Sun exposure as a strategy for acquiring vitamin D in developing countries of tropical region: Challenges & way forward.

Adopting sun exposure as a low-cost sustainable strategy in tropical countries needs critical analysis for its feasibility and inclusion in national policy. This review explores the opportunities and challenges associated with sun exposure in tropical countries and discusses potential strategies that may be adopted for promoting sun exposure. For this, two strands of evidence were reviewed; trials on sun exposure, analysed for risk of bias and, the environmental factors that influence acquisition of vitamin D from sun exposure in the context of on-going ecological and nutritional transition. Compilation of data from available databases in terms of deficiency, per cent rural population, status of fortification, air pollution, ultraviolet index, skin reflectance and skin cancer prevalence were done. In the context of environmental and lifestyle-related challenges, opportunities go hand-in-hand in terms of built environment, variability in air pollution and personal factors such as skin pigmentation, precursor availability and general nutritional status. Contextual policy decisions should consider urban and rural development planning, control of air pollution, targeted guidelines for indigenous and immigrant population and use of space technology in educating general population for balanced sun exposure as essential components for a sustainable strategy. Important opportunities exist for tropical countries to develop sun exposure as a strategy for acquiring vitamin D and these need to be explored.

Impact of iron-fortified foods on Hb concentration in children (<10 years): a systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: To combine evidence from randomized controlled trials to assess the effect of Fe-fortified foods on mean Hb concentration in children (<10 years). DESIGN: We conducted a meta-analysis of randomized, controlled, Fe-fortified feeding trials that evaluated Hb concentration. The weighted mean difference was calculated for net changes in Hb by using random-effects models. Meta-regression and covariate analyses were performed to explore the influence of confounders on the net pooled effect. SETTING: Trials were identified through a systematic search of PubMed, the Cochrane Library and secondary references. SUBJECTS: Eighteen studies covering 5142 participants were identified. The duration of feeding of fortified foods ranged from 6 to 12 months in these studies. RESULTS: Eighteen studies were included and evaluated in the meta-analysis. The overall pooled estimate of Hb concentration showed a significant increase in the fortification group compared with the control group (weighted mean difference = 5·09 g/l; 95% CI 3·23, 6·95 g/l; I 2 = 90%, τ 2 = 18·37, P < 0·0001). Meta-regression analysis indicated that duration of feeding was positively related to the effect size (regression coefficient = 0·368; 95% CI 0·005, 0·731; P < 0·05). The net pooled effect size after removing the confounders was 4·74 (95% CI 3·08, 6·40) g/l. CONCLUSIONS: We observed an association between intake of Fe-fortified foods and Hb concentration in children aged <10 years. Fe-fortified foods could be an effective strategy for reducing Fe-deficiency anaemia in children.

Prevalence and Correlates of Vitamin D Deficiency Among Children and Adolescents From a Nationally Representative Survey in India.

OBJECTIVE: To evaluate the prevalence of vitamin D deficiency (VDD) and its correlates among apparently healthy children and adolescents. METHODS: We carried out a secondary analysis of data of Comprehensive National Nutrition Survey 2016-18 to analyze the pre-valence and predictors of VDD among Indian children and adolescents. RESULTS: The over-all prevalence of VDD in preschool children (1-4 years), school age (5-9 years) children, and adolescents (10-19 years) was 13.7%, 18.2%, and 23.9%, respectively. Age, living in urban area, and winter season were significantly associated with VDD. Vegetarian diet and high-income households were the main risk factors observed in 5-19 years age category. Female sex and less than three hour of physical activity/week were independent risk factors among adolescents. CONCLUSION: The prevalence and determinants of VDD across different age-groups are reported, and these should be interpreted and addressed to decrease the burden of VDD in India.

Psychometric validation of a knowledge questionnaire on micronutrients among adolescents and its relationship to micronutrient status of 15-19-year-old adolescent boys, Hyderabad, India.

