International Zinc Nutrition Consultative Group Research Articles

A Systematic Review and Meta-analysis on the Prevalence of Zinc Deficiency in Iranian Population

Objectives: This study aims to assess the zinc deficiency prevalence in Iran during the past two decades and compare it with other countries. Methods: We searched PubMed, Google Scholar, Web of Sciences, Scientific Information Database (SID), and Magiran for English and Persian reports on zinc deficiency prevalence in Iran. The search terms were “zinc”, zinc deficiency”, “low zinc level”, “low zinc concentration”, “prevalence”, “epidemiology”, “status”, “Iran”, “Iranian”, and “Persian”, using Boolean operators ‘AND’ or ‘OR.’ The preferred reporting items for systematic reviews and meta-analysis (PRISMA) checklist were applied during the review. Two authors reviewed the articles independently. We included all articles published from 2001 to 2021 that reported zinc deficiency prevalence based on serum zinc levels (μg/dL) in the Iranian population. We excluded clinical intervention studies and studies on pregnant women, children with stunting or malnutrition, and patients with a particular disease. The effect sizes of prevalence rates were extracted from original studies. Meta-analysis with the random-effects model was used to estimate the pooled prevalence of zinc deficiency. Publication bias was evaluated by Egger’s test and the Funnel plot. Results: This systematic review and meta-analysis included 20 studies (12 for males, 13 for females, and 18 for both that involved 16138 participants; 8424 males and 9053 females). Using the random effect model, the overall prevalence of zinc deficiency in the general population was 16% (95% CI, 11%-20%), and in males and females, 18.4% (95% CI, 0.12%-0.24%) and 15% (95% CI, 10%-20%), respectively. In subgroup analysis, the prevalence rates of zinc deficiency for 6 years old children and adolescents were 29% and 12%, respectively. Conclusions: The overall prevalence of zinc deficiency in the Iranian population was 16%, lower than the 20% set by IZiNCG (the International Zinc Nutrition Consultative Group) to indicate the need for national intervention programs. However, the COVID-19 pandemic and climate changes threaten this fragile margin. Dietary diversification/modifications, supplementation programs, fortification, and bio-fortification can be used to minimize the problem in high-risk populations. Since this study evaluates the adult healthy population of Iran, we should be cautious about generalizing its results on other population groups like children.

Applying Zinc Nutrient Reference Values as Proposed by Different Authorities Results in Large Differences in the Estimated Prevalence of Inadequate Zinc Intake by Young Children and Women and in Cameroon.

Nutrient reference values (NRVs) for zinc set by several expert groups differ widely and may affect the predicted prevalence of inadequate zinc intake. We examined this possibility using NRVs published by four different authorities and nationally representative dietary intake data collected among children aged 12–59 months and women in Cameroon. Usual zinc intake was estimated from 24 h recall data using the National Cancer Institute method. Prevalences of total zinc intake below the dietary requirement and of “absorbable zinc intake” below the physiological requirement were estimated using NRVs published by the World Health Organization (WHO), US Institute of Medicine (IOM), International Zinc Nutrition Consultative Group (IZiNCG), and European Food Safety Authority (EFSA). The prevalence of inadequate zinc intake ranged from 10% (IZiNCG—physiological requirement, 95% CI 7–13%) to 81% (EFSA—physiological requirement, 95% CI 78–84%) among children and 9% (WHO—physiological requirement, 95% CI 8–11.0%) to 94% (IOM—physiological requirement, 95% CI 92–95%) among women These differences in the prevalence of inadequate intake translated into sizeable differences in the predicted benefit and cost-effectiveness of zinc fortification programs. Depending on the NRVs applied, assessments differ regarding the need for and design of zinc fortification programs. Efforts are needed to harmonize NRVs for zinc.

Reference cut-offs to define low serum zinc concentrations in healthy 1-19 year old Indian children and adolescents.

Population zinc (Zn) status assessment is based on serum zinc concentration (SZC) cut-offs defined by the International Zinc Nutrition Consultative Group (IZiNCG). The objective of this study is to derive reference SZC cut-offs in apparently healthy 1-19 year Indian children and adolescents using comprehensive national nutrition survey (CNNS) data, and to measure the prevalence of Zn deficiency. Apparently healthy children (n = 12,473) were selected from the CNNS, by including the highest 2 wealth quintiles, and excluding stunted, thin and obese children, and those with CRP > 5 mg/L, anaemia, hypo-albuminemia, diabetes, recent diarrhoea and history of smoking. The 2.5th centile of age-based distributions defined the SZC cut-offs, used to measure the prevalence of Zn deficiency in India, as against the IZiNCG cut-offs. The present study SZC cut-offs were significantly lower, by 10-18 µg/dL, than the IZiNCG cut-offs; more in adolescents. Prevalence of Zn deficiency in the entire CNNS, with these cut-offs, was 2.7 (<10 years) to 5.5 (10-19 years) times lower than with the IZiNCG cut-offs. No geographical state, nor any age group, had Zn deficiency as a serious public health problem (≥20%). In contrast, with IZiNCG cut-offs, 9-27 states (depending on age group) had a public health problem. The present study reference SZC cut-offs for Zn deficiency are lower than the IZiNCG cut-offs, and their rigorous selection from a national sample makes them more appropriate for use in India. A re-examination of the global applicability of IZiNCG recommended cut-offs in other LMICs appears appropriate.

