Estimating the Global Prevalence of Zinc Deficiency: Results Based on Zinc Availability in National Food Supplies and the Prevalence of Stunting

Large-scale food fortification (LSFF) can increase dietary micronutrient intake and improve micronutrient status. Here we used food balance sheet data from the Food and Agriculture Organization of the United Nations to estimate current country-specific prevalences of inadequate zinc intake. We assessed the potential effects of improving existing LSFF programmes for cereal grains or implementing new programmes in 40 countries where zinc deficiency is a potential public health problem. Accounting for LSFF programmes as currently implemented, 15% of the global population (1.13 billion individuals) is estimated to have inadequate zinc intake. In countries where zinc deficiency is a potential public health problem, the implementation of high-quality mandatory LSFF programmes that include zinc as a fortificant would substantially increase the availability of zinc in the national food supply, reducing the estimated prevalence of inadequate zinc intake by up to 50% globally. Investments in strong LSFF programmes could have a substantial impact on population zinc status.

BackgroundThe prevalence of inadequate zinc intake in a population can be estimated by comparing the zinc content of the food supply with the population’s theoretical requirement for zinc. However, assumptions regarding the nutrient composition of foods, zinc requirements, and zinc absorption may affect prevalence estimates. These analyses were conducted to: (1) evaluate the effect of varying methodological assumptions on country-specific estimates of the prevalence of dietary zinc inadequacy and (2) generate a model considered to provide the best estimates.Methodology and Principal FindingsNational food balance data were obtained from the Food and Agriculture Organization of the United Nations. Zinc and phytate contents of these foods were estimated from three nutrient composition databases. Zinc absorption was predicted using a mathematical model (Miller equation). Theoretical mean daily per capita physiological and dietary requirements for zinc were calculated using recommendations from the Food and Nutrition Board of the Institute of Medicine and the International Zinc Nutrition Consultative Group. The estimated global prevalence of inadequate zinc intake varied between 12–66%, depending on which methodological assumptions were applied. However, country-specific rank order of the estimated prevalence of inadequate intake was conserved across all models (r = 0.57–0.99, P<0.01). A “best-estimate” model, comprised of zinc and phytate data from a composite nutrient database and IZiNCG physiological requirements for absorbed zinc, estimated the global prevalence of inadequate zinc intake to be 17.3%.Conclusions and SignificanceGiven the multiple sources of uncertainty in this method, caution must be taken in the interpretation of the estimated prevalence figures. However, the results of all models indicate that inadequate zinc intake may be fairly common globally. Inferences regarding the relative likelihood of zinc deficiency as a public health problem in different countries can be drawn based on the country-specific rank order of estimated prevalence of inadequate zinc intake.

India has made important strides in reducing nutritional deficiencies over the past several decades. However, for micronutrients such as zinc, previous studies have suggested a worsening situation, contrary to most other dietary indicators. Adding to this burden, higher carbon dioxide (CO2) levels of 550 ppm, projected to potentially occur within decades, could reduce the zinc content of many staple crops. To assess the historical prevalence of inadequate zinc intake, as well as to estimate the future prevalence attributable to rising CO2. Seven household food consumption surveys between 1983 and 2012 were used to calculate total dietary zinc, phytate, and absorbable zinc intakes and to assess the prevalence of historic inadequacy in zinc intake. The added nutritional effect of elevated CO2 on zinc intake is then modeled. Prevalence of inadequate absorbable zinc intake has increased from 17.1% (15.3%-19.0%) in 1983 to 24.6% (22.3%-27.1%) in 2011-12, corresponding to an additional 82 million people consuming inadequate zinc than would have otherwise if 1983 rates had persisted. These increases in inadequacy have been driven by a relatively constant zinc intake being increasingly insufficient to meet a 5% growth in zinc requirements due to the aging of the population. Reaching 550 ppm CO2 by 2050 could potentially increase the prevalence of inadequate zinc intake by another 3.9 percentage points (2.1-5.8), corresponding to 65 million additional people having inadequate zinc intake. The persistently worsening trend for zinc-opposite most other measures of human nutrition-shows that it may pose an ongoing risk unless addressed.

Stunting Prevalence, Plasma Zinc Concentrations, and Dietary Zinc Intakes in a Nationally Representative Sample Suggest a High Risk of Zinc Deficiency among Women and Young Children in Cameroon1–3

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.

