Plasma zinc as a predictor of diarrheal and respiratory morbidity in children in an urban slum setting

Vitamin D3 supplementation as an adjunct in the management of childhood infectious diarrhea: a systematic review

BACKGROUND

Some studies have reported the possible role of vitamin D₃ in ameliorating disease outcomes in childhood infectious diarrhea. However, findings about its effectiveness and the association of serum vitamin D levels with diarrhea risk appear inconsistent. We aimed to determine the efficacy of oral vitamin D₃ as an adjunct in managing childhood infectious diarrhea and the relationship between vitamin D status and the disease.

METHODS

We searched the PubMed and Google Scholar electronic databases for relevant articles without limiting their year of publication. We selected primary studies that met the review's inclusion criteria, screened their titles and abstracts, and removed duplicates. We extracted data items from selected studies using a structured data-extraction form. We conducted a quality assessment of randomized controlled trials (RCTs) and non-randomized studies with the Cochrane collaboration tool and the Newcastle Ottawa Scale, respectively. We assessed the strength of the relationship between serum vitamin D levels and diarrhea using the correlation model. We estimated the I² and tau² values to assess between-study heterogeneity.

RESULTS

Nine full-text articles were selected, consisting of one RCT, three cross-sectional studies, two cohort studies, two longitudinal/prospective studies, and one case-control study. A total of 5,545 participants were evaluated in the nine studies. Six non-randomized studies provided weak evidence of the relationship between vitamin D levels and diarrhea risk as there was no correlation between the two variables. The only RCT failed to demonstrate any beneficial role of vitamin D₃ in reducing the risk of recurrent diarrhea. The calculated I² and tau² values of 86.5% and 0.03, respectively suggested a high between-study heterogeneity which precluded a meta-analysis of study results.

CONCLUSION

Oral vitamin D₃ may not be an effective adjunct in managing childhood infectious diarrhea. Additionally, the relationship between vitamin D status and infectious diarrhea appears weak. We recommend more adequately-powered RCTs to determine the effectiveness of vitamin D₃ as an adjunct therapy in infectious diarrhea.

Determination of the optimal dietary zinc content for pigs between 10 and 30 kg body weight

The Zn requirement of pigs immediately after weaning is more investigated compared to the Zn requirement in the growth period between 10 and 30 kg. Unabsorbed and excessive dietary Zn is excreted mainly through feces, and spreading pig slurry to fields can cause environmental issues because high levels of Zn can impair plant growth and contribute to the development of antimicrobial resistance genes in microorganisms. Therefore, more precise knowledge of Zn requirements and dietary Zn recommendations is important. The present study investigated the optimal dietary Zn content for 10- to 30-kg pigs. The study used 150 pigs weaned at 28 d of age (day 0) and supplied with 1,474 mg dietary Zn/kg the first 2 wk post-weaning. After 2 wk, pigs were randomly distributed according to body weight (BW; 10.1 ± 0.3 kg) and sex, to individually housing, and fed a diet supplemented with either 0, 30, 60, 120, or 240 mg Zn/kg (from ZnO), resulting in total dietary Zn contents of 80, 92, 117, 189, and 318 mg/kg until week 6 post-weaning. BW, feed intake, and fecal scores were recorded, and samples of blood (weeks 2, 3, 5, and 6) and tissues (week 6) were collected. The feed intake, growth, feed efficiency, relative weight of the pancreas and liver, Zn concentration in the liver, and pancreatic digestive enzyme activity were unaffected by dietary Zn content (P > 0.12). The serum Zn level decreased (P < 0.01) by up to 24% from weeks 2 to 3. The serum Zn concentrations in weeks 5 and 6 were similar to in week 2 when 117, 189, and 318 mg Zn/kg were provided, while with 80 and 92 mg Zn/kg the serum Zn concentration was lower (P < 0.01) than in week 2. The serum Zn concentration reached a plateau in weeks 5 and 6, and breakpoints were calculated at 126 ± 17 and 102 ± 6 mg Zn/kg, respectively. Bone Zn status was greater (P < 0.01) with 189 than 80 mg Zn/kg and a breakpoint was calculated at 137 ± 19 mg Zn/kg. According to performance, the Zn requirement for 10- to 30-kg pigs can be fulfilled with 80 mg total Zn/kg, but based on serum and bone Zn status, the optimal total dietary Zn content is 102 to 137 mg/kg. The latter corresponds to a daily Zn intake (requirement) of 103 to 138 mg when calculated from the average feed intake during weeks 3 to 6 (1,005 g/d). Importantly, the presented results are obtained in pigs supplied with 1,474 mg Zn/kg from ZnO the first 2 wk post-weaning and a high level of phytase (1,000 phytase units) in the diet throughout the experiment.

Determination of the Optimal Level of Dietary Zinc for Newly Weaned Pigs: A Dose-Response Study

Simple Summary

Piglets have a very low feed intake immediately after weaning. We hypothesise that the EU-legislated maximum dietary zinc concentration (150 mg zinc/kg diet) will increase the risk of zinc deficiency after weaning. Zinc deficiency includes symptoms such as impaired growth and increased risk of diarrhoea. However, a high dietary zinc concentration has an antimicrobial effect on the bacteria and increases the risk of antimicrobial resistance. The findings of this study show that the dietary zinc level had a quadratic effect on growth, with a turning point at an approximately 1400 mg zinc per kg diet. The risk of diarrhoea increased up to 60% for pigs that had a blood zinc concentration which decreased after weaning. Maintaining the blood zinc concentration seven days after weaning required up to 1121 mg zinc per kg diet. There was no evidence for an antimicrobial effect when feeding pigs a diet with up to 1601 mg zinc per kg.

Abstract

One hundred and eighty individually housed piglets with an initial body weight of 7.63 ± 0.98 kg (at 28 days of age) were fed a diet containing either 153, 493, 1022, 1601, 2052 or 2407 mg zinc/kg (added Zn as zinc oxide; ZnO) from day 0–21 post weaning to determine the optimal level of Zn for weaned piglets. Body weight, feed intake and faecal scores were recorded, and blood and faecal samples were collected. Dietary Zn content quadratically affected both feed intake and gain in the first two weeks, with an approximately 1400 mg Zn/kg diet and a Zn intake of 400 mg/day as the optimal levels. The relative risk of diarrhoea increased up to 60% at day 7 and 14 if serum Zn status dropped below the weaning level (767 µg/L), and maintain the weaning serum Zn status required approximately 1100 mg Zn/kg (166 mg Zn/day) during week 1. Blood markers of intestinal integrity (D-lactate and diamine oxidase) were unaffected by dietary Zn, and dietary Zn levels of 1022 and 1601 mg/kg did not affect the faecal numbers of total bacteria, Lactobacilli and E. Coli bacteria compared to 153 mg Zn/kg. These results indicate that the requirement for Zn in newly weaned piglets may be substantially higher than currently assumed.

Control and prevention of infectious diseases from a One Health perspective

The ongoing COVID-19 pandemic has caught the attention of the global community and rekindled the debate about our ability to prevent and manage outbreaks, epidemics, and pandemics. Many alternatives are suggested to address these urgent issues. Some of them are quite interesting, but with little practical application in the short or medium term. To realistically control infectious diseases, human, animal, and environmental factors need to be considered together, based on the One Health perspective. In this article, we highlight the most effective initiatives for the control and prevention of infectious diseases: vaccination; environmental sanitation; vector control; social programs that encourage a reduction in the population growth; control of urbanization; safe sex stimulation; testing; treatment of sexually and vertically transmitted infections; promotion of personal hygiene practices; food safety and proper nutrition; reduction of the human contact with wildlife and livestock; reduction of social inequalities; infectious disease surveillance; and biodiversity preservation. Subsequently, this article highlights the impacts of human genetics on susceptibility to infections and disease progression, using the SARS-CoV-2 infection as a study model. Finally, actions focused on mitigation of outbreaks and epidemics and the importance of conservation of ecosystems and translational ecology as public health strategies are also discussed.

