Comment on: does zinc supplementation affect inflammatory markers in hemodialysis patients?

Zinc supplementation and immune factors in adults: a systematic review and meta-analysis of randomized clinical trials

PURPOSE

This systematic review and meta-analysis aimed to investigate the effect of zinc supplementation on immune factors in randomized controlled trials.

METHODS

A comprehensive search was done in PubMed, Scopus, Web of Science, Embase, and Cochrane databases up to December 2020. We used standard and weighted mean differences and 95% confidence intervals for net changes in selected parameters of immune responses. Subgroup analysis was used to find heterogeneity.

RESULT

Overall, 35 RCTs comprising 1995 participants were eligible for this meta-analysis. There was a significant reduction of circulating CRP (WMD: -32.4; 95% CI: -44.45 to -19.62, p < 0.001), hs-CRP (WMD: -0.95; 95% CI: -1.01 to -0.89, p < 0.001), Neutrophil levels (SMD: -0.46; 95% CI: -0.90 to -0.01, p = 0.043), following zinc supplementation. CD4 level also increased significantly, (WMD: 1.79; 95% CI: 0.57 to 3, p = 0.004). Zinc supplementation had no significant effect on WBC (SMD: -0.66; 95% CI: -1.67 to 0.36, p = 0.204), lymphocyte (WMD: 1.86; 95% CI: -0.86 to 4.58, p = 0.181), monocyte levels (SMD: -0.16; 95% CI: -0.07 to 0.39, p = 0.167), CD3 (SMD: 0.37; 95% CI: -0.49 to 1.22, p = 0.399).

CONCLUSION

Zinc supplementation decreased the CRP, hs-CRP and TNF-α, IL-6, neutrophil and increased CD3 and CD4 level significantly.

Effects of Zinc Supplementation on Nutritional Status in Children with Chronic Kidney Disease: A Randomized Trial

BACKGROUND

Zinc is an essential micronutrient for human beings and its deficiency affects their normal growth and development.

OBJECTIVE

The main aim was to evaluate the effect of two doses of zinc supplementation (ZS) on the nutritional status in chronic kidney disease (CKD) children.

METHODS

A randomized-trial multicentric study was conducted in 48 CKD (23 females) patients under 18-years-old, for a year. At random, participants took 30 or 15 mg/day of ZS, respectively. Anthropometric measurements and biochemical analysis were performed. Hypozincemia was determined by serum zinc concentration (SZC) using atomic absorption spectrophotometry. The positive or negative change in patients' body mass index (BMI) Z-score, serum albumin, zinc and C-reactive protein (CRP) levels were used to evaluate the effect of ZS.

RESULTS

Mean SZC was normal before and after ZS. Despite ZS, there were no significant changes in serum albumin, zinc and CRP levels. A positive and significant association was observed between SZC and serum albumin before (p = 0.000) and after (p = 0.007) ZS. In both groups of ZS, there was a small but positive and significant change in body mass and normalization in BMI Z-score, hypoalbuminemia, hypozincemia and high CRP, especially with 30 mg/day of ZS.

CONCLUSIONS

Zinc supplementation may be beneficial for nutritional status in children and adolescents with CKD.

Renal formulas pretreated with medications alters the nutrient profile

BACKGROUND

Pretreating renal formulas with medications to lower the potassium and phosphorus content is common in clinical practice; however, the effect of this treatment on other nutrients is relatively unstudied. We examine whether nutrient composition is affected by pretreating renal formulas with sodium polystyrene sulfonate (SPS) suspension and sevelamer carbonate.

METHODS

Fixed medication doses and treatment times were utilized to determine changes in the nutrient composition of Suplena® and Similac® PM 60/40. The effect of simultaneously adding both medications (co-administration) to the formula on the nutrient composition of Suplena® was also evaluated.

RESULTS

Pretreatment of Suplena® with SPS reduced the concentrations of calcium (11-38 %), copper (3-11 %), manganese (3-16 %), phosphorus (0-7 %), potassium (6-34 %), and zinc (5-20 %) and increased those of iron (9-34 %), sodium (89-260 %), and sulfur (19-45 %) and the pH (0.20-0.50 units). Pretreatment of Similac® PM 60/40 with SPS reduced the concentrations of calcium (8-29 %), copper (5-19 %), magnesium (3-26 %), and potassium (33-63 %) and increased those of iron (13-87 %) and sodium (86-247 %) and the pH (0.40-0.81 units). Pretreatment of both formulas with the SPS suspension led to significant increases in the aluminum concentration in both formulas (507-3957 %). No differences in potassium concentration were observed between treatment times. Unexpectedly, the levels of neither phosphorus nor potassium were effectively reduced in Suplena® pretreated with sevelamer carbonate alone or when co-administered with SPS.

CONCLUSIONS

Pretreating formula with medications alters nutrients other than the intended target(s). Future studies should be aimed at predicting the loss of these nutrients or identifying alternative methods for managing serum potassium and phosphorus levels in formula-fed infants. The safety of pretreating formula with SPS suspension should also be examined.

Trace elements in dialysis

In end-stage chronic kidney disease (CKD), pediatric nephrologists must consider the homeostasis of the multiple water-soluble ions that are influenced by renal replacement therapy (RRT). While certain ions such as potassium and calcium are closely monitored, little is known about the handling of trace elements in pediatric dialysis. RRT may lead to accumulation of toxic trace elements, either due to insufficient elimination or due to contamination, or to excessive removal of essential trace elements. However, trace elements are not routinely monitored in dialysis patients and no mechanism for these deficits or toxicities has been established. This review summarizes the handling of trace elements, with particular attention to pediatric data. The best data describe lead and indicate that there is a higher prevalence of elevated lead (Pb, atomic number 82) levels in children on RRT when compared to adults. Lead is particularly toxic in neurodevelopment and lead levels should therefore be monitored. Monitoring of zinc (Zn, atomic number 30) and selenium (Se, atomic number 34) may be indicated in the monitoring of all pediatric dialysis patients to reduce morbidity from deficiency. Prospective studies evaluating the impact of abnormal trace elements and the possible therapeutic value of intervention are required.