DIETARY MINERAL BIOAVAILABILITY IN PREMATURE INFANTS

宫内生长速度已成为产后的标准 比较了早产儿的生长发育，并对早产儿的体成分进行了分析 足月儿已成为营养需求的标准 都是经过计算的。对早产儿进行代谢平衡研究 以确定婴儿是否保留了膳食营养素的量 每单位时间的身体与该营养物质在子宫内的积累相匹配 在相当的一段时间内，通常表现为阴性 营养平衡，并建议在以下情况下营养物质的身体缺陷 学习。这尤其是在矿物方面的经验，如 钙、锌和铜。此外，由于技术上的困难， 既可以低估也可以高估吸收和保留， 代谢平衡研究产生不同的结果。因此在这件事上 我们建议直接测量膳食的生物利用度 稳定同位素早产儿的钙、锌、铜 浓缩技术。60名适合胎龄的婴儿， 出生体重小于或等于1,500克，耐受完全肠道 到7日龄，每天至少100大卡/公斤的营养将构成最终的 研究人口。这些婴儿将被分成3个喂养组 20.第一组将收到一个专有配方，该配方是专门为 为成长中的早产儿设计的第二组将收到他们自己的 母乳(PTHM)，第三组将接受强化的PTHM(一种混合物 用自己母亲的PTHM和矿物质粉末补充剂)。十 每组婴儿的出生体重将低于1,250克(亚组 A)和10个婴儿的出生体重将在1,250到1,500克之间(B亚组)。 钙、锌和铜的生物可利用性将通过添加 含有示踪量的稳定的、非放射性的、 这些矿物的天然同位素46Ca、70Zn和65Cuto 一次喂养，然后72小时收集大便和尿液。同位素 对粪便和尿液样本的矿物质分析将允许 准确计算各给药药物的吸收分数 稳定的同位素。将分别进行两项生物利用度研究 婴儿；第一个在10天到14天之间，第二个在身体上 A亚组婴儿的体重约为1500克，约为1750克 因此，这项研究将确定对B亚组婴儿的影响 出生后年龄对饮食中钙、锌和铜的生物利用率的影响 同时比较它们在PTHM、配方奶粉和 防御型PTHM。

The intrauterine growth rate has become the standard to which postnatal growth of premature infants is compared, and the body composition of the full-term infant has become the standard from which nutrient requirements have been calculated. Metabolic balance studies, performed with premature infants to determine whether the amount of the dietary nutrient retained by the body per unit time matched the in utero accumulation of that nutrient over an equivalent period of time, have often demonstrated negative nutrient balances and have suggested body deficits of the nutrient under study. This has been particularly the experience with minerals such as calcium, zinc, and copper. Furthermore, due to technical difficulties that can either underestimate or overestimate both absorption and retention, metabolic balance studies produce variable results. Therefore in this investigation we propose to directly measure the bioavailability of dietary calcium, zinc, and copper in premature infants with stable isotope enrichment technology. Sixty appropriate for gestational age infants with birthweights less than or equal to 1,500 gm that tolerate full enteral nutrition of at least 100 kcal/kg/day by 7 days of age will form the final study population. These infants will be divided into 3 feeding groups of 20. Group I will receive a proprietary formula that has been specifically designed for the growing premature infant, Group II will receive their own mother's milk (PTHM), and Group III will receive fortified-PTHM (a mixture of their own mother's PTHM with a powdered mineral supplement). Ten infants in each group will have a birthweight less than 1,250 gm (Subgroup A) and 10 will have a birthweight between 1,250 and 1,500 gm (Subgroup B). Calcium, zinc, and copper bioavailability will be assessed by the addition of a solution containing tracer amounts of stable, non-radioactive, naturally occurring isotopes of those minerals, 46Ca, 70Zn, and 65Cu, to one feeding, followed by a 72 hour collection of stool and urine. Isotopic and mineral analyses of the stool and urine samples will then permit an accurate calculation of the fractional absorption of each administered stable isotope. Two bioavailability studies will be performed with each infant; the first between 10 and 14 days of age and the second at a body weight of about 1,500 gm for the infants in Subgroup A and about 1,750 gm for the infants in Subgroup B. Thus, this study will determine the effect of post-natal age on dietary calcium, zinc, and copper bioavailability, while comparing their bioavailability from PTHM, formula, and fortified-PTHM.