Kunkel M E, Beauchene R E
Department of Nutrition and Food Sciences, College of Home Economics, University of Tennesse, Knoxville 37996-1900.
J Am Coll Nutr. 1991 Aug;10(4):308-14. doi: 10.1080/07315724.1991.10718157.
Relationships among age, protein intake, and urinary excretion of protein-derived metabolites were studied in 125 vegetarian and nonvegetarian women ages 40-92. There were 63 women in the vegetarian (AV) group and 62 women in the nonvegetarian (NV) group. Average daily intakes of energy and total animal and vegetable protein were calculated from 7-day dietary records. Twenty-four-hour urine samples were analyzed for total nitrogen, urea, creatinine, hydroxyproline, and inorganic sulfate. Energy intakes for the two groups were similar. AVs consumed less total and animal protein and more vegetable protein than NVs, even though both groups consumed more than the RDA for protein. No significant differences existed between the groups in the urinary excretion of total nitrogen, urea nitrogen, hydroxyproline, or inorganic sulfate. Energy and protein intakes and total nitrogen excretion were lower in older AVs than in younger AVs, while those of NVs increased between 40 and 55 years of age, and decreased among the older NV women. The relationship between these variables and age in NVs was more accurately described by polynomial rather than linear regression models.
在125名年龄在40至92岁之间的素食和非素食女性中，研究了年龄、蛋白质摄入量与蛋白质衍生代谢物尿排泄之间的关系。素食（AV）组有63名女性，非素食（NV）组有62名女性。根据7天的饮食记录计算能量以及动物蛋白和植物蛋白的日均摄入量。对24小时尿液样本进行总氮、尿素、肌酐、羟脯氨酸和无机硫酸盐分析。两组的能量摄入量相似。尽管两组的蛋白质摄入量均超过了推荐膳食摄入量（RDA），但与非素食者相比，素食者摄入的总蛋白和动物蛋白较少，植物蛋白较多。两组之间在总氮、尿素氮、羟脯氨酸或无机硫酸盐的尿排泄方面不存在显著差异。年龄较大的素食者的能量和蛋白质摄入量以及总氮排泄量低于较年轻的素食者，而非素食者的能量和蛋白质摄入量以及总氮排泄量在40至55岁之间增加，在年龄较大的非素食女性中减少。用多项式而非线性回归模型能更准确地描述非素食者中这些变量与年龄之间的关系。
