谱分析的能力。尼日利亚儿童以及居住在德克萨斯州休斯顿的儿童以及与性别匹配的非裔美国人儿童之间的钙和锌吸收的比较。美国和尼日利亚的培训计划将进一步研究矿物质需求，包括在尼日利亚进行的钙和锌动力学测量。