Associations between dietary iron and zinc intakes, and between biochemical iron and zinc status in women

Dietary Zn deficiency, the current situation and potential solutions

Zinc (Zn) deficiency is a worldwide problem, and this review presents an overview of the magnitude of Zn deficiency with a particular emphasis on present global challenges, current recommendations for Zn intake, and factors that affect dietary requirements. The challenges of monitoring Zn status are clarified together with the discussion of relevant Zn bioaccessibility and bioavailability issues. Modern lifestyle factors that may exacerbate Zn deficiency and new strategies of reducing its effects are presented. Biofortification, as a potentially useful strategy for improving Zn status in sensitive populations, is discussed. The review proposes potential actions that could deliver promising results both in terms of monitoring dietary and physiological Zn status as well as in alleviating dietary Zn deficiency in affected populations.

R. S, Bhat MA, Kar S, Mahanta BN, Mathew JL, Nair S, Singh CM, Singh K, Thekkumkara Surendran A. Association of dietary intake with micronutrient deficiency in Indian school children: a cross-sectional study

Adequate nutrition is necessary during childhood and early adolescence for adequate growth and development. Hence, the objective of the study was to assess the association between dietary intake and blood levels of minerals (calcium, iron, zinc, and selenium) and vitamins (folate, vitamin B12, vitamin A, and vitamin D) in urban school going children aged 6-16 years in India, in a multicentric cross-sectional study. Participants were enrolled from randomly selected schools in ten cities. Three-day food intake data was collected using a 24-h dietary recall method. The intake was dichotomised into adequate and inadequate. Blood samples were collected to assess levels of micronutrients. From April 2019 to February 2020, 2428 participants (50⋅2 % females) were recruited from 60 schools. Inadequate intake for calcium was in 93⋅4 % (246⋅5 ± 149⋅4 mg), iron 86⋅5 % (7⋅6 ± 3⋅0 mg), zinc 84⋅0 % (3⋅9 ± 2⋅4 mg), selenium 30⋅2 % (11⋅3 ± 9⋅7 mcg), folate 73⋅8 % (93⋅6 ± 55⋅4 mcg), vitamin B12 94⋅4 % (0⋅2 ± 0⋅4 mcg), vitamin A 96⋅0 % (101⋅7 ± 94⋅1 mcg), and vitamin D 100⋅0 % (0⋅4 ± 0⋅6 mcg). Controlling for sex and socioeconomic status, the odds of biochemical deficiency with inadequate intake for iron [AOR = 1⋅37 (95 % CI 1⋅07-1⋅76)], zinc [AOR = 5⋅14 (95 % CI 2⋅24-11⋅78)], selenium [AOR = 3⋅63 (95 % CI 2⋅70-4⋅89)], folate [AOR = 1⋅59 (95 % CI 1⋅25-2⋅03)], and vitamin B12 [AOR = 1⋅62 (95 %CI 1⋅07-2⋅45)]. Since there is a significant association between the inadequate intake and biochemical deficiencies of iron, zinc, selenium, folate, and vitamin B12, regular surveillance for adequacy of micronutrient intake must be undertaken to identify children at risk of deficiency, for timely intervention.

Nutrient intakes of pregnant and lactating women in Indonesia and Malaysia: Systematic review and meta-analysis

Introduction

Optimizing dietary intake during pregnancy and lactation is crucial to the growth and development of children and their lifelong health. We performed a systematic review and meta-analysis to describe the nutrient intakes of pregnant and lactating women in Indonesia and Malaysia, countries that are experiencing rapid nutrition transition in Southeast Asia.

Methods

We screened 2,258 studies published between January 1980 and March 2021. The nutrient intakes of pregnant and lactating women were quantitatively analyzed to calculate the percentage of adequacy using national recommended daily allowances or nutrient intakes (RDA/RNI) and estimated average requirements (EAR) for micronutrients. Standardized mean differences (SMD) between dietary intake and RDA/RNI were determined for selected nutrients.

Results

Fifty-three studies were included and showed that energy and macronutrient intakes among pregnant and lactating women in both countries were below the RDA/RNI. In addition, most studies reported that women failed to meet the EAR for vitamin D (<70% EAR), vitamin E (<50% EAR), and water-soluble vitamins (<80% EAR) except for vitamin C and A among Malaysians. Moreover, calcium, potassium, and iron intakes of pregnant women were <60% EAR in Indonesia and <80% EAR in Malaysia. Phosphorus intake among pregnant women in both countries and sodium intake among Malaysian pregnant women exceeded 100% EAR. Indonesian lactating women had <60% EAR for calcium and potassium intakes, while Malaysian women had more than 100% EAR. For 21 studies reporting overall protein intakes, the standard mean difference (SMD) was −2.26 (95% CI; −2.98, −1.54) below the RDA/RNI for pregnant women and −0.67 SMD (95% CI −15.7, −11.5) for lactating women. When the four studies from Malaysia were analyzed separately, protein intakes of pregnant women were above the RNI. Moreover, low intakes of vitamin D, vitamin C, calcium, and iron, but sufficient intakes in vitamin A, zinc, and phosphorus were observed in pregnant women in both countries.