A comparative study of the prevalence of zinc deficiency among children with acute diarrhoea in SouthWestern Nigeria

Background

Zinc deficiency has been associated with increased incidence, severity and duration of childhood diarrhoea.

Objective

The objective of the study was to determine the prevalence of zinc deficiency among under-five children with acute diarrhoea.

Methods

The study was a comparative cross-sectional study in which serum zinc levels were determined using atomic absorption spectrometry in under-five children with acute diarrhoea and in apparently healthy contols. Two hundred and fifty children with acute diarrhoea and 250 controls were studied at the Wesley Guild Hospital, Ilesa, Nigeria.

Results

The diarrhoea patients had a mean ± SD serum zinc level of 78.8 ± 35.6 µg/dl, while the controls had a mean of 107.3 ± 46.8 µg/dl. The mean serum zinc level was significantly lower in the patients than the controls (t = -7.66; p < 0.001). Furthermore, the prevalence of zinc deficiency was significantly higher among the patients (30.4% versus 12.4% in the controls; OR = 3.09; 95% CI = 1.94 – 4.90; χ2 = 24.08; p < 0.001). Low social class was associated with a significantly higher prevalence of zinc deficiency among the patients (p = 0.013).

Conclusion

Zinc deficiency is significantly associated with diarrhoea among under-five children in the study community. Hence, routine zinc supplementation should be encouraged for the treatment of diarrhoea, and availability should be ensured.

Zinc Deficiency and the Recurrence of Clostridium difficile Infection after Fecal Microbiota Transplant: A Retrospective Cohort Study

Background

Fecal microbiota transplant (FMT) is an effective therapy for recurrent Clostridium difficile infection (CDI). However, in 12% of patients treated with FMT, CDI recurs within one month. Zinc deficiency predicts increased diarrheal frequency in malnourished children, but little is known about its association with FMT outcome. We hypothesized that zinc levels were an independent predictor of CDI recurrence after FMT.

Methods

We performed a retrospective cohort study of 80 patients (mean age, 66; 59 women) receiving FMT for CDI from 9/2013–9/2016 at a tertiary care center. Zinc levels were measured within 90 days before FMT. The primary outcome was CDI recurrence within 90 days after FMT. We controlled for risk factors for FMT failure using Cox regression. We also analyzed the effect of zinc supplementation in individuals with deficiency.

Results

Forty-nine subjects had a normal zinc level, and 31 had a low level (<0.66 µg/mL). CDI recurred in 3/49 (6%) patients with normal zinc and 5/31 (16%) patients with low zinc (HR = 11.327, 95% CI = 2.162–59.336, p=0.004). Among low zinc subjects, 2 of 25 (8%) that received zinc supplements and 3 of 6 (50%) that did not receive zinc supplements had recurrence of CDI (HR = 0.102, 95% CI = 0.015–0.704, p=0.021).

Conclusion

Zinc deficiency was associated with increased CDI recurrence after FMT. Among zinc-deficient patients, supplementation was associated with reduced recurrence. Further study is needed to determine whether zinc deficiency represents a pathophysiologic mechanism and target for therapy.

Low serum zinc level: The relationship with severe pneumonia and survival in critically ill children

BACKGROUND

Zinc deficiency is common among children in developing countries; but, there is still conflicting evidence on whether the alteration in zinc metabolism is the predictive of disease severity in the setting of critical illness.

OBJECTIVES

To assess serum zinc levels in children admitted with pneumonia, and also to study the relationship between zinc levels and severity and mortality from pneumonia.

METHODS

In a prospective cohort study, we enrolled 320 critically ill children admitted to the paediatric intensive care unit (PICU) with severe pneumonia (group 1) in addition to 160 children admitted into wards with pneumonia (group 2). Serum zinc measured in all patients on admission.

RESULTS

Serum zinc level was significantly lower among patients admitted to PICU (group 1) compared with patients admitted to wards (group 2) (P < .001). There was a highly statistically significant decrease in zinc level in critically ill children complicated by sepsis, mechanically ventilated cases and those who died. Regarding the diagnosis of sepsis, zinc had an area under the curve (AUC) of 0.81 while C-reactive protein (CRP) had an AUC of 0.83. Regarding the prognosis, zinc had an AUC of 0.649 for prediction of mortality, whereas the AUC for Pediatric risk of mortality (PRISM), Pediatric index of mortality2 (PIM2) and CRP were 0.83, 0.82 and 0.78, respectively. The combined zinc with PRISM and PIM2 has increased the sensitivity of zinc for mortality from 86.5% to 94.9%.

CONCLUSION

Zinc has both a diagnostic and a prognostic value for children with pneumonia.

Neurotoxicants, Micronutrients, and Social Environments

SUMMARY—Systematic research evaluating the separate and interacting impacts of neurotoxicants, micronutrients, and social environments on children's cognition and behavior has only recently been initiated. Years of extensive human epidemiologic and animal experimental research document the deleterious impact of lead and other metals on the nervous system. However, discrepancies among human studies and between animal and human studies underscore the importance of variations in child nutrition as well as social and behavioral aspects of children's environments that mitigate or exacerbate the effects of neurotoxicants.

In this monograph, we review existing research on the impact of neurotoxic metals, nutrients, and social environments and interactions across the three domains. We examine the literature on lead, mercury, manganese, and cadmium in terms of dispersal, epidemiology, experimental animal studies, effects of social environments, and effects of nutrition.

Research documenting the negative impact of lead on cognition and behavior influenced reductions by the Center for Disease Control in child lead-screening guidelines from 30 micrograms per deciliter (μg/dL) in 1975 to 25 μg/dL in 1985 and to 10 μg/dL in 1991. A further reduction is currently being considered. Experimental animal research documents lead's alteration of glutamate-neurotransmitter (particularly N-methyl-D-aspartate) activity vital to learning and memory. In addition, lead induces changes in cholinergic and dopaminergic activity. Elevated lead concentrations in the blood are more common among children living in poverty and there is some evidence that socioeconomic status influences associations between lead and child outcomes. Micronutrients that influence the effects of lead include iron and zinc.

Research documenting the negative impact of mercury on children (as well as adults) has resulted in a reference dose (RfD) of 0.1 microgram per kilogram of body weight per day (μg/kg/day). In animal studies, mercury interferes with glutamatergic, cholinergic, and dopaminergic activity. Although evidence for interactions of mercury with children's social contexts is minimal, researchers are examining interactions of mercury with several nutrients.

Research on the effects of cadmium and manganese on child cognition and behavior is just beginning. Experimental animal research links cadmium to learning deficits, manganese to behaviors characteristic of Parkinson's disease, and both to altered dopaminergic functioning.

We close our review with a discussion of policy implications, and we recommend interdisciplinary research that will enable us to bridge gaps within and across domains.

Efficacy of highly bioavailable zinc from fortified water: a randomized controlled trial in rural Beninese children

BACKGROUND

Zinc deficiency and contaminated water are major contributors to diarrhea in developing countries. Food fortification with zinc has not shown clear benefits, possibly because of low zinc absorption from inhibitory food matrices. We used a novel point-of-use water ultrafiltration device configured with glass zinc plates to produce zinc-fortified, potable water.

OBJECTIVE

The objective was to determine zinc bioavailability from filtered water and the efficacy of zinc-fortified water in improving zinc status.