Assessment of zinc inadequacy among tribal adolescent population of central India - A cross-sectional study.

Zinc is a crucial micronutrient in adolescence, required for promoting growth and sexual maturation. Adolescents of some tribes may be at high risk of zinc deficiency due to dietary inadequacy and poor bioavailability of zinc from plant-based diets. This study aimed to evaluate the risk of zinc deficiency by estimating prevalence of inadequate zinc intake, prevalence of low serum zinc and stunting among tribal adolescents. A cross-sectional community-based survey was conducted among adolescents (10-19 yr) in three purposively selected districts where Bhil, Korku and Gond tribes were in majority. Structured data collection instrument comprising information about sociodemographic characteristics and dietary recall data was used. Anthropometric assessment was conducted by standardized weighing scales and anthropometry tapes, and blood sample was collected from antecubital vein into trace element-free vacutainers. Serum zinc was estimated using an atomic absorption spectrophotometer. A total of 2310 households were approached for participation in the study, of which 2224 households having 5151 adolescents participated. Out of these enlisted adolescents, 4673 responded to dietary recall (90.7% response rate). Anthropometry of 2437 participants was carried out, and serum zinc was analyzed in 844 adolescents. The overall prevalence of dietary zinc inadequacy was 42.6 per cent [95% confidence interval (CI) 41.2 to 44.1] with reference to the estimated average requirement suggested by International Zinc Nutrition Consultative Group (IZiNCG) and 64.8 per cent (95% CI 63.4 to 66.2) with Indian Council of Medical Research-recommended requirements. Stunting was observed in 29 per cent (95% CI 27.2 to 30.8) participants. According to IZiNCG cut-offs, low serum zinc was detected in 57.5 per cent (95% CI 54.1 to 60.8) of adolescents, whereas it was 34.4 per cent (95% CI: 31.2-37.5) according to the national level cut-off. Risk of dietary zinc inadequacy and low serum zinc concentration amongst adolescents of the Gond, Bhil and Korku tribes is a public health concern.

Prevalence and Correlates of Zinc Deficiency Among Vietnamese Women of Reproductive Age in Ho Chi Minh City: A Single Hospital-Based Survey.

Background and Objectives: Zinc is a micronutrient that plays an important role in metabolism, cell growth regulation, and differentiation. Vietnam has many population groups living in poverty. The daily food of Vietnamese people is mainly rice, which contains very little zinc. This cross-sectional study was conducted to determine the prevalence of, and factors related to, zinc deficiency in women of reproductive age.Methods and Study Design: The sample population was non-pregnant women of reproductive age (18–49 years old) who visited Nguyen Tri Phuong Hospital Gynecological Outpatient Clinic. The subjects were interviewed and data on background characteristics, anthropometric measurements, and blood tests (serum zinc concentration, complete blood count, albumin, and ferritin) were collected.Results: The prevalence of zinc deficiency, as defined by the International Zinc Nutrition Consultative Group (IZiNCG), was 85% [61/72; 95% confidence interval (CI) = 74–91%], and the prevalence of severe zinc deficiency was 37% (27/72; 95% CI = 26–50%). There were significant associations of albumin concentration, marital status, and past pregnancy history with severe zinc deficiency.Conclusions: More than three-fourths of Vietnamese women of reproductive age had zinc deficiency at our study site in Ho Chi Minh City. This health issue requires greater attention in order to swiftly promote preventive actions, and further surveillance to confirm our study findings.