OBJECTIVE: To develop a psychometrically valid questionnaire for testing knowledge on micronutrients and to assess the relationship between knowledge and biomarkers of micronutrient status among adolescents. DESIGN: Cross-sectional, institution-based, validity and reliability study. SETTING: Seven higher secondary schools were covered in the limits of Greater Hyderabad Municipal Corporation, Hyderabad, India. SUBJECTS: Students aged 15-19 years, n 92 for the pre-test, n 108 for test-retest and n 109 for studying the relationship between knowledge and biomarkers of Fe, retinol, ascorbic acid, α-tocopherol, folic acid and vitamin B12 status. RESULTS: From an item pool of 106, thirty-one items were selected based on content validity. Statistical tools to obtain a valid and reliable questionnaire among adolescent boys and girls resulted in eighteen items with a difficulty index of 0·11-0·86, discrimination index of 0·20-0·72 and validity index (point bi-serial correlation) of 0·10-0·62. Reliability as measured by Cronbach's α was 0·71 and the intra-class correlation coefficient was 0·80. A Bland-Altman plot showed good agreement between test and retest scores. The mean response score to the eighteen-item questionnaire was 5·2 (sd 2·68). The mean values of serum retinol were significantly different (P = 0·022) between groups below (24·8 (sd 6·64) µg/dl) and above (28·0 (sd 7·67) µg/dl) the 50th percentile of knowledge score. The relationship persisted after controlling for economic status as a covariate using analysis of covariance (P = 0·018). Other micronutrients did not show any significant relationship. CONCLUSIONS: A valid and reliable eighteen-item knowledge questionnaire was constructed and found to have a significant positive relationship with plasma retinol status alone.

Perceived stress, life events & coping among higher secondary students of Hyderabad, India: a pilot study.

BACKGROUND & OBJECTIVES: Psychosocial stressors leading to allostatic load need to be explored further as these have great scope for early intervention. Stress studies done in India are mostly based on sources of stress and objective measures of stress. Therefore, the objective of the present study was to assess stress appraisal among students (16-17 yr) and to identify institution-specific differences (Private vs. Government) in stress appraisal and coping. METHODS: The study was carried out among 16-17 yr old apparently normal students. Eighty students were recruited from six schools ensuring equal representation from gender/category of schools (Government/Private). Validated and culturally adaptable behavioural scales for perceived stress (PSS), stressful life events (LES) and coping were administered. Psychological morbidity was assessed using GHQ-12. Data on 75 students were available for statistical analysis. RESULTS: The students of both Government and Private schools showed similar stress perception, though the former tend to have a higher mean score. The scores were significantly higher on avoidance coping (P<0.05). The stepwise regression model showed coping as the independent predictor of perceived stress (R2 = 10%). INTERPRETATION & CONCLUSIONS: Students from Government schools had significantly higher scores on avoidance coping and therefore, suitable for a systematic study on chronic stress for early intervention.

Prevalence of vitamin A deficiency and its determinants among the rural pre-school children of Madhya Pradesh, India.

BACKGROUND: Vitamin A deficiency (VAD) continues to be a major public health nutritional problem in India, even though the National Vitamin A Prophylaxis Programme has been in operation for more than three decades. AIM: To assess the prevalence of vitamin A deficiency among rural pre-school children. SUBJECTS AND METHODS: A community-based cross-sectional study was carried out in rural Madhya Pradesh. A total of 8777 pre-school children were clinically examined for VAD and blood vitamin A levels were estimated in a sub-sample by dried blood spot method. RESULTS: Prevalence of night blindness and Bitot's spot, an objective sign of VAD, was 0.8% and 1.4%, respectively, and prevalence increased significantly (p < 0.001) with age. The proportion of children with blood vitamin A deficiency ( < 20 µg/dL) was 88% (95% CI: 84.8-91.2).The prevalence of Bitot's spot was significantly (p < 0.001) higher among children of lower socio-economic communities, 3-5-year age group and those of illiterate mothers. CONCLUSIONS: VAD is a major public health problem among rural children of Madhya Pradesh. Children of 3-5 years and those belonging to lower socio-economic communities are at high risk of VAD. Therefore, appropriate intervention measures are to be initiated to improve the vitamin A status of children.

