Determining Dietary Tryptophan Requirements In Healthy Pregnant Women Using The Indicator Amino Acid Oxidation Method
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 29
- 试验地点
- 2
- 主要终点
- Carbon 13 Oxidation
研究概览
简要总结
Pregnancy is an important period of life where there is an increased need for nutrients including protein and amino acids from food. The current protein and amino acids dietary recommendations were all established using older methods done in adult men. Then protein and amino acids requirements for all stages of pregnancy were calculated without accounting for changing demands in each trimester. Therefore, another more precise method is needed to better understand how much amino acids (in this study tryptophan) women need during pregnancy.
In the current study, the investigators are going to apply the Indicator Amino Acid Oxidation (IAAO) method to measure the dietary tryptophan needs in a healthy pregnancy. This method is a noninvasive, quick, and reliable technique that uses a stable isotope-labeled amino acid. The stable isotope tracer is a labeled amino acid, which is colorless, odorless, tasteless, and completely safe; they are present in the air, water and food. Amino acids are mostly made of Carbon-12 (12C), whereas the isotope tracer contains Carbon-13 (13C). The tracer can be detected in breath and urine samples with special equipment because it looks different than the rest of the amino acids in the body. In Elango lab, the investigators have done similar studies, using the same technique in children, nonpregnant women and pregnant women. This will allow us to measure tryptophan needs in pregnancy.
详细描述
Pre-Study:
All participants will arrive following a 10-12 hrs overnight fasting, to allow the anthropometric measurements, biochemical, and dietary assessments. Fasting blood glucose by finger prick will be used to screen for gestational diabetes. The presence of protein, glucose, ketones, leukocytes, and blood in urine will be assessed using urinalysis strips as potential indicators of gestational diabetes and preeclampsia. For the anthropometric assessment, weight and height will be measured and body composition will be determined using skinfold thickness measurements and Bioelectrical Impedance Analysis (BIA). A brief medical history will be obtained to screen for medication use, substance use, previous pregnancies, and overall health. For the dietary assessment, energy requirements will be determined using Resting Energy Expenditure (REE) by continuous, open-circuit indirect calorimetry. In addition to two-days detailed dietary records to estimate participants' calorie, protein, and tryptophan intake.
Study Day:
Participants are expected to arrive following a 10-12 hrs overnight fasting, as mentioned above, anthropometric measurements, fasting blood glucose testing and urine strip analysis will be repeated at the beginning of each study day. On the study day, the investigator will randomly assign the participant a test tryptophan intake (ranging between 1 to 14 mg.kg.d) and will receive an 8-hourly isocaloric and isonitrogenous meal. Based on Resting Energy Expenditure determined during the pre-study day, each meal will provide daily adequate energy and adequate protein (at 1.5 g.kg.d) to ensure that the Indicator Amino Acid Oxidation (IAAO) response is due to the different test tryptophan intakes and not from the limited energy and/or protein. During the study days, participants will be allowed to have the prepared study diets and water only.
Sample Collection:
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
入排标准
- 年龄范围
- 20 Years 至 40 Years（Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •Cis-gendered pregnant woman.
- •20-40 years of age.
- •Pregnant with a single child.
- •Between 11-20 weeks of gestation or 31-40 weeks of gestation.
- •Free of chronic diseases/acute diseases and have a full range of physical mobility.
排除标准
- •Women who are not pregnant.
- •Women who are pregnant with more than one child (this changes amino acid demands) or were pregnant in the 6 months before the current pregnancy.
- •Women with a history of spontaneous abortion (within the last 6 months) or preterm birth.
- •Women not in good health or have a metabolic, cardiovascular, neurological, genetic, or immune disorder, including gestational diabetes, preeclampsia, pregnancy-related anemia, or pregnancy-related jaundice.
- •Claustrophobic women (a clear hood will be placed, which can easily be removed, over the participants head for approximately 20 min to measure energy expenditure).
- •Women who are substance dependent (i.e., alcohol, tobacco, illicit drugs).
- •Women who have severe nausea/vomiting throughout their pregnancy.
- •Women under the age of 20 years and over the age of 40 years.
- •Women who have lost weight (approximately 1.5kg or more) during their current pregnancy.
- •Women with a pre-pregnancy Body Mass Index (BMI) under 19 or over 28 〖kg/m〗^2.
结局指标
主要结局
Carbon 13 Oxidation
时间窗: 8 hours
Urine and breath will be collected to measure the rate of oxidation of L-\[1-13C\]phenylalanine oxidation.
次要结局
未报告次要终点
研究者
Rajavel Elango, PhD
Principal Investigator
University of British Columbia