Prevalence of low serum zinc concentrations in Indian children and adolescents: findings from the Comprehensive National Nutrition Survey 2016–18

It is thought that there is a high risk of zinc deficiency in India, but there are no representative national estimates. We aimed to evaluate the national and state-level prevalence of low serum zinc concentrations (SZCs) in Indian children from the nationally representative Comprehensive National Nutrition Survey. Prevalence of low SZC, adjusted for C-reactive protein, was estimated among preschool (1-4 y; n=7874) and school-age children (5-9 y; n=10,430) and adolescents (10-19 y; n=10,140), using SZC cutoffs defined by the International Zinc Nutrition Consultative Group. Prevalence of low SZC was high among adolescents (31.1%; 95% CI: 29.8%, 32.4%), compared with school-age (15.8%; 95% CI: 15.3%, 16.3%) or preschool children (17.4%; 95% CI: 16.7%, 18.0%). However, stratification of prevalence by fasting status or using an alternative lower SZC cutoff independent of fasting status led to a reduction in prevalence by 3.7% or 7.8% in children <10 y, respectively. The prevalence of low SZC was higher among rural preschool children, those belonging to households with poor socioeconomic status, and those with severe stunting or underweight. Preschool children with diarrhea (22.6%; 95% CI: 20.8%, 24.4%), productive cough (22.7%; 95% CI: 18.5%, 27.5%), or malaria/dengue (38.5%; 95% CI: 29.4%, 48.2%) in the 2 wk preceding the survey had a higher prevalence of low SZC than those without morbidity (16.5%; 95% CI: 15.9%, 17.2%; 17.6%; 95% CI: 16.9%, 18.2%; and 17.5%; 95% CI: 16.8%, 18.1%, respectively). The national prevalence of low SZC among preschool (17%) or school-age children (16%) was <20%, which is considered the cutoff indicating a problem of public health significance; but there were variations by state and socioeconomic status. In adolescents, however, the prevalence of low SZC was 31%, which warrants further investigation. The association of low SZC with diarrhea in preschool children necessitates better coverage of Zn administration in the management of diarrhea.

Serum zinc status is a matter of concern among children and non-pregnant women in a nationwide survey of Nepal

Nationally representative population data on zinc status in Nepal is lacking at present. This study analyzed data from the recent Nepal National Micronutrient status survey 2016 to determine the prevalence of zinc deficiency and associated risk factors among children aged 6–59 months (n = 1462) and non-pregnant women aged 15–49 years (n = 1923). Venous blood was collected from the participants to measure micronutrients such as zinc, markers of anemia, RBP (vitamin A), and markers of inflammation. Stool samples were collected to assess soil-transmitted helminths and Helicobacter pylori infection. Socio-demographic, household, and other relevant factors were collected by a structured questionnaire. Serum zinc concentration was measured by Microwave Plasma Atomic Emission Spectrometry, and zinc deficiency was defined according to the International Zinc Nutrition Consultative Group’s guidelines. Logistic regression was used to examine the predictors of zinc deficiency among the participants. The overall zinc deficiency in children was 22.9%, while it was higher in non-pregnant women (24.7%). The prevalence of anemia among zinc-deficient children was higher (21.3%) than the zinc non-deficit children (18.7%). The prevalence of anemia was 18% among zinc-deficient non-pregnant women compared to 22% non-deficit non-pregnant women. Predictors associated with zinc deficiency among the study children were living in rural areas (AOR = 2.25, 95% CI, [1.13, 4.49]), the occurrence of diarrhea during the two weeks preceding the survey (AOR = 1.57, 95% CI, [1.07, 2.30]), lowest household wealth quintile (AOR = 0.48, 95% CI, [0.25, 0.92]) and lower vitamin A status (AOR = 0.49, 95% CI, [0.28, 0.85]. The predictors associated with zinc deficiency among non-pregnant women were: being underweight (AOR = 1.55, 95% CI, [1.12, 2.15]), fever occurrence during two weeks preceding the survey (AOR = 1.43, 95% CI, [1.04, 1.98]), H. pylori in the stool (AOR = 1.33, 95% CI, [1.04, 1.71]), lowest household wealth quintile (AOR = 0.62, 95% CI,[0.40, 0.94]) and being at risk of folate deficiency (AOR = 0.58, 95% CI,[0.36, 0.94]). We conclude that community-level intervention programs focused on rural children and women to prevent diarrhea, improve nutrition counseling, and provide economic opportunities in rural communities may help to lower zinc deficiency and other micronutrient deficiencies in the Nepalese population. We believe that intervention programs to address zinc deficiency should not be isolated. Instead, integrated approaches are beneficial to improve overall micronutrient status, such as encouraging dietary diversity, providing livelihood opportunities to the unemployed, micronutrient supplementation to vulnerable populations, and consumption of zinc-rich animal-based foods.

Evaluation of Serum Zinc Status of Pregnant Women in the China Adult Chronic Disease and Nutrition Surveillance (CACDNS) 2015.