Characterisation of the types of anaemia prevalent among children and adolescents aged 1-19 years in India: a population-based study.

BACKGROUND: Anaemia is a serious public health concern in India. However, national estimates for its prevalence are not available for the 5-14 years age group, nor are estimates available for the types of anaemia among children and adolescents (1-19 years). We aimed to assess the prevalence of anaemia among children and adolescents in India and to categorise types of anaemia on the basis of micronutrient deficiencies. METHODS: We assessed the prevalence of anaemia among children (1-4 years and 5-9 years) and adolescents (10-19 years) using nationally representative data from the Comprehensive National Nutrition Survey. Anaemia was classified on the basis of age and sex-specific WHO cutoffs and serum ferritin, soluble transferrin receptor, folate, cyanocobalamin, and C-reactive protein concentrations as iron deficiency anaemia, folate or vitamin B12 deficiency anaemia, dimorphic anaemia (iron deficiency anaemia and folate or vitamin B12 deficiency anaemia), anaemia of other causes (anaemia not classified as iron deficiency anaemia and folate or vitamin B12 deficiency anaemia), and anaemia of inflammation. FINDINGS: We included 26 765 children (11 624 aged 1-4 years and 15 141 aged 5-9 years) and 14 669 adolescents. In the weighted sample, anaemia prevalence was 40·5% (4553 of 11 233) among 1-4 year-olds, 23·4% (3439 of 14 664) among 5-9 year-olds, and 28·4% (4064 of 14 300) among adolescents. Among 2862 children aged 1-4 years, iron deficiency anaemia (1045 [36·5%]) was the most prevalent type, followed by anaemia of other causes (702 [24·5%]), folate or vitamin B12 deficiency anaemia (542 [18·9%]), dimorphic anaemia (387 [13·5%]), and anaemia of inflammation (186 [6·5%]). Among 2261 children aged 5-9 years, anaemia of other causes was the most common (986 [43·6%]), followed by folate or vitamin B12 deficiency anaemia (558 [24·6%]), iron deficiency anaemia (353 [15·6%]), dimorphic anaemia (242 [10·7%]), and anaemia of inflammation (122 [5·4%]). 861 (31·4%) of 2740 adolescents had anaemia of other causes, 703 (25·6%) had folate or vitamin B12 deficiency anaemia, 584 (21·3%) had iron deficiency anaemia, 498 (18·2%) and dimorphic anaemia, and 94 (3·4%) had anaemia of inflammation. INTERPRETATION: Iron deficiency anaemia is the most common form of anaemia among younger children and anaemia of other causes among 5-9-year-old children and adolescents. Folate or vitamin B12 deficiency anaemia accounts for more than a third of anaemia prevalence. Anaemia prevention efforts should focus on strengthening the existing iron and folate supplementation programmes and prevention of folate or vitamin B12 deficiency anaemia. FUNDING: The Mittal Foundation.

Iron content, bioavailability & factors affecting iron status of Indians.

