- 期刊
Examination of Chinese Habitual Dietary Protein Requirements of Chinese Young Female Adults by an Indicator Amino Acid Method
以指標氨基酸氧化法确定中国青年女性对日常膳食蛋白质的需要量
摘要
目的：采用指標氨基酸氧化技术，确定中国青年女性对中国日常膳食蛋白质的需要量。方法：通过问卷调查、体格检查和筛选，選擇20名健康女性作为受试者，平均年龄21.6（±0.9）岁。整个实验共3个连续的实验周期，每周期7天。实验膳食为中国日常混合膳食，优质蛋白占40%－45%，共6个膳食蛋白质摄入水平(0.70、0.78、0.86、0.94、1.02和 1.10 g/kg．d)。受试者被随机平均分为2组，每组受试者在每个实验周期摄入1个蛋白质水平的实验膳食，3个周期依次为：第一组：1.10、0.86、0.78 g/kg．d；第二组：1.02、0.94、0.70 g/kg．d。每个实验周期的第1 到6天为适应期，第7天为同位素实验日。在受试者的非月经期，应用指標氨基酸氧化法进行氨基酸代谢动力学的研究。将实验所得的13CO2产生率、亮氨酸（leucine）氧化率两个指标，分别代入兩相回归曲线模型，确定回归曲线的拐点，即蛋白质的生理需要量。结果：通过13CO2产生率计算的中国青年女性非月经期对中国日常混合膳食蛋白质的平均需要量是0.91g/kg．d，人群安全需要量是1.09 g/kg．d；通过亮氨酸氧化率计算的平均需要量是0.92 g/kg．d，人群安全需要量是1.10 g/kg．d。结论：中国青年女性在非月经期对日常膳食蛋白质的需要量低于目前的膳食推荐摄入量。女性在整个月经周期中的膳食蛋白质需要量，尚需进一步研究探讨。
並列摘要
Objective: To determine protein requirement of Chinese young female adults on habitual Chinese diet through indicator amino acid oxidation (IAAO) technique. Design: Twenty women with a mean (SD) age of 21.6 (0.9) years were healthy based on questionnaire, physical examinations and screening tests. There were three consecutive periods of 7 days each with six different intakes of protein (0.70, 0.78, 0.86, 0.94, 1.02 and 1.10 g/kg．d) within Chinese habitual diets (proportions of good-quality protein were 40 to 45%). Subjects were randomly allocated equally into two groups (1.10, 0.86, 0.78 g/kg．d for group 1 and 1.02, 0.94, 0.70 g/kg．d for group 2 from period 1 to period 3 in turn). Adaptation days were from day 1 to day 6 and the isotope study day was day 7 in each period. Amino acid kinetics was measured in non-menstrual periods, based on the IAAO technique. Two indicators (rate of release of 13CO2 and rate of leucine oxidation) were used to estimate protein requirement by breakpoint analysis with a two-phase linear regression crossover model. Results: Mean and population safe protein requirements of Chinese habitual diets in non-menstrual periods from the rate of release of 13CO2 were 0.91 and 1.09 g/kg．d, respectively. And from the rate of leucine oxidation were 0.92 and 1.10 g/kg．d, respectively. Conclusions: The protein requirement of young women on Chinese habitual diets in non-menstrual period was lower than the current protein reference intake for Chinese females. Further studies are necessary to explore female protein requirements during the whole menstrual cycle.