Demonstration of the effectiveness of zinc in diarrhoea of children living in Switzerland

Acute gastroenteritis-changes to the recommended original oral rehydrating salts: a review

The World Health Organization recommended a formulation of oral rehydration salts as the intervention of choice for the treatment of acute gastroenteritis. While of value for the replacement of fluids and electrolytes, the formulation does not reduce stool volume, frequency, or symptom duration. This may prevent wide acceptance. To increase tolerability, shorten the duration of diarrhea and improve parental quality of life, several modifications to the original formula have been proposed. These include; low osmolarity, rice-based, glucose polymers as an alternative to glucose, the addition of probiotics, prebiotics and/or zinc, and various other ingredients. Here we summarize evidence regarding such changes and additions.

Paracellular Filtration Secretion Driven by Mechanical Force Contributes to Small Intestinal Fluid Dynamics

Studies of fluid secretion by the small intestine are dominated by the coupling with ATP-dependent generation of ion gradients, whereas the contribution of filtration secretion has been overlooked, possibly by the lack of a known mechanistic basis. We measured apical fluid flow and generation of hydrostatic pressure gradients by epithelia of cultured mouse enterocytes, Caco-2 and T-84 cells, and fibroblasts exposed to mechanical force provided by vigorous aeration and in response to ion gradients, inhibitors of ion channels and transporters and in vitro using intact mouse and rat small intestine. We describe herein a paracellular pathway for unidirectional filtration secretion that is driven by mechanical force, requires tight junctions, is independent of ionic and osmotic gradients, generates persistent hydrostatic pressure gradients, and would contribute to the fluid shifts that occur during digestion and diarrhea. Zinc inhibits the flow of fluid and the paracellular marker fluorescein isothyocyanate conjugated dextran (MW = 4 kD) across epithelia of cultured enterocytes (>95%; p < 0.001) and intact small intestine (>40%; p = 0.03). We propose that mechanical force drives fluid secretion through the tight junction complex via a “one-way check valve” that can be regulated. This pathway of filtration secretion complements chloride-coupled fluid secretion during high-volume fluid flow. The role of filtration secretion in the genesis of diarrhea in intact animals needs further study. Our findings may explain a potential linkage between intestinal motility and intestinal fluid dynamics.

Effects of Lactose-Restricted Regimen in Breastfeeding Children with Acute Diarrhea

BACKGROUND

Acute diarrhea is a major cause of mortality in children. Few studies have addressed the administration of lactose-restricted diets in breastfed children with acute diarrhea. The present study was conducted to investigate the effects of a lactose-restricted regimen on breastfed children with acute diarrhea treated with zinc supplements.

METHODS

The present single-blind randomized clinical trial was conducted on children aged 6-24 months in Amirkola Children's Hospital (2015-2017). 90 children were randomly assigned to two groups. Group A was daily treated with 20 mg of zinc and a lactose-restricted diet and breast milk for two weeks. Group B received 20 mg of zinc and breast milk and an age-appropriate diet for two weeks. The data collected in all the subjects included the frequency of diarrhea and the mean duration of hospitalization and recovery from diarrhea.

RESULTS

The two groups were not significantly different in terms of mean age, weight and ratio of males to females. The mean duration of hospitalization was found to be 3.1 ± 0.8 days in group A and 3.2 ± 0.6 in group B (P = 0.3), the mean duration of recovery to be 2.9 ± 0.8 in group A and 2.6 ± 1.1 in group B (P = 0.2) and the mean frequency of diarrhea 2.9 ± 0.7 in group A and 2.8 ± 0.8 days in group B (P = 0.5), suggesting no significant differences between the two groups. No adverse effects associated with zinc therapy were reported.

CONCLUSIONS

A lactose-restricted regimen was found not to be beneficial for children with acute diarrhea under continuous breastfeeding and zinc therapy.

Acute Infectious Diarrhea and Gastroenteritis in Children

PURPOSE OF REVIEW

We aimed to summarize the most current evidence on the main aspects of the diarrheal diseases in children. The following key elements were addressed: definitions, etiology, pathogenesis, diagnosis, dietary management, pharmacological treatments, and prevention. We covered the following questions: What are the most important clinical and laboratory features of the disease? What are the best approaches for the dietary management? What is the best way to classify the hydration status, and to prevent and treat the dehydration? What are the most effective and safe interventions for reducing the diarrhea and vomiting?