Repeated surveys have shown that the magnitude of nutritional anaemia is of public health concern in India. Though reduced intake of iron is a major aetiological factor, low intake or an imbalance in the consumption of other haematopoietic nutrients, their utilization; increased nutrient loss and/or demand also contribute to nutritional anaemia. In India, cereals and millets form the bulk of the dietaries and are major sources of non-haeme iron. According to the current estimates, the intake of iron is less than 50 per cent of the recommended dietary allowance (RDA) and iron density is about 8.5 mg/1000 Kcal. It is now well established that iron bioavailability from habitual Indian diets is low due to high phytate and low ascorbic acid/iron ratios. These factors determine iron bioavailability and the RDA. There are striking differences in the iron RDAs among the physiological groups, which need to be validated. The other dietary factors affecting iron status are inadequate intake of folic acid and vitamins B(12), A, C and other vitamins of the B-complex group. Chronic low grade inflammation and infections, and malaria also contribute significantly to iron malnutrition. Recent evidence of the interaction of hepcidin (iron hormone) and inflammatory stimuli on iron metabolism has opened new avenues to target iron deficiency anaemia. Food-based approaches to increase the intake of iron and other haematopoietic nutrients through dietary diversification and provision of hygienic environment are important sustainable strategies for correction of iron deficiency anaemia.

Iron-zinc interaction during uptake in human intestinal Caco-2 cell line: kinetic analyses and possible mechanism.

Iron and zinc interact at the enterocyte during absorption, but the mechanism(s) remain elusive. The aim was, therefore, to understand the mechanism of interaction using kinetic analyses of iron and zinc uptake, individually and in combination under normal and altered cellular mineral concentrations in human intestinal Caco-2 cell line. Striking differences in kinetic parameters were observed between iron and zinc uptake. Iron uptake followed a two-component model, while zinc uptake followed a three-component model. Iron uptake had a Km of 3.6 microM and Vmax of 452 pmol/mg protein/min, while zinc uptake had a Km of 42 microM and Vmax of 3.09 pmol/mg protein/min. Zinc dose-dependently inhibited iron uptake through mixed-inhibition but iron marginally increased zinc uptake. Cellular zinc repletion doubled iron uptake and eliminated inhibition, but zinc depletion decreased iron uptake. Iron pre-treatment had no effect on zinc uptake. Based on these results, a two-transporter model of iron uptake, comprising the apical iron uptake transporter divalent metal ion transporter-1 (DMT-1) and an unknown putative transporter was derived. This model for DMT-1 was verified by immunoblotting. These results implied that cellular zinc status profoundly influenced iron uptake and its interactions with zinc during uptake. DMT-1 might not simultaneously transport iron and zinc, providing a mechanistic basis for observed interactions.

Food synergies for improving bioavailability of micronutrients from plant foods.

Plant foods are endowed with micronutrients but an understanding of bioavailability is essential in countries primarily dependent on plant based foods. Bioavailability depends majorly on food synergies. This review examines the nature of certain food synergies and methods to screen and establish it as a strategy to control micronutrient deficiency in the populations. Strong evidence on the synergistic effect of inclusion of vitamin C rich fruits and non-vegetarian foods in enhancing the bioavailability of iron has been demonstrated. Fat is found to be synergistic for vitamin A absorption. Red wine and protein have been explored for zinc absorption and effect of fat has been studied for vitamin D. Methods for screening of bioavailability, and biomarkers to demonstrate the synergistic effects of foods are required. Translation of food synergy as a strategy requires adaptation to the context and popularization of intelligent food synergies.

Gastric digestion of pea ferritin and modulation of its iron bioavailability by ascorbic and phytic acids in caco-2 cells.

AIM: To understand the digestive stability and mechanism of release and intestinal uptake of pea ferritin iron in caco-2 cell line model. METHODS: Pea seed ferritin was purified using salt fractionation followed by gel filtration chromatography. The bioavailability of ferritin iron was assessed using coupled in vitro digestion/Caco-2 cell model in the presence or absence of ascorbic acid and phytic acid. Caco-2 cell ferritin formation was used as a surrogate marker of iron uptake. Structural changes of pea ferritin under simulated gastric pH were characterized using electrophoresis, gel filtration and circular dichroism spectroscopy. RESULTS: The caco-2 cell ferritin formation was significantly increased (P<0.001) with FeSO(4) (19.3 +/- 9.8 ng/mg protein) and pea ferritin (13.9 +/- 6.19 ng/mg protein) compared to the blank digest (3.7 +/- 1.8 ng/mg protein). Ascorbic acid enhanced while phytic acid decreased the pea ferritin iron bioavailability. However, either in the presence or absence of ascorbic acid, the ferritin content of caco-2 cells was significantly less with pea ferritin than with FeSO(4). At gastric pH, no band corresponding to ferritin was observed in the presence of pepsin either on native PAGE or SDS-PAGE. Gel filtration chromatography and circular dichroism spectroscopy revealed a pH dependent loss of quaternary and secondary structure. CONCLUSION: Under gastric conditions, the iron core of pea ferritin is released into the digestive medium due to acid induced structural alterations and dissociation of protein. The released iron interacts with dietary factors leading to modulation of pea ferritin iron bioavailability, resembling the typical characteristics of non-heme iron.