DESIGN

In a crossover balanced study, we measured fractional zinc absorption (FAZ) from the zinc-fortified water in 18 healthy Swiss adults using zinc stable isotopes and compared it with zinc-fortified maize porridge. We conducted a 20-wk double-blind randomized controlled trial (RCT) in 277 Beninese school children from rural settings who were randomly assigned to receive a daily portion of zinc-fortified filtered water delivering 2.8 mg Zn (Zn+filter), nonfortified filtered water (Filter), or nonfortified nonfiltered water (Pump) from the local improved supply, acting as the control group. The main outcome was plasma zinc concentration (PZn), and the 3 groups were compared by using mixed-effects models. Secondary outcomes were prevalence of zinc deficiency, diarrhea prevalence, and growth.

RESULTS

Geometric mean (-SD, +SD) FAZ was 7-fold higher from fortified water (65.9%; 42.2, 102.4) than from fortified maize (9.1%; 6.0, 13.7; P < 0.001). In the RCT, a significant time-by-treatment effect on PZn (P = 0.026) and on zinc deficiency (P = 0.032) was found; PZn in the Zn+filter group was significantly higher than in the Filter (P = 0.006) and Pump (P = 0.025) groups. We detected no effect on diarrhea or growth, but our study did not have the duration and power to detect such effects.

CONCLUSIONS

Consumption of filtered water fortified with a low dose of highly bioavailable zinc is an effective intervention in children from rural African settings. Large community-based trials are needed to assess the effectiveness of zinc-fortified filtered water on diarrhea and growth. These trials were registered at clinicaltrials.gov as NCT01636583 and NCT01790321.

Zinc supplementation fails to increase the immunogenicity of oral poliovirus vaccine: a randomized controlled trial

BACKGROUND

Polio eradication remains a challenge in Pakistan and the causes for the failure to eradicate poliomyelitis are complex. Undernutrition and micronutrient deficiencies, especially zinc deficiency, are major public health problems in Pakistan and could potentially affect the response to enteric vaccines, including oral poliovirus vaccine (OPV).

OBJECTIVE

To assess the impact of zinc supplementation among infants on immune response to oral poliovirus vaccine (OPV).

METHODS

A double-blind, randomized placebo-controlled trial was conducted in newborns (aged 0-14 days). Subjects were assigned to either receive 10mg of zinc or placebo supplementation daily for 18 weeks. Both groups received OPV doses at birth, at 6 weeks, 10 weeks and 14 weeks. Data was collected on prior immunization status, diarrheal episodes, breastfeeding practices and anthropometric measurements at recruitment and at 6 and 18 weeks. Blood samples were similarly collected to determine the antibody response to OPV and for micronutrient analysis. Logistic regression was used to determine the relationship between seroconversion and zinc status.

RESULTS

Overall, 404 subjects were recruited. At recruitment, seropositivity was already high for poliovirus (PV) serotype 1 (zinc: 91.1%; control: 90.5%) and PV2 (90.0%; 92.7%), with lower estimates for PV3 (70.0%; 64.8%). By week 18, the proportion of subjects with measured zinc levels in the normal range (i.e. ≥60 μg/dL) was significantly greater in the intervention group compared to the control group (71.9%; 27.4%; p<0.001). No significant difference in seroconversion was demonstrated between the groups for PV1, PV2, or PV3.

CONCLUSIONS

There was no effect of zinc supplementation on OPV immunogenicity. These conclusions were confirmed when restricting the analysis to those with measured higher zinc levels.

Early childhood diarrhoeal diseases and cognition: are we missing the rest of the iceberg?

Risk factors which interfere with cognitive function are especially important during the first 2 years of life - a period referred to as early child development and a time during which rapid growth and essential development occur. Malnutrition, a condition whose effect on cognitive function is well known, has been shown to be part of a vicious cycle with diarrhoeal diseases, and the two pathologies together continue to be the leading cause of illness and death in young children in developing countries. This paper reviews the burden of early childhood diarrhoeal diseases globally and the emerging evidence of their relationship with global disparities in neurocognitive development. The strength of evidence which indicates that the severe childhood diarrhoeal burden may be implicated in cognitive impairment of children from low- and middle-income counties is discussed. Findings suggest that greater investment in multi-site, longitudinal enteric infection studies that assess long-term repercussions are warranted. Furthermore, economic analyses using the concept of human capital should play a key role in advancing our understanding of the breadth and complexities of the health, social and economic ramifications of early childhood diarrhoeal diseases and enteric infections. This broadened awareness can serve to help advocate for more effective interventions, particularly in developing economies.

Serum zinc levels in hospitalized children with acute lower respiratory infections in the north-central region of Nigeria

BACKGROUND

Macronutrient deficiency has continued to attract significant research interest, where as the import of micronutrients like zinc has only recently become the focus of interest. Thus against the background of a dearth of data on zinc levels in Nigerian children with Acute Lower Respiratory Infection (ALRI), this study was carried out in Ilorin, Nigeria to determine the serum zinc levels in hospitalized children with ALRI.

METHODOLOGY

A comparative cross-sectional hospital based study involving 120 children aged two months to five years with ALRI recruited as subjects, and 120 age-appropriate controls without ALRI was carried out. Socio-demographic, clinical and laboratory data were obtained. The serum zinc was analyzed with a Jenway™ spectrophotometer after an initial preparation with the QuantiChrom™ zinc assay kit.

RESULTS

The male/ female ratio was 1.6:1. The mean (SD) serum zinc level in subjects with ALRI of 18.7(11.8)µg/dl was significantly lower than the corresponding value of 53.1(18.5)µg/dl recorded in the controls, p=0.001. The prevalence of 98.3% for low serum zinc levels recorded in children with ALRI was significantly higher than that recorded in controls of 64.2%, p=0.001.

CONCLUSION

Low serum zinc levels are significantly associated with ALRI. There is a need to determine whether hospitalized children managed for ALRI might benefit from post discharge zinc supplementation.

Comparison of the serum concentration of zinc in patients with bronchiectasis and control group

BACKGROUND

Bronchiectasis is an abnormal and permanent dilatation of bronchi. Infection plays a major role in causing and perpetuating bronchiectasis, as reducing the microbial load and attendant mediators are cornerstone of therapy. Zinc, as an integral micronutrient is involved in the immune reactions including response to infection. In several previous studies, mild zinc deficiency has been described in many infectious diseases such as abscess, cellulitis, chronic diarrhea, pneumonia, tuberculosis (TB), etc.

OBJECTIVES

The purpose of this study was to determine serum zinc level in a series of patients suffering from bronchiectasis and to compare it with healthy control group.

PATIENTS AND MATERIALS

This analytical cross-sectional study was performed on thirty four patients with proven bronchiectasis and twenty nine healthy control subjects referred to Rasoul-e-Akram Hospital, Tehran, Iran, between March 2005 and March 2007. Serum concentration of the zinc was measured for all of the subjects and other information was completed according to their medical records. Both groups (case and control) were frequently matched regarding their age groups.

RESULTS

Patients included 11 (32.4%) males and 23 (67.6%) females with the average age of 55.03 (SD = 17.06) yr. The mean level of serum zinc in the case and control groups were 94.06 (SD = 20/96) mcg/dl and 103.7 (SD = 11.96) mcg/dl, respectively. Independent T-test analysis showed that serum zinc concentration in the case group of bronchiectasis patients was significantly lower than control group (P = 0.02).

CONCLUSIONS

The results of our study show that serum zinc level in bronchiectasis patients was lower than the control group and the difference was statistically significant. It seems that the use of zinc supplement can reduce progression of the infectious disease regarding its role in improving the immune system reactions and some unknown mechanisms. Therefore, prophylactic and therapeutic use of zinc must be evaluated in further trials.