Conclusion

Dietary intakes of energy, macronutrients, and micronutrients (vitamin D, vitamin E, water-soluble vitamins, calcium, and iron) of pregnant and lactating women in Indonesia and Malaysia were below the recommendations. Important heterogeneities were observed even between these two countries for specific essential nutrient intakes. Innovative research and targeted programs to address specific deficiencies should be prioritized.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021252204, identifier: CRD42021252204.

Prevalence of specific micronutrient deficiencies in urban school going children of India aged between 6 and 16 years: study protocol for a multicentric cross-sectional study

INTRODUCTION

Childhood and adolescence are the period of rapid physical and cognitive growth and development, requiring adequate nutrition. Malnutrition in the form of undernutrition or micronutrient deficiency or overweight/obesity affects the health, cognition and educational achievement of this age group. The objective of this study is to assess the prevalence of calcium, iron, zinc, selenium, folate, vitamin A, 25 hydroxy vitamin D and vitamin B12 deficiencies in the serum and haemoglobin, ferritin and lead levels and its association with reported dietary intake and cognitive abilities, in urban school going children aged 6-16 years in 10 cities of India.

METHODS AND ANALYSIS

A multicentric cross-sectional study will be conducted to recruit 2400 participants (240 per site) across India. Participants will be selected using random sampling and will be categorised into age groups of 6-11 years and 12-16 years, with equal distribution. Data on socioeconomic status, anthropometric measures and 3-day dietary intake and cognitive performance will be collected. Blood samples will be collected for biochemical analysis of micronutrients. Findings will estimate the prevalence of micronutrient deficiencies and their association with dietary habits and cognitive functioning.

ETHICS AND DISSEMINATION

Study protocol has been reviewed and approved by institutional ethics committee of all 10 participating sites. Results will be shared and published in a peer-reviewed journal, so that the findings will be helpful for the stakeholders in planning nutritional interventions for targeted groups.

TRIAL REGISTRATION NUMBER

CTRI/2019/02/017783.

Effectiveness of eight-week zinc supplementation on vitamin D3 status and leptin levels in a population of postmenopausal women: a double-blind randomized trial

BACKGROUND

The menopausal period is characterized by hormonal imbalance related to the alteration of parameters involved in lipid metabolism. In addition, menopause increases the risk of deficiencies of key vitamins and minerals such as vitamin D and zinc in such women. The present study investigates the influence of zinc supplementation on the status of vitamin D₃ and other lipid parameters in postmenopausal women.

METHODS

Fifty-one healthy postmenopausal women aged 44-76 years from the province of Granada (Spain) were divided into two groups (placebo and zinc) of 25 and 26 women, respectively. The zinc group was supplemented with 50 mg/day of zinc for 8 weeks. Nutrient intake assessment was performed by means of a 24 -h reminder. Zinc was determined by flame atomic absorption spectrophotometry. Vitamin D was analyzed by liquid chromatography - tandem mass spectrometry. Leptin was determined by enzyme immunoassay.

RESULTS

Zinc supplementation improved the initial vitamin D₃ status of the postmenopausal population (p = 0.049). Plasma levels of 25-OH-D₃ increased significantly after Zn supplementation in women with lower age at menopause (p = 0.045). Both intake and plasma zinc levels were inversely correlated to serum leptin levels (p = 0.044 and p = 0.033, respectively), being significantly lower in lower age at menopause (p < 0.001).

CONCLUSION

Zinc supplementation improved vitamin D₃ status and was associated to low leptin levels in the postmenopausal women of the study.

Molar ratios of dietary phytate to minerals and iron status of female residential students in University of Dhaka, Bangladesh

BACKGROUND

Female undergraduate students may undergo many health implications due to the transition from secondary to undergraduate level.

AIM

The study was aimed to assess molar ratios of phytate to minerals (calcium, zinc, and iron) in the diets, and to measure the iron status of resident female students at Dhaka University.

METHODS

In total, 180 female students between 18-26 years of age from 3 dormitories of Dhaka University were selected for the study. Dietary intake information was collected over three consecutive days. Multiple-Pass 24-hour recall. Blood hemoglobin and serum ferritin levels were analyzed for sub-sample (20 participants from each dormitory).