RECENT FINDINGS

Diarrheal diseases are one of the most common diseases in childhood. The most common cause is rotavirus. A key element in the approach of a child with diarrhea is determining their hydration status, which determines the fluid management. Laboratory tests are nor routinely required, as most of the cases, they do not affect the management and it should be indicated only in selected cases. Several treatments have been studied to reduce the duration of the diarrhea. Only symbiotics and zinc have shown to be effective and safe with high certainty on the evidence. Rest of the interventions although seem to be effective have low to very low quality of the evidence. The only effective and safe antiemetic for controlling vomiting is ondansetron. A list of antimicrobials indications according to the identified microorganisms is provided. We summarized the most current evidence on diagnosis, management, and prevention of diarrhea in children. More research is needed in some areas such as dehydration scales, rehydration management, antidiarrheals, and antibiotic treatments.

Effect of dose reduction of supplemental zinc for childhood diarrhoea: study protocol for a double-masked, randomised controlled trial in India and Tanzania

BACKGROUND

Diarrhoea-associated mortality and morbidity are highest in infants and young children in low-income and middle-income countries (LMICs). Zinc supplementation during acute diarrhoea has been shown to reduce the duration of illness and the risk of persistent diarrhoea. However, vomiting with zinc supplementation is a common side effect that may interfere with compliance and programmatic scale-up, and may be related to the dose prescribed.

METHODS/DESIGN

The Zinc Therapeutic Dose Trial (ZTDT) is a two-centre (Tanzania and India), three-arm randomised, double-blind controlled non-inferiority trial. Children 6-59 months of age with acute diarrhoea are eligible to participate. Enrolled children (1500 per arm; 4500 total) will be randomly allocated to receive 5, 10 or 20 mg of zinc sulfate daily for 14 days and will be followed up for 60 days after enrolment. All children will receive WHO/Unicef Integrated Management of Childhood Illness standard of care (oral or intravenous rehydration and zinc as indicated and feeding advice). The primary efficacy outcomes of the trial are the percentage of subjects with diarrhoea duration >5 days, the mean total number of loose or watery stools after enrolment and the proportion of children vomiting within 30 min of zinc administration.

DISCUSSION

The ZTDT trial will determine the optimal dose of therapeutic zinc supplements for treatment of acute diarrhoea in children aged 6-59 months in two LMICs. The results of the trial are likely to be generalisable to childhood acute diarrhoea in similar resource-limited settings and may influence global policy about zinc supplementation dosage during acute diarrhoea.

TRIAL REGISTRATION NUMBER

NCT03078842.

TRIAL STATUS

Enrolment began in January 2017 and follow-up is estimated to be completed by April 2019. As of 1 February 2019, 742 children are still contributing data to the ZTDT study.

Effect of Zinc Supplementation on the Frequency and Consistency of Stool in Children with Acute Diarrhea

Introduction

Acute diarrhea in young children is a prevalent and distressing pediatric illness. The role of zinc therapy in the improvement of stool consistency and the shortening of the duration of diarrhea is still controversial. The aim of this study is to assess the effect of oral zinc supplementation in acute diarrhea.

Methods

Children of age 28 days till five years presenting in the outpatient department with acute diarrhea were included. Oral zinc supplementation was included in the anti-diarrheal regime of half of the children (n=50); the other half (n=50) were not given zinc. Mean body weight and the frequency and consistency of stool were noted for both groups on Days 1 and 3.

Results

The zinc group showed a significantly reduced frequency of diarrheal episodes on the third day of intervention (p<.00001). More children in the zinc group had soft to firm stool consistency than in the non-zinc group (p=.01).

Conclusion

Oral zinc supplementation has a promising role in reducing the duration of diarrhea and improving stool consistency in children with acute diarrhea. Oral zinc supplementation should be made a mandatory part of the anti-diarrheal regime for Pakistani children.

Drug-development concepts as guides for optimizing clinical trials of supplemental zinc for populations at risk of deficiency or diarrhea

Studies on the efficacy of zinc supplementation for treatment or prevention of diarrhea have shown an inconsistent effect in populations at risk for zinc deficiency. Unlike drugs, which have no preexisting presence in the body, endogenous zinc must be assessed pharmacokinetically by isotope tracer studies. Although such methods have produced much data, very few studies have estimated the dose and the timing of dosing of zinc supplementation. This review examines drug kinetics used to establish the best dose, the timing of such doses, and the mechanism of action through pharmacodynamic markers and applies them, where possible, to zinc supplements. The findings reveal that little is known, especially in children at highest risk of zinc deficiency. Key data missing to inform proper dosing, whether for treatment of disease or for preventive nutrient supplementation, are noted. Addressing these uncertainties could improve study design, leading to future studies of zinc supplements that might be of greater benefit.