A Comparative Study of Selected Trace Element Content in Malay and Chinese Traditional Herbal Medicine (THM) Using an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS)

A total of 60 products of traditional herbal medicine (THM) in various dosage forms of herbal preparation were analyzed to determine selected trace elements (i.e., Zn, Mn, Cu, Cd, and Se) using ICP-MS. Thirty types of both Chinese and Malay THMs were chosen to represent each population. The closed vessel acid microwave digestion method, using CEM MARS 5, was employed for the extraction of the selected trace elements. The digestion method applied was validated by using certified reference material from the Trace Element in Spinach Leaves (SRM1570a). The recoveries of all elements were found to be in the range of 85.3%-98.9%. The results indicated that Zn, Mn, Cu, Cd and Se have their own trends of concentrations in all samples studied. The daily intake concentrations of the elements were in the following order: Mn > Zn > Cu > Se > Cd. Concentrations of all five elements were found to be dominant in Chinese THMs. The essentiality of the selected trace elements was also assessed, based on the recommended daily allowance (RDA), adequate intake (AI) and the United States Pharmacopeia (USP) for trace elements as reference. The concentrations of all elements studied were below the RDA, AI and USP values, which fall within the essential concentration range, except for cadmium.

Risk factors for extended duration of acute diarrhea in young children

OBJECTIVE AND BACKGROUND

We sought to identify predictors of extended duration of diarrhea in young children, which contributes substantially to the nearly 1 1/2 million annual diarrheal deaths globally.

METHODS

We followed 6-35 month old Nepalese children enrolled in the placebo-arm of a randomized controlled trial with 391 episodes of acute diarrhea from the day they were diagnosed until cessation of the episode. Using multiple logistic regression analysis, we identified independent risk factors for having diarrhea for more than 7 days after diagnosis.

RESULTS

Infants had a 17 (95% CI 3.5, 83)-fold and toddlers (12 to 23 month olds) a 9.9 (95% CI 2.1, 47)-fold higher odds of having such illness duration compared to the older children. Not being breastfed was associated with a 9.3 (95% CI 2.4, 35.7)-fold increase in the odds for this outcome. The odds also increased with increasing stool frequency. Furthermore, having diarrhea in the monsoon season also increased the risk of prolonged illness.

CONCLUSION

We found that high stool frequency, not being breastfed, young age and acquiring diarrhea in the rainy season were risk factors for prolonged diarrhea. In populations such as ours, breastfeeding may be the most important modifiable risk factor for extended duration of diarrhea.

Enteropathies in the developing world: neglected effects on global health

A spectrum of enteropathies, characterized by small intestinal inflammation, reduced absorptive capacity, and increased intestinal permeability, commonly affect people in developing countries. This subclinical intestinal pathology facilitates microbial translocation across the compromised intestinal barrier, leading to chronic systemic inflammation that may adversely impact health. Environmental enteropathy (EE), ubiquitous among people living in unhygienic conditions, likely mediates two interlinked public health problems of childhood, stunting and anemia, and underlies poor oral vaccine efficacy in developing countries. Human immunodeficiency virus (HIV) enteropathy, which frequently overlaps with EE, may contribute to immune activation and modulate HIV disease progression. The interacting effects of infection and enteropathy drive a vicious cycle that can propagate severe acute malnutrition, which underlies almost half of under-5-y deaths. Enteropathies are therefore highly prevalent, interacting causes of morbidity and mortality in developing countries. Interventions to prevent or ameliorate enteropathies have potential to improve the health of millions of people in developing countries.

Systematic review of diarrhea duration and severity in children and adults in low- and middle-income countries

Background

Diarrhea is a leading cause of morbidity and mortality globally; yet the overall burden of diarrhea in terms of duration and severity has not been quantified. As improvements in treatment lead to decreases in diarrhea mortality, it is important to understand the substantial impact of diarrhea morbidity on disability among children and adults worldwide.

Methods

We conducted a systematic review to generate estimates of duration and severity outcomes for individuals 0-59 mos, 5-15 yrs, and ≥ 16 yrs, and for 3 severity indexes: mild, moderate, and severe.

Results

We estimate that among children under-five, 64.8% of diarrheal episodes are mild, 34.7% are moderate, and 0.5% are severe. On average, mild episodes last 4.3 days, and severe episodes last 8.4 days and cause dehydration in 84.6% of cases. We estimate that among older children and adults, 95% of episodes are mild; 4.95% are moderate; and 0.05% are severe. Among individuals ≥ 16 yrs, severe episodes typically last 2.6 days and cause dehydration in 92.8% of cases.

Conclusions

Moderate and severe episodes constitute a substantial portion of the total envelope of diarrhea among children under-five (35.2%; about 588 million episodes). Among older children and adults, moderate and severe episodes account for a much smaller proportion of the total envelope of diarrhea (5%), but the absolute number of such episodes is noteworthy (about 21.5 million episodes among individuals ≥ 16 yrs). Hence, the global burden of diarrhea consists of significant morbidity, extending beyond episodes progressing to death.

Zinc and its role in age-related inflammation and immune dysfunction

Zinc is an essential micronutrient required for many cellular processes, especially for the normal development and function of the immune system. Zinc homeostasis and signaling are critical in immune activation, and an imbalance in zinc homeostasis is associated with the development of chronic diseases. Zinc deficiency causes significant impairment in both adaptive and innate immune responses, and promotes systemic inflammation. The elderly are a population particularly susceptible to zinc deficiency. National surveys indicate that a significant portion of the aged population has inadequate zinc intake, and a decline in zinc status is observed with age. There are remarkable similarities between the hallmarks of zinc deficiency and immunological dysfunction in aged individuals. Both zinc deficiency and the aging process are characterized by impaired immune responses and systemic low grade chronic inflammation. It has been hypothesized that age-related zinc deficiency may be an important factor contributing to immune dysfunction and chronic inflammation during the aging process. In this review, we discuss the effects of zinc status on aging, potential molecular and epigenetic mechanisms contributing to age-related decline in zinc status, and the role of zinc in age-related immune dysfunction and chronic inflammation.

Zinc supplementation as an adjunct to antibiotics in the treatment of pneumonia in children 2 to 59 months of age

BACKGROUND

Diarrhoeal disorders and acute respiratory infections (ARIs), especially pneumonia, are the most common causes of death in low-income countries. Studies evaluating the impact of zinc supplementation as an adjunct in the management of pneumonia are limited and have shown variable results.

OBJECTIVES

To evaluate zinc supplementation, as an adjunct to antibiotics, in the treatment (clinical recovery) of pneumonia in children aged two to 59 months.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), which contains the Cochrane Acute Respiratory Infections (ARI) Group's and the Cochrane Infectious Diseases Group's Specialised Registers, MEDLINE (1950 to March week 2, 2011), EMBASE (1974 to March 2011), CINAHL (1981 to March 2011), LILACS (1985 to March 2011), AMED (1985 to March 2011), CAB Abstracts (1910 to March 2011) and Web of Science (2000 to March 2011).

SELECTION CRITERIA

Randomised control trials (RCTs) evaluating supplementation of zinc as an adjunct to antibiotics for pneumonia in children aged two to 59 months.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and screened all available titles and abstracts for inclusion. If the relevance could not be ascertained by screening the title and abstract, we retrieved and reviewed the full text of the article.

MAIN RESULTS

We included four trials in which 3267 children aged two to 35 months participated. Analysis showed that zinc supplementation in addition to standard antibiotic therapy in children with severe and non-severe pneumonia failed to show a statistically significant effect on clinical recovery (risk ratio (RR) 1.02; 95% confidence interval (CI) 0.93 to 1.11). Similary, zinc supplementation in children with severe pneumonia, as an adjunct to standard antibiotic therapy, did not show a statistically significant effect on clinical recovery measured as resolution of tachypnoea (respiratory rate > 50 breaths per minute) (RR 1.13; 95% CI 0.82 to 1.57) and cessation of chest indrawing (RR 1.08; 95% CI 0.88 to 1.31) as compared to the control group. Zinc supplementation in children with severe pneumonia also showed a non-significant effect on the duration of hospitalization stay as compared to the control (RR 1.04; 95% CI 0.89 to 1.22).