RESULTS

The mean dietary intake of phytate, calcium, zinc, and iron were estimated at 347.11, 181.04, 6.59, and 7.14 mg/day, and hemoglobin and serum ferritin at 11.34 g/dl, and 18.48 ng/ml, respectively. The respective molar ratios of phytate: calcium, phytate: zinc, phytate: iron and phytate × calcium: zinc were 0.13, 5.27, 4.20, and 21.26 in the diet of the respondents. The prevalence of anemia, iron deficiency and iron deficiency anemia among the respondents was found to be 51.7%, 48.4%, and 28.3%, respectively. Linear regression analysis showed that only zinc intake had positive association with hemoglobin, while iron and zinc intake had a significant positive, and phytate:iron molar ratio had a significant negative association with serum ferritin concentration (p < 0.05). After adjusting all significant determinants of serum ferritin, no predictors have found significant.

CONCLUSIONS

Larger and more specific research is needed to clearly understand the mechanism behind anemia and iron deficiency among female residential students.

The Gut‒Breast Axis: Programming Health for Life

The gut is a pivotal organ in health and disease. The events that take place in the gut during early life contribute to the programming, shaping and tuning of distant organs, having lifelong consequences. In this context, the maternal gut plays a quintessence in programming the mammary gland to face the nutritional, microbiological, immunological, and neuroendocrine requirements of the growing infant. Subsequently, human colostrum and milk provides the infant with an impressive array of nutrients and bioactive components, including microbes, immune cells, and stem cells. Therefore, the axis linking the maternal gut, the breast, and the infant gut seems crucial for a correct infant growth and development. The aim of this article is not to perform a systematic review of the human milk components but to provide an insight of their extremely complex interactions, which render human milk a unique functional food and explain why this biological fluid still truly remains as a scientific enigma.

Diet, Exercise, Lifestyle, and Mental Distress among Young and Mature Men and Women: A Repeated Cross-Sectional Study

Customization of mental health therapies needs to consider the differences in degree of brain maturity between young (18–29 years) and mature (30 years or older) adults as well as brain morphology among men and women. The aim of this study was to identify the significant dietary and lifestyle contributors to mental distress in these sub-populations. Independent repeated cross-sectional sampling was performed for over a 5-year period (2014–2019) to collect data from different populations at different time-points and seasons. A backward stepwise regression analysis was used on 2628 records. Mental distress in young women was associated with high consumption of caffeine and fast-food, and it was negatively correlated with moderate-high levels of exercise as well as frequent breakfast consumption. Mature women shared several common factors with young women; however, high fruit consumption was negatively associated with mental distress. For young men, high exercise, moderate consumption of dairy, and moderate-high intake of meat were negatively associated with mental distress. In addition, high fast-food and caffeine consumption were positively associated with mental distress in young men. For mature men, strong negative associations between higher education, moderate intake of nuts and mental distress surfaced. Our results support the need to customize dietary and lifestyle recommendations to improve mental wellbeing.

Inflammation Adjustment by Two Methods Decreases the Estimated Prevalence of Zinc Deficiency in Malawi

Serum zinc concentration (SZC) is used widely to assess population-level zinc status. Its concentration decreases during inflammatory responses, which can affect the interpretation of the results. This study aimed to re-estimate the prevalence of zinc deficiency in Malawi based on the 2015-2016 Malawi Micronutrient Survey (MNS) data, by adjusting SZC measures with markers of inflammation. SZC and inflammation data from 2760 participants were analysed. Adjustments were made using: (1) The Internal Correction Factor (ICF) method which used geometric means, and (2) The Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) method, which used linear regression. Mean SZC values increased significantly when adjustments were made by either ICF or BRINDA (p < 0.001). The national prevalence of zinc deficiency decreased from 62% to 59%, after ICF adjustment, and to 52% after BRINDA adjustment. ICF and BRINDA values of SZC were highly correlated (p < 0.001, r = 0.99), but a Bland-Altman plot showed a lack of agreement between the two methods (bias of 2.07 µg/dL). There was no association between the adjusted SZC and stunting, which is a proxy indicator for zinc deficiency. Inflammation adjustment of SZC, using ICF or BRINDA, produces lower estimates of zinc deficiency prevalence, but the lack of agreement between the adjustment methods warrants further research. Furthermore, the lack of association between SZC and stunting highlights the need to explore other biomarkers and proxies of population zinc assessment. This study demonstrates the importance of considering inflammatory confounders when reporting SZC, to ensure accuracy and to support policy decision making.

