Dietary Factors Affecting Calcium and Zinc Absorption

影响钙和锌吸收的饮食因素

• 批准号: 7090028
• 负责人: STEVEN A ABRAMS
• 金额: $ 4万
• 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 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7090028
• 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） 我们进行了一系列研究来评估儿童的钙和骨矿物质状况。继 2001 年进行竞争更新之后，我们开始了第八年的研究，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弱势群体的钙吸收和骨矿化。我们使用安全且适用于全球的稳定同位素方法来评估矿物质代谢（钙、锌、镁、铁、铜）。我们建议扩大我们的研究范围，以评估尼日利亚患有严重缺钙相关佝偻病的独特儿童群体中矿物质缺乏的饮食因素。我们建议开展新的合作来进行全面的矿物研究。假设：我们的总体假设是，尼日利亚佝偻病的临床和放射学症状主要与膳食矿物质不足有关，特别是在存在矿物质吸收膳食抑制剂的情况下。因此，通过降低这些抑制剂的作用应该可以增强矿物质的吸收。尽管钙是最重要的骨矿物质，但众所周知，包括锌在内的其他矿物质对于生长和骨矿化也至关重要。锌含量不足可能会导致整体生长缓慢，由于饮食中植酸含量较高，这在尼日利亚可能是一个特殊问题。因此，最好为接受典型尼日利亚膳食的儿童提供矿物质补充剂或减少膳食中的植酸含量。具体来说，我们假设； 1) 与典型的尼日利亚膳食相比，不进餐时补充钙和锌的吸收效果明显更好； 2) 典型膳食的脱植碱将增强钙和锌的吸收。研究方法：我们将在尼日利亚乔斯招募 18 名具有佝偻病临床和生化证据的 2-8 岁儿童以及 18 名年龄和性别匹配的健康儿童。在测量矿物质吸收之前，儿童将接受为期 6 周的钙和维生素 D 治疗。将使用多重稳定同位素方法来比较含或不含典型尼日利亚膳食的 250 毫克钙和 10 毫克锌的钙和锌吸收情况。一周后，该研究将重复评估脱植素对矿物质吸收的影响。届时，受试者将被随机接受两种不同的流行断奶食品中的一种。将在餐前测量有或没有脱植碱的情况下这些食物的吸收情况。研究结束后，患有佝偻病的儿童将接受针对其疾病的临床治疗。结论：我们假设脱植碱将显着改善钙和锌的吸收。脱植碱后钙和锌的吸收分数与不进餐补充的钙和锌吸收分数相似。这对于制定尼日利亚矿物质补充战略可能很重要。稳定同位素吸收技术、PTH和25(OH)D浓度测量方法等关键技术将转让给尼日利亚研究团队。非洲没有其他研究中心有能力进行此类研究，也没有能力制备用于多种矿物质谱分析的样品。尼日利亚儿童与居住在德克萨斯州休斯顿的年龄和性别匹配的非裔美国儿童之间的钙和锌吸收情况的比较是可能的。美国和尼日利亚的培训计划将有助于进一步研究矿物质需求，包括在尼日利亚进行钙和锌动力学测量。