Evidence for a sequential transfer of iron amongst ferritin, transferrin and transferrin receptor during duodenal absorption of iron in rat and human.

AIM: To elucidate the sequential transfer of iron amongst ferritin, transferrin and transferrin receptor under various iron status conditions. METHODS: Incorporation of 59Fe into mucosal and luminal proteins was carried out in control WKY rats. The sequential transfer of iron amongst ferritin, transferrin and transferrin receptor was carried out in iron deficient, control and iron overloaded rats. The duodenal proteins were subjected to immunoprecipitation and quantitation by specific ELISA and in situ localization by microautoradiography and immunohistochemistry in tandem duodenal sections. Human duodenal biopsy (n = 36) collected from subjects with differing iron status were also stained for these proteins. RESULTS: Ferritin was identified as the major protein that incorporated iron in a time-dependent manner in the duodenal mucosa. The concentration of mucosal ferritin was significantly higher in the iron excess group compared to control, iron deficient groups (731.5 +/- 191.96 vs 308.3 +/- 123.36, 731.5 +/- 191.96 vs 256.0 +/- 1.19, P < 0.005), while that of luminal transferrin which was significantly higher than the mucosal did not differ among the groups (10.9 +/- 7.6 vs 0.87 +/- 0.79, 11.1 +/- 10.3 vs 0.80 +/- 1.20, 6.8 +/- 4.7 vs 0.61 +/- 0.63, P < 0.001). In situ grading of proteins and iron, and their superimposition, suggested the occurrence of a sequential transfer of iron. This was demonstrated to occur through the initial binding of iron to luminal transferrin then to absorptive cell surface transferrin receptors. The staining intensity of these proteins varied according to the iron nutrition in humans, with intense staining of transferrin receptor observed in iron deficient subjects. CONCLUSION: It is concluded that the intestine takes up iron through a sequential transfer involving interaction of luminal transferrin, transferrin-transferrin receptor and ferritin.

Integration to Implementation and the Micronutrient Forum: A Coordinated Approach for Global Nutrition. Case Study Application: Safety and Effectiveness of Iron Interventions.

Paramount among the challenges to our ability to address the role of food and nutrition in health promotion and disease prevention is how to design and implement context-specific interventions and guidance. The Integration to Effective Implementation (I-to-I) concept is intended to address the complexities of the global health context through engagement of the continuum of stakeholders involved in the food and nutrition enterprise. The 2014 Micronutrient Forum (MNF) Global Conference held in Addis Ababa, Ethiopia, in June 2014 offered the opportunity to apply the I-to-I approach with the use of current concerns about the safety and effectiveness of interventions to prevent and treat iron deficiency (ID) as a case study. ID is associated with a range of adverse outcomes, especially in pregnant and nonpregnant women, infants, and primary school-age children. Strategies to combat ID include iron supplementation, multiple micronutrient powders, and food-based interventions to enhance dietary iron intake. Recent reports indicate potential increased adverse risks when iron is provided in areas with high infection burdens (e.g., malaria). This paradox has weakened iron intervention programs. Furthermore, the selection and interpretation of available biomarkers for assessing iron nutrition have been found to be compromised by the inflammatory process. These issues highlight the need for a comprehensive approach that considers basic biology, assessment, interventions, and how these can be translated into appropriate programs and policies. The application of the I-to-I with the use of the MNF offered an opportunity to explore how that might be achieved.