Objective: The purpose of this study was to evaluate serum zinc status of pregnant women in the China Adult Chronic Disease and Nutrition Surveillance (CACDNS) in 2015–2016. Methods: A total of 7147 apparently healthy pregnant women were randomly selected in 302 national monitoring sites. Information on age, race, residence region, education, pregnancy, and family income per annum was collected, and the concentration of serum zinc was determined. The evaluation of serum zinc status was further performed according to the recommendations by the International Zinc Nutrition Consultative Group (IZiNCG). Results: The median concentration of serum zinc was 858.9 μg/L with an interquartile range (IQR) of 712.9 μg/L and 1048.9 μg/L, while the overall prevalence of zinc deficiency was 3.5% with a 95% confidence interval (CI) of 3.0% and 3.9%. Serum zinc status of pregnant women changed greatly in the different categories, particular in pregnancy and family income per annum (p < 0.05), but no significant difference was observed in the prevalence of zinc deficiency (p > 0.05). Conclusions: The lower prevalence of zinc deficiency generally indicated a better zinc status for pregnant women in the CACDNS in 2015–2016. However, a well-designed evaluation system of zinc status for pregnant women should be continually optimized and improved by inducing more parameters such as biochemical, dietary, or functional indicators.

Reference Cut-Offs to Define Low Serum Zinc Concentrations in 1-19 Year Old Indian Children and Adolescents

Background: The quantification of population zinc (Zn) deficiency is based on serum zinc concentration (SZC) cut-offs, defined by International Zinc Nutrition Consultative Group (IZiNCG), derived from the 2·5th centile of age- and sex-specific SZC distributions from a high-income country. However, the SZC distributions, and its 2·5tthcentile cut-offs, can left-shift for a variety of reasons in lower middle-income countries (LMICs). The recent quality-controlled Indian Comprehensive National Nutrition Survey (CNNS) offered an opportunity to re-examine the SZC cut-offs in healthy 1–19-year-old children and adolescents and evaluate whether Zn deficiency was truly a public health problem in India. Methods: A healthy population (n=12473) of children was selected by including the highest 2 wealth quintiles, and excluding stunted, thin and obese children, and those with CRP >5mg/L, anemia, hypo-albuminemia, diabetes, recent diarrhea and a history of smoking. The 2·5th centile of the SZC distribution from this sample yielded the present cut-off to re-evaluate the prevalence of Zn deficiency against the IZiNCG cut-offs. Findings: The present study SZC cut-offs were significantly lower, by 10–18 µg/dL, than the IZiNCG cut-offs; more in adolescents. Thus, the prevalence of Zn deficiency in the entire CNNS sample, with the present cut-offs, was 2·7 to 5·5 times lower than with the IZiNCG cut-offs. No geographical state, nor any age group, showed Zn deficiency as a serious public health problem (≥20%). In contrast, with the IZiNCG cut-offs, between 9 to 27 states (depending on age group) had a serious public health problem with Zn deficiency. Interpretation: The present study reference SZC cut-offs for Zn deficiency are lower than the IZiNCG cut-offs, and since they were selected rigorously from a national sample, are more appropriate for use in India. A re-examination of the global applicability of IZiNCG recommended cut-offs to quantify Zn deficiency in other LMICs is required. Funding Source: CNNS is funded by The Mittal Foundation. However, there is no specific funding for this secondary analysis. Declaration of Interests: HSS designed the draft protocol of the CNNS with consultancy support from UNICEF, India. HSS, UK, and AVK were members of the Technical Advisory Committee of the CNNS, constituted by the Ministry of Health and Family Welfare of the Government of India, to oversee its conduct and analysis. HSS is a member of the WHO Nutrition Guidance Expert Advisory Subgroup on Diet and Health and Guideline Development Group on the use and interpretation of haemoglobin concentrations for assessing anaemia status in individuals and populations, member of the World Health Organization Nutrition Guidance Expert Advisory Subgroup on Diet and Health and Expert group on nutrient requirements: setting calcium, vitamin D and Zn nutrient intake values for children aged 0-4 years. He is also member of Expert Groups of the Ministry of Health and Family Welfare on Nutrition and Child Health. SD was involved in the CNNS study implementation. There were no other conflicts to declare. Ethics Approval Statement: The Population Council’s International Review Board (New York, USA) and the Ethics Committee of the Post Graduate Institute of Medical Education and Research (Chandigarh, India) gave ethical approval. Written consent from parent/caregiver for children under 10 years, consent of parent/caregiver as well as assent from adolescents (11-17 years) and written consent of adolescents above 17 years were obtained after due description of study details in local languages.

Trends in the national food supply of absorbable zinc in Ethiopia: 1990-2017.