Urinary Metal Levels with Relation to Age, Occupation, and Smoking Habits of Male Inhabitants of Eastern Iran

In low-income and middle-income countries such as Iran, smoking is becoming increasingly popular, especially among young people. This has led to additional exposure to a variety of substances, including metals which may exert a toxic influence and lead to severe diseases. In order to evaluate the influence of smoking on metal concentrations, a case-control study of levels of metal in urine was carried out in smokers (n = 64) and non-smokers (n = 35) from the city of Birjand (Iran). They were divided according to their age and socioeconomic status. Concentrations of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn) were measured using ET-AAS. We found higher concentrations of Cd (0.03 vs. 0.12 μg/L), Co (0.6 vs. 1.22 μg/L), and Cr (14.00 vs. 18.17 μg/L) in the urine of smokers. Age and occupation are factors that also influence the levels of metals. Young smokers demonstrate higher Cd and Pb levels than other age groups. It would also appear that public sector workers and self-employed are the sectors most susceptible to high levels of metals.

The Associations of Dietary Iron, Zinc and Magnesium with Metabolic Syndrome in China's Mega Cities

Background: Iron, zinc and magnesium perform differently in body metabolism but exist in similar food. This study was to evaluate the associations of dietary iron, zinc and magnesium with metabolic syndrome (MetS). Methods: A sample of a total of 5323 participants from four of China’s mega cities was included in the current study. Both a 3-day 24-h dietary recall and household condiment weighing were applied to assess dietary intake, respectively. Hierarchical logistic regression models were used to evaluate the associations of dietary iron, zinc and magnesium with MetS. Results: After adjusting for age, sex, region, years of education, physical activity level, intended physical exercises, smoking status, alcohol use, daily energy intake and mutual adjustment for dietary iron, zinc and magnesium, significant positive trends were found across quartiles of total dietary iron and the risk of MetS, as well as for magnesium and MetS (p value for trends = 0.01 and 0.02, respectively); dietary zinc was inversely associated with MetS risk (p value for trend < 0.01). Magnesium from grains and potato was positively associated with MetS (p value for trend < 0.01). Conclusions: Dietary iron and magnesium were positively associated with the risk of MetS, while zinc was inversely associated with the risk of MetS, in China’s mega cities. The positive association of magnesium with MetS could be a result confounding by other factors correlated with magnesium in grains and potato, which warrants further study.

Urban and rural area differences in the interaction between oxidative process elements in human femoral bone

Elements in the human body come from contaminated food, water, and air from the living area. Bones are a marker of long-term exposure to elements and show a relationship between them. The aim of the study was to analyze the correlation between the contents of Zn, Cu, Fe, Mo, Cr, Ni, Ba, Sr, and Pb in the proximal femoral head (cancellous bone) and femoral neck (cortical bone) in rural and urban populations. The study included 96 patients who were operated on for total hip replacement (THR), acquired in a surgical procedure with atomic absorption spectrometry, and the content of Zn, Cu, Fe, Mo, Cr, Ni, Ba, Sr, and Pb was evaluated. In rural areas, significant negative correlations were observed for Mo/Cr, Mo/Cu, and Ni/Fe, and positive correlations were observed for Fe/Zn and Pb/Zn. In urban areas, a negative correlation was found for Pb/Mo. Pb and Ni increased with age only in villagers, and Zn and Sr decreased with age in urban citizens. Ba decreased with age in people from rural areas. The correlation showed variances mainly in molybdenum, nickel, and oxidative elements between rural and urban populations.

Association between Haem and Non-Haem Iron Intake and Serum Ferritin in Healthy Young Women

Iron is an essential micronutrient for human health and inadequate intake may result in iron deficiency (ID) or iron deficiency anaemia (IDA). Unlike other recent studies investigating iron status in young women, this cross-sectional study analysed dietary intake and biochemical data from healthy young (18-35 years) women (n = 299) to determine the association between both haem iron (HI) and non-haem iron (NHI) intakes and serum ferritin (SF). Dietary restraint and possible inflammation secondary to obesity were also measured and accounted for, and energy intake was adjusted for using the residuals method. Independent samples t-tests and chi-squared tests were performed, and factors found to be significantly different between iron replete (IR) and ID/IDA participants were analysed using general linear modelling. ID/IDA participants consumed significantly lower total energy than iron replete (IR) (p = 0.003). Lower energy intake was also associated with higher levels of dietary restraint (p = 0.001). Both HI and NHI were positively associated with SF with HI was found to be a stronger predictor (β = 0.128, p = 0.009) than NHI (β = 0.037, p = 0.028). The study demonstrates that intake of both HI and NHI, as well as adequate dietary energy, are associated with normal iron status levels in young women, and that restrained eaters may be at greater risk of low iron status.