The Zn2+-sensing receptor, ZnR/GPR39, upregulates colonocytic Cl- absorption, via basolateral KCC1, and reduces fluid loss

Administration of zinc, as a complement to oral rehydration solutions, effectively diminishes duration and severity of diarrhea, but it is not known whether it merely fulfills a nutritional deficiency, or if zinc has a direct role of regulating solute absorption. We show that Zn2+ acts via a specific receptor, ZnR/GPR39, to reduce fluid loss. Intestinal fluid secretion triggered by cholera toxin (CTx) was lower in WT mice compared to ZnR/GPR39 KO. In the absence of dietary Zn2+ we observed similar fluid accumulation in WT and ZnR/GPR39 KO mice, indicating that Zn2+ and ZnR/GPR39 are both required for a beneficial effect of Zn2+ in diarrhea. In primary colonocytes and in Caco-2 colonocytic cells, activation of ZnR/GPR39 enhanced Cl- transport, a critical factor in diarrhea, by upregulating K+/Cl- cotransporter (KCC1) activity. Importantly, we show basolateral expression of KCC1 in mouse and human colonocytes, thus identifying a novel Cl- absorption pathway. Finally, inhibition of KCC-dependent Cl- transport enhanced CTx-induced fluid loss. Altogether, our data indicate that Zn2+ acting via ZnR/GPR39 has a direct role in controlling Cl- absorption via upregulation of basolateral KCC1 in the colon. Moreover, colonocytic ZnR/GPR39 and KCC1 reduce water loss during diarrhea and may therefore serve as effective drug targets.

Oral zinc for treating diarrhoea in children

BACKGROUND

In developing countries, diarrhoea causes around 500,000 child deaths annually. Zinc supplementation during acute diarrhoea is currently recommended by the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF).

OBJECTIVES

To evaluate oral zinc supplementation for treating children with acute or persistent diarrhoea.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (the Cochrane Library 2016, Issue 5), MEDLINE, Embase, LILACS, CINAHL, mRCT, and reference lists up to 30 September 2016. We also contacted researchers.

SELECTION CRITERIA

Randomized controlled trials (RCTs) that compared oral zinc supplementation with placebo in children aged one month to five years with acute or persistent diarrhoea, including dysentery.

DATA COLLECTION AND ANALYSIS

Both review authors assessed trial eligibility and risk of bias, extracted and analysed data, and drafted the review. The primary outcomes were diarrhoea duration and severity. We summarized dichotomous outcomes using risk ratios (RR) and continuous outcomes using mean differences (MD) with 95% confidence intervals (CI). Where appropriate, we combined data in meta-analyses (using either a fixed-effect or random-effects model) and assessed heterogeneity.We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

Thirty-three trials that included 10,841 children met our inclusion criteria. Most included trials were conducted in Asian countries that were at high risk of zinc deficiency. Acute diarrhoeaThere is currently not enough evidence from well-conducted RCTs to be able to say whether zinc supplementation during acute diarrhoea reduces death or number of children hospitalized (very low certainty evidence).In children older than six months of age, zinc supplementation may shorten the average duration of diarrhoea by around half a day (MD -11.46 hours, 95% CI -19.72 to -3.19; 2581 children, 9 trials, low certainty evidence), and probably reduces the number of children whose diarrhoea persists until day seven (RR 0.73, 95% CI 0.61 to 0.88; 3865 children, 6 trials, moderate certainty evidence). In children with signs of malnutrition the effect appears greater, reducing the duration of diarrhoea by around a day (MD -26.39 hours, 95% CI -36.54 to -16.23; 419 children, 5 trials, high certainty evidence).Conversely, in children younger than six months of age, the available evidence suggests zinc supplementation may have no effect on the mean duration of diarrhoea (MD 5.23 hours, 95% CI -4.00 to 14.45; 1334 children, 2 trials, moderate certainty evidence), or the number of children who still have diarrhoea on day seven (RR 1.24, 95% CI 0.99 to 1.54; 1074 children, 1 trial, moderate certainty evidence).None of the included trials reported serious adverse events. However, zinc supplementation increased the risk of vomiting in both age groups (children greater than six months of age: RR 1.57, 95% CI 1.32 to 1.86; 2605 children, 6 trials, moderate certainty evidence; children less than six months of age: RR 1.54, 95% CI 1.05 to 2.24; 1334 children, 2 trials, moderate certainty evidence). Persistent diarrhoeaIn children with persistent diarrhoea, zinc supplementation probably shortens the average duration of diarrhoea by around 16 hours (MD -15.84 hours, 95% CI -25.43 to -6.24; 529 children, 5 trials, moderate certainty evidence).

