Basal urinary zinc/creatinine ratio as an indicator of dietary zinc intake in healthy adult women.

Objective: To study, in healthy women, the correlation between the basal urinary zinc/creatinine ratio and dietary zinc intake.
Subjects: A group of 36 healthy female University students was evaluated. Mean age and body weight were, respectively, 25.6+/-3.3 years and 54.4+/-7.0 kg.
Methods: Basal urine was collected; Zn was determined by AAS and Creatinine (Creat) by the Jaffe method. A nutritional survey of seven days was recorded. Mean daily dietary intake of energy (DE) and zinc (DZn) were calculated according to the INCAP and English or German Food Composition Tables, respectively.
Results: Mean dietary daily intake were as follows (x +/- SD): Energy (kcal): 1606+/-570; zinc (mg): 9.1+/-3.8; basal urine Zn/Creat ratio: 0.41+/-0.24. Individual values of the Zn/Creat ratio correlated with dietary Zn (r=0.481, p=0.0339); data grouped according to ranges of dietary Zn fit the following equation: Zn/Creat=0.160+/-0.034 DZn (mg/day); (r=0.870, p=0.00497).
Conclusions: These results showed that the basal urinary Zn/Creat ratio could be a useful indicator of dietary Zn intake in healthy adult women.