Association mapping unveils favorable alleles for grain iron and zinc concentrations in lentil (Lens culinaris subsp. culinaris)

Lentil is a major cool-season grain legume grown in South Asia, West Asia, and North Africa. Populations in developing countries of these regions have micronutrient deficiencies; therefore, breeding programs should focus more on improving the micronutrient content of food. In the present study, a set of 96 diverse germplasm lines were evaluated at three different locations in India to examine the variation in iron (Fe) and zinc (Zn) concentration and identify simple sequence repeat (SSR) markers that associate with the genetic variation. The genetic variation among genotypes of the association mapping (AM) panel was characterized using a genetic distance-based and a general model-based clustering method. The model-based analysis identified six subpopulations, which satisfactorily explained the genetic structure of the AM panel. AM analysis identified three SSRs (PBALC 13, PBALC 206, and GLLC 563) associated with grain Fe concentration explaining 9% to 11% of phenotypic variation and four SSRs (PBALC 353, SSR 317-1, PLC 62, and PBALC 217) were associated with grain Zn concentration explaining 14%, to 21% of phenotypic variation. These identified SSRs exhibited consistent performance across locations. These candidate SSRs can be used in marker-assisted genetic improvement for developing Fe and Zn fortified lentil varieties. Favorable alleles and promising genotypes identified in this study can be utilized for lentil biofortification.

The influence of food consumption and socio-economic factors on the relationship between zinc and iron intake and status in a healthy population

OBJECTIVE

To examine Zn and Fe nutritional status of a healthy population by means of anthropometric, dietary and biochemical measurements and to investigate the relationship of usual Zn and Fe dietary intakes to Zn and Fe status. In addition, to examine the impact of food choices and socio-economic factors on Fe and Zn dietary intakes and status with the aim to identify groups at risk of dietary deficiency and suggest factors that may influence the status of these nutrients.

DESIGN

Food consumption was assessed by 24 h recall questionnaires. Twenty biochemical parameters were measured, of which Hb, haematocrit, erythrocyte count and plasma concentrations of Fe and Zn were directly related to Fe and Zn nutrition. The prevalence of study participants with inadequate micronutrient intakes was calculated using the Estimated Average Requirement cut-point method.

SETTING

Serbia, Europe.

SUBJECTS

Apparently healthy adults (25-65 years of age).

RESULTS

Mean daily Zn and Fe intakes were 9·1 mg and 11·6 mg for males and 7·3 mg and 9·4 mg for females, respectively. Five per cent of the study population had inadequate dietary Fe intake and 15-25 % had inadequate Zn intake. Lower Hb concentrations were measured in women with lower Zn intakes. No differences in Fe and Zn intakes and status among various socio-economic groups were observed, except for Fe intake between the low-income and affluent groups.

CONCLUSIONS

Regular follow-ups are needed to ensure that potential deficiencies of Zn and Fe do get recognized and addressed in a timely manner.

Hepcidin is a Better Predictor of Iron Stores in Premenopausal Women than Blood Loss or Dietary Intake

The relationship between dietary intake, circulating hepcidin and iron status in free-living premenopausal women has not been explored. This cross-sectional study aimed to identify dietary determinants of iron stores after accounting for blood loss and to determine whether iron intake predicts iron stores independently of hepcidin in a sample of Australian women. Three hundred thirty eight women aged 18-50 years were recruited. Total intake and food sources of iron were determined via food frequency questionnaire; the magnitude of menstrual losses was estimated by self-report; and blood donation volume was quantified using blood donation records and self-reported donation frequency. Serum samples were analysed for ferritin, hepcidin and C-reactive protein concentrations. Linear regression was used to investigate associations. Accounting for blood loss, each 1 mg/day increase in dietary iron was associated with a 3% increase in iron stores (p = 0.027); this association was not independent of hepcidin. Hepcidin was a more influential determinant of iron stores than blood loss and dietary factors combined (R² of model including hepcidin = 0.65; R² of model excluding hepcidin = 0.17, p for difference <0.001), and increased hepcidin diminished the positive association between iron intake and iron stores. Despite not being the biggest contributor to dietary iron intake, unprocessed meat was positively associated with iron stores, and each 10% increase in consumption was associated with a 1% increase in iron stores (p = 0.006). No other dietary factors were associated with iron stores. Interventions that reduce hepcidin production combined with dietary strategies to increase iron intake may be important means of improving iron status in women with depleted iron stores.