AUTHORS' CONCLUSIONS

In areas where the prevalence of zinc deficiency or the prevalence of malnutrition is high, zinc may be of benefit in children aged six months or more. The current evidence does not support the use of zinc supplementation in children less six months of age, in well-nourished children, and in settings where children are at low risk of zinc deficiency.

Adherence to zinc supplementation guidelines for the treatment of diarrhea among children under-five in Uttar Pradesh, India

BACKGROUND

There is limited evidence on adherence to the recommended dose and duration of zinc supplementation for diarrheal episodes in children under five years of age. In selected districts of Uttar Pradesh, India, we sought to assess adherence to the nationally advised zinc treatment regimen (ie, 10 mg/day for ages 2-6 months and 20 mg/day for ages 7-59 months for 14 days) among caregivers of zinc-prescribed children.

METHODS

We identified and conducted follow-up visits to children advised zinc for the treatment of diarrhea. At the initial visit, we collected data on the treatment instructions received from providers. Caregivers were asked to record treatments administered on a pictorial tracking form and were asked to retain all packaging for collection at follow-up. We quantified the average dose and duration of zinc therapy and built logistic regression models to assess the factors associated with caregiver adherence to national guidelines.

RESULTS

Caregivers administered zinc for an average of 10.7 days (standard deviation (SD) = 3.9 days; median = 13 days), and 47.8% continued treatment for the complete 14 days. Among children receiving zinc syrups and tablets respectively, the age appropriate dose was received by 30.8% and 67.3%. Adherence to age appropriate dose and continuation of zinc for 14 days were highly associated with having received appropriate provider instructions.

CONCLUSIONS

Our results indicate moderate-to-good adherence to national zinc treatment guidelines for diarrhea among caregivers in rural India. Our findings also highlight the importance of provider guidance in ensuring adherence to zinc dose and duration. Programs aiming to scale-up zinc treatment for childhood diarrhea should train providers to successfully communicate dosing instructions to caregivers, while also addressing the tendency of caregivers to terminate treatment once a child appears to have recovered from an acute diarrheal episode.

Biomarkers of Nutrition for Development (BOND)-Zinc Review

Zinc is required for multiple metabolic processes as a structural, regulatory, or catalytic ion. Cellular, tissue, and whole-body zinc homeostasis is tightly controlled to sustain metabolic functions over a wide range of zinc intakes, making it difficult to assess zinc insufficiency or excess. The BOND (Biomarkers of Nutrition for Development) Zinc Expert Panel recommends 3 measurements for estimating zinc status: dietary zinc intake, plasma zinc concentration (PZC), and height-for-age of growing infants and children. The amount of dietary zinc potentially available for absorption, which requires an estimate of dietary zinc and phytate, can be used to identify individuals and populations at risk of zinc deficiency. PZCs respond to severe dietary zinc restriction and to zinc supplementation; they also change with shifts in whole-body zinc balance and clinical signs of zinc deficiency. PZC cutoffs are available to identify individuals and populations at risk of zinc deficiency. However, there are limitations in using the PZC to assess zinc status. PZCs respond less to additional zinc provided in food than to a supplement administered between meals, there is considerable interindividual variability in PZCs with changes in dietary zinc, and PZCs are influenced by recent meal consumption, the time of day, inflammation, and certain drugs and hormones. Insufficient data are available on hair, urinary, nail, and blood cell zinc responses to changes in dietary zinc to recommend these biomarkers for assessing zinc status. Of the potential functional indicators of zinc, growth is the only one that is recommended. Because pharmacologic zinc doses are unlikely to enhance growth, a growth response to supplemental zinc is interpreted as indicating pre-existing zinc deficiency. Other functional indicators reviewed but not recommended for assessing zinc nutrition in clinical or field settings because of insufficient information are the activity or amounts of zinc-dependent enzymes and proteins and biomarkers of oxidative stress, inflammation, or DNA damage.