Tul-Noor Zujaja, Paoletti Alyssa, Fakiha Abrar, Pencharz Paul B, Levesque Crystal L, Ball Ronald O, Elango Rajavel, Courtney-Martin Glenda
SickKids Research Institute, Hospital for Sick Children, Toronto, ON, Canada.
SickKids Research Institute, Hospital for Sick Children, Toronto, ON, Canada; Department of Nutritional Sciences, University of Toronto, Toronto, ON, Canada; Department of Paediatrics, University of Toronto, Toronto, ON, Canada.
J Nutr. 2025 Feb;155(2):476-482. doi: 10.1016/j.tjnut.2024.08.011. Epub 2024 Aug 18.
The protein quality of wheat is limited by its low content of the indispensable amino acid (AA) lysine and the metabolic availability (MA) of lysine in wheat bread for humans is unknown.
The study objective was to determine the MA of lysine in whole wheat bread.
Five healthy young males (≤30 y, BMI <25 kg/m) were studied in a repeated-measures design using the indicator amino acid oxidation (IAAO) method, with L-[1-C] phenylalanine as the indicator. Each received 7 levels of lysine intakes in random order; 4 levels of L-lysine; 5, 8, 12, and 15 mg/kg/d (reference diet), and 3 intakes of lysine from whole wheat bread (test diet). The MA of lysine in whole wheat bread was assessed by comparing the IAAO response to the test diet (whole wheat bread) with the IAAO response to the reference diet using the slope ratio method.
The MA of lysine from whole wheat bread was 90%.
Lysine has a high MA but it is still limiting in whole wheat bread due to its low concentration. A combination of wheat with a complementary protein source (that is, lentils which are sufficient in lysine) is recommended to meet the lysine requirement in a wheat-based diet for healthy young males. This trial was registered at clinicaltrials.gov as NCT03674736 and NCT03200652.
小麦的蛋白质质量受必需氨基酸赖氨酸含量低的限制，且小麦面包中赖氨酸对人体的代谢可用性未知。
本研究旨在测定全麦面包中赖氨酸的代谢可用性。
采用重复测量设计，使用以L-[1-C]苯丙氨酸为指示剂的指示剂氨基酸氧化（IAAO）方法，对5名健康年轻男性（年龄≤30岁，体重指数<25kg/m）进行研究。每人随机接受7种赖氨酸摄入量水平；4种L-赖氨酸水平，即5、8、12和15mg/kg/d（参考饮食），以及3种全麦面包中赖氨酸的摄入量（试验饮食）。通过使用斜率比法比较试验饮食（全麦面包）和参考饮食的IAAO反应，评估全麦面包中赖氨酸的代谢可用性。
全麦面包中赖氨酸的代谢可用性为90%。
赖氨酸具有较高的代谢可用性，但由于其浓度较低，在全麦面包中仍然是限制性的。建议将小麦与补充蛋白质来源（即富含赖氨酸的小扁豆）结合，以满足健康年轻男性以小麦为主的饮食中对赖氨酸的需求。该试验在clinicaltrials.gov上注册，注册号为NCT03674736和NCT03200652。