Double fortified salt at crossroads.

Iron Deficiency Anemia (IDA) and Iodine Deficiency Disorders (IDD) are the major public health problems often co-existing in many regions in our country. National Institute of Nutrition (NIN) has promoted the technology of double fortification of common salt with iodine and iron as a strategy to control both deficiencies under food-based approaches. Two other formulations of double fortified salt (DFS) have been subsequently developed by other agencies. NIN formulation & Nutrisalt have a stabilizer/promoter to maintain the stability of iodine in the presence of iron. The Micronutrient Initiative (MI) formulation uses physical separation of iodine by microencapsulation. NIN carried out extensive studies on stability, bioavailability, acceptability, safety and impact (including in community) of DFS. Feasibility both at factory level production and community level implementation have been worked out. MI salt had also undergone stability, acceptability and impact studies. No data is reported on the stability of Nutrisalt except that good stability is claimed in the available reports. In principle, the strategy of double fortification of salt with iron and iodine is sound with uniformly good impact on urinary iodine excretion and prevention of anemia. However, striking increments in hemoglobin (Hb) were not readily demonstrated since the intended purpose of DFS was only to provide iron at maintenance level and not therapeutic level. Complexities in the experimental designs, confounding variables and quality of the ingredients in salts also contributed to difficulties in interpretation of Hb status in studies involving DFS. Along with improvements contemplated in formulation to enhance the stability and bioavailibility, DFS should be able to fulfil the promise and realise its potential in reducing iron and iodine deficiency amongst our poor population in the next few years.

Iron dependence and zinc inhibition of duodenal cytosolic aconitase of rat.

The response of duodenal cytosolic aconitase (c-aconitase) to oral repletion of graded doses of iron (Fe) during Fe-deficiency was studied in rats (WNIN strain). In addition, in vitro effect of zinc (Zn) on the enzyme activity was studied using duodenal cytosol. Iron-depleted male rats were orally repleted with either 100 or 190 or 370 microg of Fe/day (n=6, each) for 2 weeks. Fe repletion was found to increase linearly the activity of duodenal c-aconitase along with the indicators of iron status. The correlation coefficient (r) between c-aconitase and haemoglobin and mucosal ferritin was 0.6453 and 0.8441, respectively. The effects of zinc (0-40 microM) in vitro on the kinetics of c-aconitase from iron-replete stock diet fed rats (n=4) showed that Zn competitively inhibited the enzyme with a Ki (app.) of 28 microM. These observations suggest that c-aconitase is a critical target involved in the assimilation of Fe and excess dietary Zn can result in negative interactions.

Coordinate expression and localization of iron and zinc transporters explain iron-zinc interactions during uptake in Caco-2 cells: implications for iron uptake at the enterocyte.

Iron and zinc have diverse and important physiological functions. Yet, the mechanism of their absorption at the intestine remains controversial and is confounded by the fact that many studies have shown, to varying extents, that they inhibit the absorption of each other. We have studied the expression of iron and zinc transporters and storage proteins, and their regulation, in Caco-2 cells, an established enterocyte model, under normal culture conditions and under conditions of iron and zinc depletion and supplementation using a combination of immunoblotting, confocal microscopy and reverse transcriptase polymerase chain reaction. We show that divalent metal transporter-1 (DMT-1) delocalizes from the plasma membrane upon iron or zinc depletion, but its apical abundance increases with zinc supplementation. This translocation of DMT-1 coincides with an increase in iron uptake upon zinc supplementation, as previously reported by us. FPN-1 expression increases upon zinc supplementation and decreases with iron or zinc depletion, effluxing the excess sequestered iron and thus maintaining cellular iron homeostasis. Zinc influx transporters Zip-1 and Zip-14 and efflux transporters ZnT-1 and ZnT-4 are coordinately regulated under conditions of zinc supplementation and depletion to ensure cellular zinc homeostasis. We have previously reported that iron uptake can entail two transporters and that zinc noncompetitively inhibits iron uptake in Caco-2 cells. We now provide evidence that this inhibition is independent of DMT-1 and that Zip-14 may be a relevant iron transporter. These new observations provide experimental support to this two-transporter model of iron uptake and give mechanistic insight to iron-zinc interactions during uptake at the enterocyte.