This study analysed trends (1990-2017) in the availability of absorbable Zn in the national food supply of Ethiopia. The supply statistics of ninety-five food groups were obtained from the Ethiopian Food Balance Sheets compiled by FAO. Zn and phytate contents were determined using multiple composition databases and absorbable Zn estimated via the 'Miller' equation. Estimated average requirement cut-point method was performed to estimate proportions at risk of inadequate intake. Physiological Zn requirements set by Institute of Medicine (IOM) and International Zinc Nutrition Consultative Group (IZiNCG) were applied. Time trend was tested using Mann-Kendall statistics and Z-score and P-values are provided. Ethiopia. NA. Between 1990 and 2017, the supply of total dietary Zn was increased by 33 % from 9·8 to 13·0 mg/person/d (Z = 6·46, P < 0·001). However, that of absorbable Zn remained constant around 2·7 mg/person/d (Z = 1·87, P > 0·05). Over the period, the phytate supply was increased by 48 % from 1415 to 2095 mg/person/d (Z = 6·50, P < 0·001) and fractional Zn absorption declined from 27·0 to 20·9 % (Z = -6·62, P < 0·001). The contribution of animal source foods for bioavailable Zn was reduced by 45 % and the share of cereals raised by 11·3 %. Over the period, prevalence of inadequate Zn intake estimated using IZiNCG and IOM requirements remained constant around 10 and 50 %, respectively. Between 1990 and 2017, Ethiopia considerably increased the total supply of Zn; however, meaningful changes in bioavailable Zn and prevalence of deficiency were not observed due to proportional rise in phytate and concomitant decline in Zn absorption.

Association between Phytate Intake and C-Reactive Protein Concentration among People with Overweight or Obesity: A Cross-Sectional Study Using NHANES 2009/2010.

Phytic acid has anti-oxidant properties, which are useful in addressing inflammation. This study investigated the relationship between dietary phytate intake and C-reactive protein (CRP) levels among individuals that are overweight or obese. The study used cross-sectional data from the 2009/2010 National Health and Nutrition Examination Survey (NHANES) for 3152 subjects. Phytate intake was estimated using phytate content of foods reported by the International Zinc Nutrition Consultative Group (IZiNCG). Logistic regression was used to determine the associations between phytate intake and odds of elevated CRP concentration (CRP >3 mg/L), adjusting for confounders. Medians (and 95% CIs) for phytate intake and CRP concentration were 0.66 (0.64, 0.68) g/d and 1.4 (1.2, 1.5) mg/L, respectively. Phytate intake was higher in males than females, higher in non-Hispanic Whites than non-Hispanic Blacks and Mexican Americans, and lower in current smokers than former smokers and nonsmokers. Higher phytate intake was associated with lower odds of elevated CRP (OR = 0.66; 95% CI = 0.52, 0.84). Women, as well as current and former smokers with overweight or obesity, had higher odds of elevated CRP concentration. These results imply that individuals with high phytate intake, particularly among those with overweight or obesity, have lower risk for inflammation-related chronic diseases such as cardiovascular diseases.

Is zinc deficiency a worldwide problem and is there a silent epidemic in Saudi Arabia?

Background: Zinc is an important trace mineral for our body, the deficiency of which can cause many complications like inadequate or stunted growth, immune deficiency with increased morbidity, etc. As per literature, in more severe cases, zinc deficiency causes hair loss, diarrhea, delayed sexual maturation, impotence, hypogonadism in males, and eye and skin lesions. Weight loss, delayed healing of wounds, taste abnormalities, and mental lethargy can also occur. Therefore, it is important that Zinc levels should be done especially when even any of the above nonspecific symptoms and signs are present. Zinc absorption is inhibited by phytates (seen in cereals, rice, corn, etc), cadmium (from environment), etc and this is an important factor to be considered apart from Zinc intake ,etc. A "best-estimate" model, comprised of zinc and phytate data from a composite nutrient database and International Zinc Nutrition Consultative Group physiological requirements for absorbed zinc, estimated the global prevalence of inadequate zinc intake to be 17.3%. Range varied from 12-66 % with different methodologies. Aim: To determine the prevalence of Zinc deficiency in the MEDICAL PROTOCOL DEPARTMENT- OUT-PATIENT CLINIC at King Fahad Hospital-National Guard Health Affairs-Riyadh, KSA. Methods: About 1000 patients of both genders between the ages of 15 -90 &amp; above over a period of 6 months (in 2013) of our regular out-patient clinic were tested for Zinc deficiency irrespective of any signs or symptoms. Results: Out of 1000 patients about 440 (44%) patients were low in Zinc levels and treated for Zinc deficiency Conclusions: 1. There is a high prevalence of Zinc deficiency (44 %) in our outpatient clinic population at King Fahad Hospital. So, there is probably Zinc deficiency in greater numbers in the general population which should be addressed before it becomes an epidemic if there is not one already. 2. Most of the women with Zinc deficiency complained of hair loss. 3. Factors especially phytates that inhibit Zinc absorption should be considered and lower dietary phytates introduced in the foods we eat , especially for children.