BackgroundIn humans, zinc is involved in many biological functions acting as signaling ion, neurotransmitter, structural component of proteins, and cofactor for many enzymes and, through this, is an important regulator of the immune and nervous system. Food supplies zinc to the human body, but a high prevalence of inadequate dietary zinc intake has been reported worldwide.AimsThe objective of this study was to investigate the zinc intake and bioavailability of over 250 women (pregnant and non-pregnant) based in Ireland, in order to evaluate the dietary inadequacy of zinc.MethodologyWe used a food frequency questionnaire designed to assess the zinc intake and bioavailability of the participants.ResultsOur results show that 58% of participants are at risk of inadequate zinc intake and that 29% may be zinc deficient. The prevalence of inadequate zinc intake was lower for pregnant women (zinc deficient 9%, at risk 38%) than for non-pregnant women due to more frequent consumption of supplements. Low zinc intake was not correlated with the age of participants and resulted from a combination of inadequate intake of zinc-rich food and relatively higher intake of food items rich in phytate, a major zinc uptake inhibitor.ConclusionsWe conclude that at present, low zinc intake may be prevalent in as much as 87% of women, including 47% of pregnant women. Therefore, zinc status needs to be considered as a factor impacting the health of women, and in particular pregnant women, also in industrialized and developed countries such as Ireland.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11845-022-03181-w.

The assessment of dietary zinc intakes is an important component of evaluating the risk of zinc deficiency in populations, and for designing appropriate food-based interventions, including fortification, to improve zinc intakes. The prevalence of inadequate zinc intakes can describe the relative magnitude of the risk of zinc deficiency in the population and identify subpopulations at elevated risk. As a cornerstone to evaluating the adequacy of population zinc intakes globally, a set of internationally appropriate dietary reference intakes must be defined. The World Health Organization/Food and Agriculture Organization/International Atomic Energy Agency (WHO/FAO/IAEA) and the Food and Nutrition Board/US Institute of Medicine (FNB/IOM) have presented estimated average requirements (EAR) for dietary zinc intake, and, more recently, the International Zinc Nutrition Consultative Group (IZiNCG) presented a revised set of recommendations for international use. A prevalence of inadequate zinc intakes greater than 25% is considered to represent an elevated risk of population zinc deficiency. As the requirement estimates are derived from smaller, clinical studies and, for children, most components of the estimates are extrapolated from data for adults, it was desirable to evaluate their internal validity. The estimated physiological requirements for adult men and women appear to adequately predict zinc status as determined by biochemical indicators of status and/or zinc balance. With the use of data from available studies, the reported prevalence of low serum zinc concentration and the estimated prevalence of inadequate zinc intakes predict similar levels of risk of zinc deficiency, particularly among pregnant and nonpregnant women. Conformity between these two indicators is less consistent for children, suggesting that further data and/or direct studies of zinc requirements among children are needed.

Background & objectives: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.Methods: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.Results: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.Interpretation & conclusions:Risk of dietary zinc inadequacy and low serum zinc concentration amongst adolescents of the Gond, Bhil and Korku tribes is a public health concern.

Adequate zinc nutriture is critically important for human health, but the development of programmes to control zinc deficiency is limited by the lack of reliable information on population zinc status. The present analyses were conducted to: (1) estimate the absorbable zinc content of national food supplies; (2) compare this information with theoretical population requirements for zinc; and (3) use these results to predict national risks of inadequate zinc intake. National food balance data were obtained for 176 countries from the Food and Agriculture Organization of the United Nations. The amount of absorbable zinc in these foods was estimated from food composition data, and zinc absorption was predicted using a model developed by the International Zinc Nutrition Consultative Group (IZiNCG). Demographic data were obtained from United Nations estimates, and age- and sex-specific physiological requirements for absorbable zinc were estimated using IZiNCG recommendations. The mean per capita absorbable zinc content of national food supplies ranged from 2.98-3.01 mg day(-1) in Western Europe and USA & Canada to 2.09 mg day(-1) in Southeast Asia. The estimated percentage of individuals at risk of inadequate zinc intake ranged from 9.3-9.5% in the regions of North Africa & Eastern Mediterranean and USA & Canada to 33.1% in Southeast Asia. Overall, approximately 20.5% of the world's population is estimated to be at risk of inadequate zinc intake. Data on the absorbable zinc content of national food supplies can be used to determine whether further assessments of population zinc status and development of intervention programmes are warranted.