Infertility in WNIN Obese Mutant Rats-Causes?

We are maintaining two obese mutant rat strains (WNIN/Ob and WNIN/GR-Ob) in our animal facility since 1997. These rat colonies are perpetuated by crossing heterozygous littermates, since the obese phenotypes of both genders turned out be infertile. The present study revealed the reasons for this infertility. The male obese rats, though appeared normal in terms of sperm count, sperm motility and testis histology, however found wanting in terms of libido. This appeared to be due to low circulating testosterone levels seen in these animals, which should also account for low testis and accessory gland weights seen in them. The females exhibited delayed puberty, in terms of days taken for opening of vagina, irregular oestrus cycles and had small ovaries and short and stumpy uterine horns. The FSH peak observed in control lean animals during oestrus stage of the sexual cycle and also the E2 peak of normal oestrus cycle was conspicuously absent in these animals. They also showed elevated levels of progesterone throughout the sexual cycle. Thus the infertility seen in these mutants could be attributed to their abnormal gonadosteroid levels and the resulting anatomical and physiological defects.

Bioavailability of iron and zinc from multiple micronutrient fortified beverage premixes in Caco-2 cell model.

Iron and zinc deficiencies are the most prevalent nutrient deficiencies worldwide. They often coexist as the dietary factors, especially phytate, which impairs iron absorption also affects zinc absorption. Therefore, suitable strategies are required to control multiple micronutrient deficiencies in populations that subsist on high-phytate foods such as the whole wheat flour based Indian bread (chapatti). The objective of the study, therefore, was to test the bioavailability of iron and zinc in 2 multiple micronutrient beverage premixes in the absence and presence of chapatti. The premix-1 contained iron, zinc, and vitamin A while premix-2 contained all micronutrients in premix-1, plus folic acid and ascorbic acid. Ferritin induction and (65)Zn uptake were assessed using coupled in vitro digestion/Caco-2 cell line model as the surrogate markers of iron and zinc bioavailability, respectively. The results show that iron bioavailability from premixes-1 and 2 was similar in the absence of chapatti. However, premix-2 showed significantly higher iron bioavailability compared to premix-1 in the presence of chapatti. In contrast, the zinc uptake was similar from both premixes-1 and 2 in the absence or presence of chapatti. These results suggest that both the premixes provide bioavailable minerals, but premix-2 appears to be promising in the presence of foods that have high phytate.

Prevalence of clinical and sub-clinical vitamin A deficiency among rural preschool children of West Bengal, India.

A community based cross-sectional study was carried out in rural areas of West Bengal with the aim to assess the prevalence of vitamin A deficiency (VAD) among rural preschool children. Clinical examination was carried out on 9,228 children for the signs and symptoms of VAD and a sub-sample of 590 children were covered for the estimation of blood vitamin A levels using dried blood spot (DBS) method. The prevalence of Bitot's spots was 0.6% (95% CI=0.44, 0.76), which is more than the public health significance, and it increased with increase in age. The prevalence was significantly higher (P<0.001) among boys (0.8%) as compared to girls (0.4%). The proportion of children with subclinical vitamin A deficiency (blood vitamin A < 20 ug/dL) was 61% (95% CI: 52.3-65.1), and it was significantly (P<0.01) higher among the children of lower socioeconomic communities.