A total of 48 patients (23 females) were screened for eligibility, enrolled and included in two treatment groups. The proportion and characteristics of the participants at the start did not differ between the study groups (Table 1). The mean age was 12.8 4 years with a median of 14 and range from 1 to 18 years (23 children and 25 adolescents). There were 69% of patients in HD (33/48 cases), 10% in CAPD (5/48 cases) and 21% in CT (10/48 cases). The 60.4% of the cases came from the NICH, and 39.6% from the EsSalud. The most common causes of CKD in this series are presented in Table 2. The duration of ZS was 9.3 3.9 months with a median of 11 months and the range was 1-12 months. In both treatments groups, 50% received less than 10 months of ZS and another 50% between 10-12 months of ZS. The participants contributed 324 12-month child-periods of observation (73%) and follow-up anthropometric assessment over the whole study. The 27% (13/48) did not receive Nutrients 2019, 11, 2671 6 of 20 the planned intervention of ZS and abandoned the study after the first anthropometric and biochemical assessment (six of the