AUTHORS' CONCLUSIONS

Evidence provided in this review is insufficient to recommend the use of zinc as an adjunct to standard antibiotic therapy for pneumonia in children aged two to 35 months.

Oral rehydration salts, zinc supplement and rota virus vaccine in the management of childhood acute diarrhea

Acute diarrhea remains a major cause of morbidity and mortality in children. Since the introduction of oral rehydration salts (ORS) mortality has dropped to less than 50% worldwide. Low osmolarity ORS improved the outcome and reduced the hospitalization further. Zinc difficiency has been found to be associated with severe episodes of acute diarrhea. Zinc supplement in developing countries did reduce the incidence and prevalence of diarrhea. In addition, Zinc supplement significantly reduced the severity of diarrhea and duration of the episode. In the Americas and Europe, Rota virus vaccine was 90% effective in preventing severe episodes of severe rotavirus gastroenteritis. This review concludes that low osmolarilty ORS, zinc supplementation and rotavirus vaccine are major factors in reducing the morbidity, mortality and hospitalization resulting from to acute gastroenteritis in childhood.

Duration of hospitalization and appetite of HIV-infected South African children

Human immunodeficiency virus (HIV)-infected children generally show poor growth. Episodes of diarrhoea and pneumonia in HIV-infected children are thought to be more severe than in HIV-uninfected children. The objective of this study was to compare duration of hospitalization, appetite and nutritional status of HIV-infected children with that of uninfected children. A cross-sectional study was performed on children (2-24 months) admitted with diarrhoea or pneumonia to the university hospital. Children were tested for HIV, and the duration of hospitalization was noted for 189 children. Follow-up for blood analysis (n=154) and appetite measurement (n=48) was performed 4-8 weeks after discharge. Appetite was measured as ad libitum intake of a commercial infant cereal using highly standardized procedures. Hospitalization (in days) was significantly longer in HIV-infected children; among children admitted with diarrhoea (5.9 ± 1.9 vs. 3.8 ± 1.5) (mean ± standard deviation) and with pneumonia (9.0 ± 2.5 vs. 5.9 ± 1.9). Serum zinc, iron and transferrin concentrations, and haemoglobin levels were significantly lower in HIV-infected children compared with uninfected children. Appetites [amounts eaten (g) per kg body weight] of HIV-infected children were significantly poorer than those of HIV-uninfected children (18.6 ± 5.8 vs. 25.2 ± 7.4). The eating rates (g min(-1) ) of HIV-infected children were also slower (17.6 ± 6.2 vs. 10.1 ± 3.7) Mean Z-scores for length-for-age were significantly lower among HIV-infected children compared with HIV-uninfected children. Weight-for-length Z-scores were not significantly different. In summary, HIV-infected children had a 55% longer duration of hospitalization and a 21% lower appetite.

Zinc supplementation in severe acute lower respiratory tract infection in children: a triple-blind randomized placebo controlled trial

OBJECTIVE

To evaluate the efficacy of zinc supplementation on duration of illness in children with severe acute lower respiratory tract infection (ALRTI).

METHODS

This randomized triple-blind placebo-controlled trial was conducted in pediatric emergency of a teaching referral hospital. Children in the age group of 2-24 months presenting to pediatric emergency with severe ALRTI were included. Eligible children were randomly allocated to zinc (n=53) or control (n=53) groups. Zinc group received 20 mg of elemental zinc per day (5 ml syrup per day) as a single daily dose for 5 days. Control group received an equal amount of placebo which was appropriately modified to give the taste, smell, color and consistency similar to zinc mixture. Primary outcome was 'time to be asymptomatic', a composite outcome defined as resolution of all four of the following: danger signs, respiratory distress, tachypnea and hypoxia in room air.

RESULTS

Age, gender, nutritional status, pretreatment zinc levels and other demographic and clinical variables were similar in the two groups. 'Time to be asymptomatic' was comparable in the two groups (h; median (IQR): 60 (24-78) vs. 54 (30-72), P=0.98]. At any time point a similar proportion of children were symptomatic in both the groups. Time to resolution of respiratory distress, tachypnea, dangers signs and hypoxia were also similar in two groups. Duration of hospital stay was shorter by 9 h in the zinc group but the difference was statistically insignificant.

CONCLUSION

Zinc supplementation did not reduce recovery time and duration of hospital stay in children with ALRTI. Larger randomized controlled trials are needed to evaluate role of zinc in ALRTI.

Zinc supplementation for the prevention of pneumonia in children aged 2 months to 59 months

BACKGROUND

Pneumonia is a leading cause of morbidity and mortality in children younger than five years of age. Most deaths occur during infancy and in low-income countries. Daily regimens of zinc have been reported to prevent acute lower respiratory tract infection and reduce child mortality.

OBJECTIVES

To evaluate the effectiveness of zinc supplementation in the prevention of pneumonia in children aged two to 59 months.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 2), which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to January Week 2, 2010), EMBASE (1974 to January 2010) and LILACS (1985 to January 2010).

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating supplementation of zinc for the prevention of pneumonia in children aged 2 to 59 months of age.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

We included six trials and 7850 participants in the meta-analysis. Analysis showed that zinc supplementation reduced the incidence of pneumonia by 13% (risk ratio (RR) 0.87; 95% confidence interval (CI) 0.81 to 0.94, fixed-effect, six studies) and prevalence of pneumonia by 41% (RR 0.59; 95% CI 0.35 to 0.99, random-effects, one study). On subgroup analysis, we found that zinc reduced the incidence of pneumonia defined by specific clinical criteria by 21% (i.e. confirmation by chest examination or chest radiograph) (RR 0.79; 95% CI 0.0.71 to 0.88, fixed-effect, four studies, n = 4591) but had no effect on lower specificity pneumonia case definition (i.e. age specific fast breathing with or without lower chest indrawing) (RR 0.95; 95% CI 0.86 to 1.06, fixed-effect, four studies, n = 3259).

AUTHORS' CONCLUSIONS

Zinc supplementation in children is associated with a reduction in the incidence and prevalence of pneumonia, the leading cause of death in children.

Essential role of vitamin C and zinc in child immunity and health

With the progressive elimination of dietary protein-energy deficits, deficiencies of micronutrients are emerging as the limiting factors in ensuring children's optimal health. Data from several countries in Asia and Latin America indicate that deficiencies of vitamin C and zinc continue to be at alarming levels. This article reviews the roles of vitamin C and zinc in supporting children's growth and development, with a particular focus on the complementary roles they play in supporting immune functions and combating infections. The contemporary relevance of vitamin C and zinc deficiency in the Asian and Latin American regions, both undergoing a rapid nutritional transition, are also discussed. Overall, there is increasing evidence that deficiency of vitamin C and zinc adversely affects the physical and mental growth of children and can impair their immune defences. Nutrition should be the main vehicle for providing these essential nutrients; however, supplementation can represent a valid support method, especially in developing regions.