Zinc intake and status in Austria in the light of different reference values.

Zinc has been identified as a critical micronutrient also in high-income countries. There is still some uncertainty about the evaluation of zinc sufficiency due to divergent daily intake reference values. We wanted to exemplify this issue using data from the Austrian Study on Nutritional Status 2012. Plasma zinc concentrations were measured in a nationally representative sample of 872 persons aged 6-80 years (55.5 % female). Dietary zinc intake was estimated from two 24h dietary recalls. Additionally, parameters of the antioxidative status (plasma malondialdehyde (MDA), total antioxidative capacity) and activities of alkaline phosphatase (AP), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px)) were determined. Zinc status was marginal in schoolchildren (40 % of boys and 22 % of girls) and in elderly (28 % of men and 33 % of women). Dietary zinc intake was also unsatisfactory in these groups with 38 % of boys and 32 % of girls and 64.5 % of older men below the nationally recommended intake levels. However, the adequacy of zinc intake varied with different reference values. Adults were more likely to meet the D-A-CH reference values and those from the European Food Safety Authority than the recommendations of the International Zinc Nutrition Consultative Group (IZiNCG) and the Institute of Medicine, whereas children met the IZiNCG values best. Zinc status correlated weakly with AP activity (r = -0.298, p < 0.001) and some antioxidant status markers (CAT, MDA, GSH-PX, SOD), especially in the elderly (MDA: r = -0.527, p < 0.001, and SOD: r = -0.466, p = 0.002). Our results suggest a suboptimal zinc supply in Austria particularly among schoolchildren and older adults.

Assessment of Zinc Status in School-Age Children from Rural Areas in China Nutrition and Health Survey 2002 and 2012.

Zinc is an essential trace element for growth and development in children, but zinc deficiency is a serious nutritional problem worldwide. Our study aimed to assess the zinc status of school-age children living in rural areas of China and to examine the change of zinc status based on the China Nutrition and Health Survey 2002 and 2012. We used the probability proportional to size sampling method for subject selection, and a total of 3407 school-age children were included in this study. Zinc status was assessed by three items of indicators recommended by the World Health Organization (WHO), the United Nations Children's Fund (UNICEF), the International Atomic Energy Agency (IAEA), and the International Zinc Nutrition Consultative Group (IZiNCG). The concentration of serum zinc was 718.2μg/L, and 44.4% of children being zinc deficiency in 2002, while 846.8μg/L and 10.4% in 2012. Zinc intake was 7.8mg/day with a 7.6% inadequate zinc intake in 2002, together with 6.9mg/day and 38.2% in 2012. Height-for-age Z score was -1.06 and 19.1% of children being stunting in 2002, as well as -0.15 and 6.8% in 2012. In conclusion, the zinc status of school-age children living in rural areas of China has been significantly improved in addition to zinc intake over the past 10years. However, the zinc deficiency still observed in poor rural areas of China in 2012. In addition, we suggested that the zinc bioavailability should be taken into account when assessing zinc status in population.

A Review of Dietary Zinc Recommendations.

Large discrepancies exist among the dietary zinc recommendations set by expert groups. To describe the basis for the differences in the dietary zinc recommendations set by the World Health Organization, the US Institute of Medicine, the International Zinc Nutrition Consultative Group, and the European Food Safety Agency. We compared the sources of the data, the concepts, and methods used by the 4 expert groups to set the physiological requirements for absorbed zinc, the dietary zinc requirements (termed estimated and/or average requirements), recommended dietary allowances (or recommended nutrient intakes or population reference intakes), and tolerable upper intake levels for selected age, sex, and life-stage groups. All 4 expert groups used the factorial approach to estimate the physiological requirements for zinc. These are based on the estimates of absorbed zinc required to offset all obligatory zinc losses plus any additional requirements for absorbed zinc for growth, pregnancy, or lactation. However, discrepancies exist in the reference body weights used, studies selected, approaches to estimate endogenous fecal zinc (EFZ) losses, the adjustments applied to derive dietary zinc requirements that take into account zinc bioavailability in the habitual diets, number of dietary zinc recommendations set, and the nomenclature used to describe them. Estimates for the physiological and dietary requirements varied across the 4 expert groups. The European Food Safety Agency was the only expert group that set dietary zinc recommendations at 4 different levels of dietary phytate for adults (but not for children) and as of yet no tolerable upper intake level for any life-stage group.

