健康孕妇在妊娠晚期的赖氨酸需求量高于妊娠早期。

Lysine Requirements of Healthy Pregnant Women are Higher During Late Stages of Gestation Compared to Early Gestation.

机构信息

BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.

Pediatrics, Obstetrics and Gynecology, and School of Population and Public Health, University of British Columbia, British Columbia, Canada.

出版信息

J Nutr. 2018 Jan 1;148(1):94-99. doi: 10.1093/jn/nxx034.

DOI:10.1093/jn/nxx034

PMID:29378056

Abstract

BACKGROUND

Lysine is the first limiting amino acid in cereal proteins and is found mainly in animal-derived products. Current Dietary Reference Intake (DRI) recommendations extrapolate lysine requirements during pregnancy from nonpregnant adult data, and may underestimate true requirements.

OBJECTIVE

Our objective is to define a quantitative lysine requirement in healthy pregnant women and to determine whether requirements vary between 2 phases of gestation.

METHODS

Fourteen pregnant women in early (12-19 wk) and 19 women in late (33-39 wk) gestation were studied using the indicator amino acid oxidation technique. Individual lysine intakes (6-84 mg · kg-1 · d-1, deficient to excess) were tested on each study day as a crystalline amino acid mixture based on egg protein composition. Isonitrogenous diets maintained protein intake at 1.5 g · kg-1 · d-1 and calorie intake at 1.7 times resting energy expenditure during each study day. Phenylalanine and tyrosine intakes were held constant across all lysine intakes. Breath and urine samples were collected at baseline and isotopic steady state. Lysine requirements were determined by measuring the oxidation of L-[1-13C]-phenylalanine to 13CO2 (F13CO2). Biphase linear regression crossover analysis was used to determine a breakpoint (which represents the estimated average requirement, EAR) in F13CO2.

RESULTS

The EAR for lysine during early gestation was determined to be 36.6 mg · kg-1 · d-1 (R2 = 0.484, upper 95% CI = 46.2 mg · kg-1 · d-1), similar to an earlier adult requirement of 36 mg · kg-1 · d-1. The EAR for lysine during late gestation was determined to be 50.3 mg · kg-1 · d-1 (R2 = 0.664, upper 95% CI = 60.4 mg · kg-1 · d-1), 23% higher than the current pregnancy DRI EAR recommendation of 41 mg · kg-1 · d-1.

CONCLUSIONS

Our results suggest that lysine requirements are higher during late gestation compared to early gestation, and that current dietary lysine recommendations during late stages of pregnancy may be underestimated. The results have implications for populations consuming cereal-based diets as their primary source of protein. This trial was registered at clinicaltrials.gov as NCT01776931.

摘要

背景

赖氨酸是谷物蛋白中的第一限制氨基酸，主要存在于动物源性产品中。目前的膳食参考摄入量 (DRI) 建议从非孕妇的成人数据中推断孕妇在怀孕期间的赖氨酸需求量，这可能会低估实际需求量。

目的

我们的目的是确定健康孕妇的定量赖氨酸需求，并确定需求是否在妊娠的两个阶段之间存在差异。

方法

对 14 名处于早期妊娠（12-19 周）和 19 名处于晚期妊娠（33-39 周）的孕妇使用指示剂氨基酸氧化技术进行研究。在每个研究日，根据鸡蛋蛋白组成，作为结晶氨基酸混合物，测试个体赖氨酸摄入量（6-84mg·kg-1·d-1，不足到过量）。在每个研究日，等氮饮食将蛋白质摄入量维持在 1.5g·kg-1·d-1，热量摄入量维持在休息能量消耗的 1.7 倍。在所有赖氨酸摄入量下，苯丙氨酸和酪氨酸的摄入量保持不变。在基线和同位素稳定状态时收集呼吸和尿液样本。通过测量 L-[1-13C]-苯丙氨酸氧化为 13CO2（F13CO2）来确定赖氨酸需求。使用双相线性回归交叉分析来确定 F13CO2 中的断点（代表估计平均需求量 EAR）。

结果

早期妊娠赖氨酸的 EAR 确定为 36.6mg·kg-1·d-1（R2=0.484，上限 95%CI=46.2mg·kg-1·d-1），与之前成年人的 36mg·kg-1·d-1 需求相似。晚期妊娠赖氨酸的 EAR 确定为 50.3mg·kg-1·d-1（R2=0.664，上限 95%CI=60.4mg·kg-1·d-1），比当前妊娠 DRI EAR 推荐值 41mg·kg-1·d-1 高 23%。