Zinc influences innate immune responses in children with enterotoxigenic Escherichia coli-induced diarrhea

Information is limited on the effect of zinc on immune responses in children with diarrhea due to enterotoxigenic Escherichia coli (ETEC), the most common bacterial pathogen in children. We studied the immunological effect of zinc treatment (20 mg/d) and supplementation (10 mg/d) in children with diarrhea due to ETEC. A total of 148 children aged 6-24 mo were followed up for 9 mo after a 10-d zinc treatment (ZT; n = 74) or a 10-d zinc treatment plus 3-mo supplementation (ZT+S; n = 74), as well as 50 children with ETEC-induced diarrhea that were not treated with zinc (UT). Fifty control children (HC) of the same age group from the same location were also studied. Serum zinc concentrations were higher in both the ZT (P < 0.001) and ZT+S groups (P < 0.001) than in the UT group but did not differ from the HC group. We found higher serum complement C3 immediately after zinc administration in both ZT (P < 0.001) and ZT+S (P < 0.001) groups than in the UT group. Phagocytic activity in children in both ZT (P < 0.01) and ZT+S (P < 0.01) groups was greater than in the UT group. However, oxidative burst capacity was lower in zinc-receiving groups (ZT, P < 0.001 and ZT+S, P < 0.001) than in the UT group. The naïve:memory T cell ratio in both ZT (P < 0.05) and ZT+S (P < 0.01) groups was higher than in the UT group from d 2 to 15. Increased responses, including complement C3, phagocytic activity, and changes in T cell phenotypes, suggest that zinc administration enhances innate immunity against ETEC infection in children.

The added benefit of zinc supplementation after zinc treatment of acute childhood diarrhoea: a randomized, double-blind field trial

OBJECTIVES

To determine whether continuing with zinc supplementation after zinc treatment (ZT) of an acute diarrhoea episode will result in additional clinical benefits beyond ZT alone.

METHODS

Children 6-23 months of age, living in an urban slum in Dhaka, Bangladesh with acute childhood diarrhoea (ACD), were enrolled in a randomized, double-blind field trial. All children received 10 days of ZT (20 mg/day) and were then randomized to zinc (10 mg/day) or placebo supplementation for 3 months. Weekly follow-up of all children occurred over a period of 9 months.

RESULTS

A total of 353 subjects were enrolled, with 93% of the zinc supplemented and 96% of the placebo children followed for 9 months. The incidence density of ACD among those receiving zinc supplementation compared to those receiving placebo was reduced by 28% (2.64 vs.3.66 episodes/p-y follow-up) over the 3 months while on supplementation and by 21% (2.05 vs.2.59 episodes/p-y follow-up) over the 9 months of follow-up. There was no observed effect on the incidence of acute respiratory infections (ARIs) or on growth.

CONCLUSIONS

Zinc supplementation after treatment provides additional preventive ACD benefits to children in early childhood. Larger, effectiveness trials of this strategy are warranted.

A new insight into pathophysiological mechanisms of zinc in diarrhea

An increasing amount of data showing the beneficial use of zinc (Zn) in treating diarrhea continues to emerge from epidemiological and clinical trials. However, without a thorough understanding of physiological mechanisms of Zn, it does not support policy recommendation to advocate the therapeutic use of Zn. Our data demonstrate that Zn is a potential antidiarrheal agent that provides substantial benefit by stimulating sodium absorption and inhibiting chloride secretion in intestinal epithelial cells. Thus, inclusion of Zn in oral rehydration solution (ORS) has the potential to markedly augment the effectiveness of ORS in the treatment of diarrhea.

Gastroenterology in developing countries: issues and advances

Developing countries shoulder a considerable burden of gastroenterological disease. Infectious diseases in particular cause enormous morbidity and mortality. Diseases which afflict both western and developing countries are often seen in more florid forms in poorer countries. Innovative techniques continuously improve and update gastroenterological practice. However, advances in diagnosis and treatment which are commonplace in the West, have yet to reach many developing countries. Clinical guidelines, based on these advances and collated in resource-rich environments, lose their relevance outside these settings. In this two-part review, we first highlight the global burden of gastroenterological disease in three major areas: diarrhoeal diseases, hepatitis B, and Helicobacter pylori. Recent progress in their management is explored, with consideration of future solutions. The second part of the review focuses on the delivery of clinical services in developing countries. Inadequate numbers of healthcare workers hamper efforts to combat gastroenterological disease. Reasons for this shortage are examined, along with possibilities for increased specialist training. Endoscopy services, the mainstay of gastroenterology in the West, are in their infancy in many developing countries. The challenges faced by those setting up a service are illustrated by the example of a Nigerian endoscopy unit. Finally, we highlight the limited scope of many clinical guidelines produced in western countries. Guidelines which take account of resource limitations in the form of "cascades" are advocated in order to make these guidelines truly global. Recognition of the different working conditions facing practitioners worldwide is an important step towards narrowing the gap between gastroenterology in rich and poor countries.

Zinc deficiency

PURPOSE OF REVIEW

Zinc plays an essential role in numerous biochemical pathways. Zinc deficiency affects many organ systems, including the integumentary, gastrointestinal, central nervous system, immune, skeletal, and reproductive systems. This article aims to discuss zinc metabolism and highlights a few of the diseases associated with zinc deficiency.

RECENT FINDINGS

Zinc deficiency results in dysfunction of both humoral and cell-mediated immunity and increases the susceptibility to infection. Supplementation of zinc has been shown to reduce the incidence of infection as well as cellular damage from increased oxidative stress. Zinc deficiency is also associated with acute and chronic liver disease. Zinc supplementation protects against toxin-induced liver damage and is used as a therapy for hepatic encephalopathy in patients refractory to standard treatment. Zinc deficiency has also been implicated in diarrheal disease, and supplementation has been effective in both prophylaxis and treatment of acute diarrhea.

SUMMARY

This article is not meant to review all of the disease states associated with zinc deficiency. Rather, it is an introduction to the influence of the many roles of zinc in the body, with an extensive discussion of the influence of zinc deficiency in selected diseases. Zinc supplementation may be beneficial as an adjunct to treatment of many disease states.

Status of essential trace metals in biological samples of diabetic mother and their neonates

OBJECTIVE

There is accumulating facts that the metabolism of essential trace elements is altered in diabetic patients. The aim of present study was to compare the status of essential trace elements, chromium (Cr), manganese (Mn), and zinc (Zn) in biological samples (whole blood, urine and scalp hair) of insulin dependent diabetic mothers (age ranged 30-40) and their newly born infants (n = 76). An age matched 68 non-diabetic mothers and their infants, residing in the same locality, were selected as referents. For a comparative study, the biological samples of non-diabetic and diabetic pregnant and non pregnant of same age group and socio-economics status were also analysed.

METHODOLOGY

The biological samples (scalp hair, blood and urine) were collected from study and referent groups. The Cr, Mn and Zn concentrations in all three biological samples were determined by a flame/electrothermal atomic absorption spectrometer, prior to microwave assisted acid digestion. The validity and accuracy of the methodology was checked by certified reference materials (CRMs) and using conventional wet acid digestion method on same CRMs.

RESULTS

The mean values of Cr, Mn and Zn in scalp hair and blood samples of diabetic mothers and their infants were significantly lower as compared to the referent mothers-infants pairs (p < 0.01), while urinary excretion of all these elements were high in diabetic mother-infant pair samples.

CONCLUSION

The deficiencies of essential trace elements, Cr, Mn and Zn in biological samples of diabetic women, may play role in the pathogenesis of diabetes mellitus and impacts on their neonates.

Functional indicators for assessing zinc deficiency

Zinc is an essential micronutrient for growth and proper immune function. There is currently no simple recommendation for the assessment of population-level zinc deficiency. Trials of zinc supplementation have shown positive effects of supplementation on clinical outcomes and growth. We reviewed the results of randomized trials of zinc supplementation and correlation studies that assessed infectious diseases, growth, and development outcomes among children under 5 years of age. The results indicate that zinc supplementation decreases the incidence and prevalence of diarrhea and pneumonia, but the use of trial data to make population-level estimates of zinc deficiency is not practical and is difficult to quantify. The data also indicate that zinc supplementation increases growth, especially among children who are stunted. Stunting rates are commonly estimated and can be used to estimate zinc deficiency. Previous recommendations suggest that stunting rates at or above 20% should be indicative of zinc deficiency among children under 5 years of age. This review provides additional data and analysis to support the current recommendation.