Fractional Zinc Absorption for Men, Women, and Adolescents Is Overestimated in the Current Dietary Reference Intakes

Background: The fractional zinc absorption values used in the current Dietary Reference Intakes (DRIs) for zinc were based on data from published studies. However, the inhibitory effect of phytate was underestimated because of the low phytate content of the diets in the studies used.Objective: The objective of this study was to estimate the fractional absorption of dietary zinc from the US diet by using 2 published algorithms.Methods: Nutrient intake data were obtained from the NHANES 2009–2010 and the corresponding Food Patterns Equivalents Database. Data were analyzed with the use of R software by taking into account the complex survey design. The International Zinc Nutrition Consultative Group (IZiNCG; Brown et al. Food Nutr Bull 2004;25:S99–203) and Miller et al. (Br J Nutr 2013;109:695–700) models were used to estimate zinc absorption.Results: Geometric means (95% CIs) of zinc absorption for all subjects were 30.1% (29.9%, 30.2%) or 31.3% (30.9%, 31.6%) with the use of the IZiNCG model and Miller et al. model, respectively. For men, women, and adolescents, absorption values obtained in this study with the use of the 2 models were 27.2%, 31.4%, and 30.1%, respectively, for the IZiNCG model and 28.0%, 33.0%, and 31.6%, respectively, for the Miller et al. model, compared with the 41%, 48%, and 40%, respectively, used in the current DRIs. For preadolescents, estimated absorption values (31.1% and 32.8% for the IZiNCG model and Miller et al. model, respectively) compare well with the conservative estimate of 30% used in the DRIs. When the new estimates of zinc absorption were applied to the current DRI values for men and women, the results suggest that the Estimated Average Requirement (EAR) and RDA for these groups need to be increased by nearly one-half of the current values in order to meet their requirements for absorbed zinc.Conclusions: These data suggest that zinc absorption is overestimated for men, women, and adolescents in the current DRI. Upward adjustments of the DRI for these groups are recommended.

Rural Beninese Children Are at Risk of Zinc Deficiency According to Stunting Prevalence and Plasma Zinc Concentration but Not Dietary Zinc Intakes

Background: Three commonly recommended indicators for risk assessment of population zinc deficiency are stunting rates among children aged <5 y, prevalence of inadequate dietary zinc intake, and prevalence of low plasma zinc (PZn). Data on zinc status in Benin are mainly drawn from stunting rates and data on PZn and dietary zinc intake are lacking.Objectives: The aims of this study were 1) to assess the risk of zinc deficiency in preschool and school-age children from rural communities in northern Benin by means of the 3 indicators for population assessment, 2) to evaluate their level of agreement, and 3) to identify predictors of PZn and height-for-age z scores (HAZ).Methods: We analyzed preintervention data collected during 2 efficacy trials and cross-sectionally assessed the risk of zinc deficiency in preschool (1–5 y, n = 326) and school-age children (5–10 y, n = 272) by 1) conducting a 3-d weighed food record survey, coupled with direct zinc and phytic acid analysis of consumed foodstuffs, and calculating usual dietary zinc intakes in a subsample of school-age children (n = 36); 2) analyzing PZn in all children (n = 598); and 3) measuring anthropometry indexes for assessment of stunting (HAZ <−2 SD) in all children (n = 594) and in <5-y-old children only (n = 273). We derived predictors of PZn and HAZ by using multivariate regression with mixed-effect models.Results: Prevalence of inadequate intakes of zinc ranged from 11% to 80% depending on whether the estimated average requirements (EARs) by the International Zinc Nutrition Consultative Group or the EARs derived from the WHO's recommended nutrient intakes were used. Prevalence of low PZn adjusted for acute-phase protein status was 45.7%, with higher rates among preschoolers than school-age children (P = 0.002). The stunting rate in <5-y-old children was 51.3%. PZn was predicted by age, methodologic factors, and socioeconomic status, whereas HAZ was predicted by age, sex, hemoglobin, and socioeconomic status.Conclusions: The prevalence of <5-y stunting and the prevalence of low PZn indicate that the risk of zinc deficiency is elevated in this population. Risk estimates based on the prevalence of inadequacy of zinc intakes varied depending on the EARs used, and a consensus would facilitate nutrition survey evaluations. These trials were registered at clinicaltrials.gov as NCT01472211 and NCT01790321.

Effect of increased concentrations of atmospheric carbon dioxide on the global threat of zinc deficiency: a modelling study.

