Determination of Pre-Absorptive Dissociation of Zinc From a Zinc Amino Acid Complex in Healthy Men
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 13
- 试验地点
- 2
- 主要终点
- Zinc Transport Curve
研究概览
简要总结
Zinc may be absorbed from diet via zinc transporter mediated pathways, or, when coupled with amino acids, via amino acid transporter pathways. When zinc is coupled with amino acids in diet, it may dissociate from those amino acids in the acidic environment of the stomach prior to entering the small intestine. An experimentally-determined value for any pre-absorptive dissociation of zinc from a zinc amino acid complex (ZnAA) is necessary for the accurate compartmental modeling of zinc metabolism when provided as ZnAA compared with ionic zinc, which the investigators will perform in a future study. The current study will allow us to determine the dissociation of zinc from ZnAA, while serving as a pilot test of a novel technique to determine for the first time an individual's zinc transport kinetics.
详细描述
An experimentally-determined value for any pre-absorptive dissociation of zinc from ZnAA is necessary for the accurate compartmental modeling of zinc metabolism when provided as ZnAA compared with zinc chloride, which the investigators will perform in a future study.
The current study will allow us to determine the pre-absorptive dissociation of zinc from ZnAA, while serving as a pilot test of a novel technique to determine for the first time an individual's zinc transport kinetics. Since zinc absorption kinetics follow a saturable process, the zinc transport maximum (Tr_max) and transport rate (K_Tr) can be determined by fitting Hill transport equation to measurements of absorbed zinc at 3 or more levels of zinc intake (mg zinc/d):
Total Absorbed Zinc (TAZ) = (Zinc Intake * Tr_max) / (Zinc Intake + K_Tr)
Although population data have been used to estimate zinc transport kinetics (Tran, et al. AJCN 2004), Tr_max and K_tr have never been determined in individual subjects. The investigators plan to determine the fractional zinc absorption (FZA) from multiple levels of dietary zinc in rapid succession (Chung, et al. AJCN 2004) and, therefore, estimate an individual's transport maximum and rate, Tr_max and K_Tr. Once Tr_max and K_Tr are known, the FZA can be used to determine an unknown zinc intake from zinc chloride and any zinc dissociated from the ZnAA complex using the following equation:
Zinc Intake = (Tr_max / FZA) - K_Tr
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- None
盲法说明
Subjects are not informed of the amount of zinc in each test diet, or the order of the diets. The basic foods making up the test diets are identical in appearance and amount on each of the oral zinc stable isotope tracer days, so there is no way for the subject to distinguish any differences in the amount or form of zinc given.
入排标准
- 年龄范围
- 18 Years 至 50 Years（Adult）
- 性别
- Male
- 接受健康志愿者
- 是
入选标准
- •Apparently healthy men
- •Body mass index between 18 and 30 kg/m2
- •Willing to eat only the foods provided by the study for a 2 week period
排除标准
- •Those reporting any chronic or acute diseases, food allergies, smoking or alcohol abuse
- •Use of illicit drugs; regular consumption of medications, micronutrient supplements, or both
- •Vegetarians, or those unable to eat meat, are also excluded since the foods for the study contain meat
- •Unable to refrain from taking medications during the study period
结局指标
主要结局
Zinc Transport Curve
时间窗: 2 weeks
The saturable zinc transport curve determined by fitting the zinc absorption data to the Hill transport equation
Dissociated Amino Acid Zinc
时间窗: 2 weeks
Amount of zinc dissociated from the ZnAA prior to absorption
次要结局
未报告次要终点