Undernutrition, infection and immune function

Undernutrition and infection are the major causes of morbidity and mortality in the developing world. These two problems are interrelated. Undernutrition compromises barrier function, allowing easier access by pathogens, and compromises immune function, decreasing the ability of the host to eliminate pathogens once they enter the body. Thus, malnutrition predisposes to infections. Infections can alter nutritional status mediated by changes in dietary intake, absorption and nutrient requirements and losses of endogenous nutrients. Thus, the presence of infections can contribute to the malnourished state. The global burden of malnutrition and infectious disease is immense, especially amongst children. Childhood infections impair growth and development. There is a role for breast-feeding in protection against infections. Key nutrients required for an efficient immune response include vitamin A, Fe, Zn and Cu. There is some evidence that provision of the first three of these nutrients does improve immune function in undernourished children and can reduce the morbidity and mortality of some infectious diseases including measles, diarrhoeal disease and upper and lower respiratory tract infections. Not all studies, however, show benefit of single nutrient supplementation and this might be because the subjects studied have multiple nutrient deficiencies. The situation regarding Fe supplementation is particularly complex. In addition to immunization programmes and improvement of nutrient status, there are important roles for maternal education, improved hygiene and sanitation and increased supply of quality water in the eradication of infectious diseases.

Serum zinc and pneumonia in nursing home elderly

BACKGROUND

Zinc plays an important role in immune function. The association between serum zinc and pneumonia in the elderly has not been studied.

OBJECTIVE

The objective was to determine whether serum zinc concentrations in nursing home elderly are associated with the incidence and duration of pneumonia, total and duration of antibiotic use, and pneumonia-associated and all-cause mortality.

DESIGN

This observational study was conducted in residents from 33 nursing homes in Boston, MA, who participated in a 1-y randomized, double-blind, and placebo-controlled vitamin E supplementation trial; all were given daily doses of 50% of the recommended dietary allowance of essential vitamins and minerals, including zinc. Participants with baseline (n = 578) or final (n = 420) serum zinc concentrations were categorized as having low (<70 microg/dL) or normal (>or=70 microg/dL) serum zinc concentrations. Outcome measures included the incidence and number of days with pneumonia, number of new antibiotic prescriptions, days of antibiotic use, death due to pneumonia, and all-cause mortality.

RESULTS

Compared with subjects with low zinc concentrations, subjects with normal final serum zinc concentrations had a lower incidence of pneumonia, fewer (by almost 50%) new antibiotic prescriptions, a shorter duration of pneumonia, and fewer days of antibiotic use (3.9 d compared with 2.6 d) (P <or= 0.004 for all). Normal baseline serum zinc concentrations were associated with a reduction in all-cause mortality (P = 0.049).

CONCLUSION

Normal serum zinc concentrations in nursing home elderly are associated with a decreased incidence and duration of pneumonia, a decreased number of new antibiotic prescriptions, and a decrease in the days of antibiotic use. Zinc supplementation to maintain normal serum zinc concentrations in the elderly may help reduce the incidence of pneumonia and associated morbidity.

Can zinc be an adjuvant therapy for juvenile onset recurrent respiratory papillomatosis?

OBJECTIVES

To report a severe case of juvenile onset recurrent respiratory papillomatosis (JORRP) controlled by zinc replacement therapy. To review the contemporary adjuvant therapies used in JORRP.

METHODS

The trial of zinc was described in terms of its effect on the inter-surgical interval, site score and clinical symptoms. Long-term follow-up with dose adjustment was detailed. Articles reporting trials of adjuvant therapies over the past 20 years were reviewed in terms of regimen used, mode of assessment, side effects and final outcome.

RESULTS

Zinc was effective in decreasing the severity of the disease, the rate of relapse and the need for surgery. There was an obvious relation between the dose used and the degree of improvement. Prolonged treatment seems to be needed to sustain the positive effect. No side effects were noticed over a 45-month follow-up period. The literature does support the role of zinc in modulating the immune system. Eight adjuvant therapies were reviewed as published in 40 reports. Interferon was the most used substance. It is definitely effective but often associated with relapse upon discontinuation. The effect of cidofovir was favorable yet not dramatic as initially expected. Other less commonly used therapies showed humble effects. The HspE7 vaccine seems to be promising awaiting further trials.

CONCLUSIONS

Zinc replacement therapy may benefit JORRP patients with zinc deficiency and should be investigated in more cases. Several adjuvant therapies are available for use in JORRP. They are generally beneficial though mostly not curative.

Serum zinc levels in children with acute gastroenteritis

BACKGROUND

The aim of the present study was to determine the serum zinc levels on admission and 7-10 days after clinical recovery from acute gastroenteritis of <8 days' duration.

METHODS

This prospective study included 82 infants aged 2-24 months who had no associated bacterial infection, chronic disease, prior antibiotic use, moderate or severe malnutrition or dysentery. Forty-one healthy children formed the control group.

RESULTS

The mean serum zinc level on admission (Zn1) was 11.85 +/- 2.83 micromol/L and at 7-10 days after recovery (Zn2) was 10.92 +/- 2.17 micromol/L; mean serum zinc level of the control group was 11.81 +/- 3.45 micromol/L. Zn2 was significantly lower than Zn1, but there was no statistical difference between the mean of the control group and Zn1 and Zn2. When dehydrated patients were excluded from the patient group, Zn1 and Zn2 did not differ. Although asymptomatic, 39% of the control group had low zinc. Serum zinc levels were not affected by sex, age, clinical characteristics of the patients or severity of gastroenteritis.

CONCLUSION

Serum zinc levels of the patients admitted with acute gastroenteritis without any other disease and without moderate or severe malnutrition were not affected by disease state. Gastroenteritis did not further decrease serum zinc levels in patients with asymptomatic or subclinical zinc deficiency.

Zinc status of Iranian preschool children

BACKGROUND

Zinc deficiency is one of the most prevalent micronutrient deficiencies in developing countries, including Iran. The main direct causes of zinc deficiency are insufficient zinc intake, absorption or metabolic disorder, and increase in need during acute growth periods.

OBJECTIVE

To determine the prevalence of zinc deficiency in preschool boys and girls in urban and rural populations in order to assist policy makers. Children of preschool age (i.e., 6 years old in Iran) were studied because interventions in this age group are believed to result in greater improvement in learning skills once these children enter school.

METHODS

A national cross-sectional study was carried out on 4,374 randomly selected healthy preschool children from Iranian families in 2001. Serum zinc concentration was measured by atomic absorption spectrometry. The cutoff point for zinc deficiency was set at a serum level of 10 micromol/L (65 microg/dL).

RESULTS

The prevalence of zinc deficiency was estimated at approximately 19.3%. The highest prevalence was seen in the region that includes Sistan and Baluchistan, South Khorasan, and the southeast area of Kerman and the lowest in the region of Boushehr, Hormozgan, and South Khoozestan. The prevalence of zinc deficiency was significantly higher in rural areas than in urban areas. No significant difference in prevalence was seen between boys and girls.

CONCLUSIONS

In the long run, nutritional security and increased access to and intake of foods with high levels of zinc are the most sustainable strategies to overcome zinc deficiency. Fortification of staple foods, improved quality of traditional bread, and supplementation for at-risk population groups are considered short- and mid-term interventions. Nutrition education and behavioral change may be long-term strategies.