Increasing concentrations of atmospheric carbon dioxide (CO2) lower the content of zinc and other nutrients in important food crops. Zinc deficiency is currently responsible for large burdens of disease globally, and the populations who are at highest risk of zinc deficiency also receive most of their dietary zinc from crops. By modelling dietary intake of bioavailable zinc for the populations of 188 countries under both an ambient CO2 and elevated CO2 scenario, we sought to estimate the effect of anthropogenic CO2 emissions on the global risk of zinc deficiency. We estimated per capita per day bioavailable intake of zinc for the populations of 188 countries at ambient CO2 concentrations (375-384 ppm) using food balance sheet data for 2003-07 from the Food and Agriculture Organization. We then used previously published data from free air CO2 enrichment and open-top chamber experiments to model zinc intake at elevated CO2 concentrations (550 ppm, which is the concentration expected by 2050). Estimates developed by the International Zinc Nutrition Consultative Group were used for country-specific theoretical mean daily per-capita physiological requirements for zinc. Finally, we used these data on zinc bioavailability and population-weighted estimated average zinc requirements to estimate the risk of inadequate zinc intake among the populations of the different nations under the two scenarios (ambient and elevated CO2). The difference between the population at risk at elevated and ambient CO2 concentrations (ie, population at new risk of zinc deficiency) was our measure of impact. The total number of people estimated to be placed at new risk of zinc deficiency by 2050 was 138 million (95% CI 120-156). The people likely to be most affected live in Africa and South Asia, with nearly 48 million (32-63) residing in India alone. Global maps of increased risk show significant heterogeneity. Our results indicate that one heretofore unquantified human health effect associated with anthropogenic CO2 emissions will be a significant increase in the human population at risk of zinc deficiency. Our country-specific findings can be used to help guide interventions aimed at reducing this vulnerability. Bill & Melinda Gates Foundation, Winslow Foundation.

Zinc status of northern Tasmanian adults.

Information regarding Zn status in the Australian population is very limited. Mild deficiencies in Zn have been associated with CVD, impaired immune function and poor healing. A cross-sectional study of 497 northern Tasmanian adults (24-82 years of age) was conducted to assess Zn status. Dietary intakes were assessed by FFQ and serum concentrations of Zn were evaluated using International Zinc Nutrition Consultative Group methodology. Mean Zn intakes were 12·6 (sd 4·4) mg/d for men and 10·9 (sd 3·6) mg/d for women. It was found that 52 % of men but only 9 % of women consumed less than the Australia/New Zealand estimated average requirement for Zn. Mean serum Zn was 13·0 (sd 2·4) µmol/l in men and 13·0 (sd 2·5) µmol/l in women. Overall, 15 % of men and 7 % of women had low serum Zn levels. Furthermore, low serum Zn was observed in 18 % of men 50 years or older and 30 % of men 70 years or older. The present results suggest that mild Zn deficiency may be prevalent in older Tasmanian adults, particularly men; and due to the importance of Zn in many areas of health, this could be of public health concern.

Dietary and non-dietary factors associated with serum zinc in Indian women.

Women in low-income settings, common in India, are at risk of inadequate zinc intake due to poor diet quality and low consumption of flesh foods rich in zinc. The aims of this study were to assess the prevalence of zinc status of non-pregnant rural and tribal women living in central India and to identify dietary and non-dietary factors associated with the biochemical zinc status of these women. Rural and tribal non-pregnant women 18-30 years of age were selected using proportion to population sampling near Nagpur, Maharashtra, India. Sociodemographic, biochemical (serum zinc), clinical, and dietary data (1-day interactive 24-h recall) were collected. The mean age of women (n = 109; rural = 52; tribal = 56) was 23.2 years and mean BMI was 17.9 kg/m(2). The majority of the participants identified as being non-vegetarian (72 %). The mean ± SD serum zinc concentration was 10.8 ± 1.6 μmol/L, and 52 % of participants had a low serum zinc concentration according to the International Zinc Nutrition Consultative Group (IZiNCG). The median (first and third quartile) energy, zinc intake, and phytate/zinc molar ratio was 5.4 (4.2, 6.7) MJ/day, 5.3 (3.8, 7.0) mg/day, and 26 (22, 28), respectively. Zinc intakes were well below IZiNCG recommendations for dietary zinc of 9 mg/day for non-pregnant women aged 14-18 years and 7 mg/day for non-pregnant women aged ≥ 19 years. Using linear regression analysis to identify non-dietary and dietary factors associated with serum zinc, a significant association was only found for current lactation (p = 0.012) and energy intake (p < 0.001). Diets low in energy with poor bioavailability of dietary zinc are likely to be the primary cause of the high proportion of Indian women with zinc deficiency.