ObjectivesAdequate zinc nutriture is critically important for human health, but the development of programmes to control zinc deficiency is limited by the lack of reliable information on population zinc status. The present analyses were conducted to: (1) estimate the absorbable zinc content of national food supplies; (2) compare this information with theoretical population requirements for zinc; and (3) use these results to predict national risks of inadequate zinc intake.Setting and design: National food balance data were obtained for 176 countries from the Food and Agriculture Organization of the United Nations. The amount of absorbable zinc in these foods was estimated from food composition data, and zinc absorption was predicted using a model developed by the International Zinc Nutrition Consultative Group (IZiNCG). Demographic data were obtained from United Nations estimates, and age- and sex-specific physiological requirements for absorbable zinc were estimated using IZiNCG recommendations.Results and conclusions: The mean per capita absorbable zinc content of national food supplies ranged from 2.98–3.01 mg day−1 in Western Europe and USA &amp; Canada to 2.09 mg day−1 in Southeast Asia. The estimated percentage of individuals at risk of inadequate zinc intake ranged from 9.3–9.5% in the regions of North Africa &amp; Eastern Mediterranean and USA &amp; Canada to 33.1% in Southeast Asia. Overall, approximately 20.5% of the world's population is estimated to be at risk of inadequate zinc intake. Data on the absorbable zinc content of national food supplies can be used to determine whether further assessments of population zinc status and development of intervention programmes are warranted.

The Current High Prevalence of Dietary Zinc Inadequacy among Children and Women in Rural Bangladesh Could Be Substantially Ameliorated by Zinc Biofortification of Rice1–3

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.

OBJETIVO: Avaliar o estado nutricional relativo ao zinco de crianças assistidas em creches do Estado da Paraíba. MÉTODOS: O estado nutricional relativo ao zinco de 235 crianças pré-escolares foi avaliado através de sua concentração no soro, da ingestão dietética de zinco e da estatura para idade, como recomendado pelo International Zinc Consultative Group. As concentrações séricas de zinco foram determinadas por espectrofotometria de absorção atômica de chama, considerando deficiência de zinco valores &lt;65µmol/L. O consumo alimentar foi registrado mediante o recordatório de 24 horas, considerando a alimentação da criança no dia anterior e o consumo de alimentos na creche, e foi analisada a inadequação dietética de zinco de acordo com as necessidades médias estimadas de zinco segundo etapa da vida e tipo de dieta estabelecido pelo International Zinc Consultative Group. Adotou-se o Padrão de Crescimento Infantil da Organização Mundial da Saúde para o índice estatura para idade, considerando-se com deficit de estatura as crianças que apresentaram esse índice dois escores-Z abaixo do valor mediano da população de referência. Empregou-se o teste t ou análise de variância na análise estatística, programa Statistical Package for the Social Sciences-16.0. RESULTADOS: As prevalências de deficiência de zinco no soro, inadequação dietética de zinco e deficit de estatura foram de 16,2%, 16,6% e 7,7%, respectivamente. A média de zinco no soro foi estatisticamente menor nas crianças de mães com baixo peso em comparação com as crianças de mães com peso normal. CONCLUSÃO: As crianças estudadas apresentaram risco moderado de deficiência de zinco, pois são indicadas prevalências significativas de baixos níveis séricos de zinco, de consumo inadequado de zinco e de desnutrição crônica.

Zinc deficiency is an important cause of morbidity in developing countries, particularly among young children, yet little information is available on the global prevalence of zinc deficiency. A working group meeting was convened 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) to review methods of assessing population zinc status and provide standard recommendations for the use of specific biochemical, dietary, and functional indicators of zinc status in populations. The recommended biochemical indicator is the prevalence of serum zinc concentration less than the age/sex/time of day-specific cutoffs; when the prevalence is greater than 20%, intervention to improve zinc status is recommended. For dietary indicators, the prevalence (or probability) of zinc intakes below the appropriate estimated average requirement (EAR) should be used, as determined from quantitative dietary intake assessments. Where the prevalence of inadequate intakes of zinc is greater than 25%, the risk of zinc deficiency is considered to be elevated. Previous studies indicate that stunted children respond to zinc supplementation with increased growth. When the prevalence of low height-for-age is 20% or more, the prevalence of zinc deficiency may also be elevated. Ideally, all three types of indicators would be used together to obtain the best estimate of the risk of zinc deficiency in a population and to identify specific subgroups with elevated risk. These recommended indicators should be applied for national assessment of zinc status and to indicate the need for zinc interventions. The prevalence of low serum zinc and inadequate zinc intakes may be used to evaluate their impact on the target population's zinc status.

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.