Effect of Zinc Supplementation on the Immune Status of Healthy Older Individuals Aged 55-70 Years: The ZENITH Study

Aging is associated with alterations in the immune system, effects which may be exacerbated by inadequate zinc (Zn) status. We examined the relationship between Zn status and markers of immunity and the effect of supplementation with 15 mg or 30 mg Zn/d for 6 months on immune status in healthy individuals. Zn status was assessed by dietary intake and biochemical indices. Immune status was assessed by multiple flow cytometric methods. At baseline, Zn concentration was positively associated with lymphocyte subpopulation counts and T-lymphocyte activation. Zn supplementation of 30 mg/d significantly lowered B-lymphocyte count, albeit at month 3 only. Lower doses of Zn (15 mg Zn/d) significantly increased the ratio of CD4 to CD8 T lymphocytes at month 6. Overall, these findings suggest that total Zn intake (diet plus supplementation) of up to 40 mg Zn/d do not have significant long-term effects on immune status in apparently healthy persons aged 55-70 years.

Zinc, iron, and lead: relations to head start children's cognitive scores and teachers' ratings of behavior

The objective of this study was to conduct a preliminary investigation of lead, zinc, and iron levels in relation to child cognition and behavior in a small sample of Head Start children. The design was cross-sectional and correlational. Participants were 42 3- to 5-year-old children attending rural Head Start centers. Nonfasting blood samples of whole blood lead, plasma zinc, and ferritin were collected. Teachers rated children's behavior on the California Preschool Social Competency Scale, Howes' Sociability subscale, and the Preschool Behavior Questionnaire. Children were tested individually with the McCarthy Scales of Children's Abilities. Hierarchical regression analyses revealed that zinc and ferritin jointly explained 25% of the variance in McCarthy Scales of Children's Abilities verbal scores. Lead levels explained 25% of the variance in teacher ratings of girls' sociability and 20% of the variance in teacher ratings of girls' classroom competence. Zinc levels explained 39% of the variance in teacher ratings of boys' anxiety. Univariate analysis of variance revealed that the four children low in zinc and iron had significantly higher blood lead (median=0.23 micromol/L [4.73 microg/dL]) than the 31 children sufficient in zinc or iron (median=0.07 micromol/L [1.54 microg/dL]) or the 7 children sufficient in both (median=0.12 micromol/L [2.52 microg/dL]), suggesting an interaction among the three minerals. Within this small low-income sample, the results imply both separate and interacting effects of iron, zinc, and lead. They underscore the importance of studying these three minerals in larger samples of low-income preschool children to make more definitive conclusions.

Zinc status in infantile wheezing

The increase in prevalence of asthma is strongly dependent on environmental factors, including diet. Significant decreases in the intake of dietary zinc may be an important contributing factor to the increasing incidence of wheezing and asthma, but there have been no studies evaluating zinc levels in wheezy infants. Our objective was to investigate the zinc status of wheezy infants. Wheezy infants (n = 34) and healthy children (n = 14) were included in the study. Total IgE and eosinophil counts were obtained, and skin testing was done with a battery of 25 antigens with appropriate positive and negative controls. Levels of zinc were determined in hair, using a Polarized Zeeman Atomic Absorption Spectrophotometer (Hitachi Z-800). No significant difference was observed in peripheral blood eosinophil counts and total IgE levels among groups (P > 0.05). Hair zinc levels were significantly lower in wheezy infants (P < 0.001). In conclusion, hair zinc levels were lower in wheezy infants than in healthy controls, suggesting that zinc deficiency may influence the risk of wheezing in early childhood.

Zinc in the treatment of acute diarrhea: current status and assessment

The improved treatment of acute diarrhea in children during the past 35 years has reduced its morbidity and mortality substantially. However, better therapy still is required. This article reviews the role of oral rehydration solution in the treatment of acute diarrhea with particular attention to recent efforts to develop improved oral rehydration solution formulations. One promising approach is the administration of Zinc (Zn). Based on its beneficial effects in infections, including pneumonia, Zn has been shown to be effective in the treatment of acute diarrhea in several randomized controlled trials including subsequent meta-analyses. Thus, an emerging body of clinical data indicates that Zn can be useful for treating acute diarrhea. However, only limited information is known about the mechanism(s) by which Zn reduces diarrhea. Recent studies have indicated that Zn acts as a K channel blocker of adenosine 3',5'-cyclic monophosphate-mediated chlorine secretion, but may not affect either Ca2+- or guanosine 3',5'-cyclic monophosphate-mediated chlorine secretion. These data provide a strong rationale for further trials testing its efficacy in specific clinical settings and for more detailed physiologic studies examining how Zn exerts its antidiarrheal effect.

Zinc status and age-related changes in peripheral blood leukocyte subpopulations in healthy men and women aged 55-70 y: the ZENITH study

OBJECTIVE

To determine zinc status and age-related changes in the immune function of healthy late-middle-aged men and women (aged 55-70 y).

DESIGN

Observational study.

SETTING

Population of Northern Ireland.

SUBJECTS

Apparently healthy, free-living individuals (45 men, 48 women) aged 55-70 y.

INTERVENTION

Zinc status markers were analysed by flame atomic absorption spectrometry and commercially available kits. Immune function was assessed by flow cytometry.

RESULTS

Serum and erythrocyte zinc concentrations were 13.0 (s.d. 1.40) micromol/l and 222 (s.d. 48.2) micromol/l, respectively. Serum alkaline phosphatase (ALP) concentrations were 76.8 (s.d. 16.1) U/l; women showed significantly higher concentrations of ALP (P = 0.011). Women demonstrated (1) a significant inverse correlation in naive T lymphocytes, specifically naive T-helper lymphocytes (% expression, r = -0.364, P = 0.007 and absolute count, r = -0.275, P = 0.036) with age and (2) a significant positive correlation between late activation of T lymphocytes (% expression, r = 0.299, P = 0.019 and absolute count, r = 0.260, P = 0.039) with advancing age. Men demonstrated a significant positive correlation in the % expression of (CD3-/CD16+/CD56+) natural killer (NK) cells with age (r = 0.316, P = 0.017).

CONCLUSIONS

Between the ages of 55 and 70 y, healthy individuals experience significant alterations in immune function; however, such changes appear largely sex specific. Given the reported importance of adequate zinc status in maintaining optimal immune function, further studies are required to explore the effect of enhanced zinc status on emerging immune deficiencies in cell-mediated immunity in healthy 55-70 y olds.

Zinc and infection: a review

Dietary zinc deficiency is widespread in developing countries and is often aggravated by intercurrent acute and chronic infections. Recent studies have demonstrated that zinc supplementation can significantly reduce the morbidity and mortality of apparently well-nourished children and shorten the time to recovery from acute infectious diseases. This review summarises current knowledge of the role of zinc in childhood diarrhoea, acute respiratory infections and malaria, and its potential role in diseases associated with impaired cellular immunity, namely tuberculosis, lepromatous leprosy and leishmaniasis, and explores avenues for future research.

Impact of the mother's zinc deficiency on the woman's and newborn's health status

The results of studying the prevalence of zinc deficiency in pregnant women and children at birth are presented. About 77% of the mothers and, in average, every third-fifth child depending on gestational age at birth have decreased serum zinc concentration (below 13 micromol/L). Malnutrition regarding macro- and micronutrients increases the risk of zinc deficiency in examined women (AP = 28%; RR = 1.4; CI = 0.9-3.5). Zinc deficiency increases the risk of pregnancy complications, exacerbations of chronic diseases with gestation as background, labor activities disorders, with hypogalactia and decreasing zinc concentration in the breast milk as concomitant conditions. A relationship between the mothers' serum zinc concentration and trace element concentration in umbilical blood, body height and body mass, adaptive possibilities and child morbidity at birth has been established. Children in their first year of life with a zinc concentration in umbilical blood below 13 micromol/L are characterized by reduced rate of linear growth, delay of psycho-motor development and increased morbidity.