Johnson J M, Walker P M
Department of Home Economics, Illinois State University, Normal 61761.
J Am Diet Assoc. 1992 Dec;92(12):1474-8.
The purpose of this study was to determine the utilization of zinc in young adult women fed diets containing varying amounts of lean ground beef. A secondary objective was to determine the utilization of iron. The 28-day study was divided into one 7-day preexperimental period, during which a vegetarian diet was fed, and three randomly arranged 7-day experimental periods. During the experimental periods, the diets contained 3, 6, or 9 oz of beef, supplying varying levels of zinc and iron. Complete collections of urine and fecal samples were obtained from each subject. All the diets resulted in positive zinc balance; however, mean zinc balances were significantly higher when subjects consumed the experimental diets containing beef. When data for all diets containing beef were combined, mean values for apparent zinc absorption and zinc retention were not significantly higher than values that resulted from the vegetarian diet. Consumption of all diets resulted in a positive iron balance; however, mean iron balances were significantly higher for diets containing beef. As the amount of beef in the diet increased, the bioavailability of iron increased. We found that zinc and iron utilization was enhanced after consumption of a diet including lean ground beef. Results of this study also suggest that little increase in zinc and iron utilization is realized by including more than 3 oz beef per day in the diet.
本研究的目的是确定食用含不同量瘦牛肉末饮食的年轻成年女性对锌的利用率。次要目标是确定铁的利用率。这项为期28天的研究分为一个为期7天的预实验期，在此期间喂食素食，以及三个随机安排的为期7天的实验期。在实验期内，饮食中含有3、6或9盎司牛肉，提供不同水平的锌和铁。从每个受试者处收集完整的尿液和粪便样本。所有饮食都导致锌平衡为正；然而，当受试者食用含牛肉的实验饮食时，平均锌平衡显著更高。当将所有含牛肉饮食的数据合并时，表观锌吸收和锌保留的平均值并不显著高于素食饮食所产生的值。食用所有饮食都导致铁平衡为正；然而，含牛肉饮食的平均铁平衡显著更高。随着饮食中牛肉量的增加，铁的生物利用度增加。我们发现，食用含瘦牛肉末的饮食后，锌和铁的利用率提高。本研究结果还表明，饮食中每天包含超过3盎司牛肉时，锌和铁利用率的增加很少。
