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The American Journal of Clinical Nutrition, 104 (1), ISSN:0002-9165, ISSN:1938-3207

Background Sodium iron edetic acid (NaFeEDTA) might be a more bioavailable source of iron than electrolytic iron, when added to maize flour. We aimed to assess the effect, on children's iron status, of consumption of whole maize flour fortified with iron as NaFeEDTA or electrolytic iron. Methods 516 children, aged 3-8 years, from four schools in Marafa, Kenya, were randomly assigned to four groups. All were given the same amount of porridge five times a week. The porridge for one group was made from unfortified whole maize flour; for the other three groups it was fortified with either high-dose NaFeEDTA (56 mg/kg), low-dose NaFeEDTA (28 mg/kg), or electrolytic iron (56 mg/kg). Concentrations of haemoglobin, plasma ferritin, and transferrin receptor were analysed in samples taken at baseline and at the end of the 5-month intervention. The primary outcome was iron-deficiency anaemia. We analysed data on an intention-to-treat basis. This trial is registered with ClinicalTrials.gov, number NCT00386074. Findings The prevalence of iron-deficiency anaemia in children given unfortified flour was 10%. Compared with placebo, the prevalence of iron-deficiency anaemia in children given flour fortified with high-dose NaFeEDTA, low-dose NaFeEDTA, and electrolytic iron changed by -89% (95% CI -97% to -49%), -48% (-77% to 20%), and 59% (-18% to 209%), respectively. Consumption of high-dose NaFeEDTA improved all measured iron-status indicators. Low-dose NaFeEDTA decreased the prevalence of iron deficiency but did not noticeably change the prevalence of anaemia. Electrolytic iron did not improve any of these iron-status indicators. Children who were iron-deficient at baseline benefited more from high-dose and low-dose NaFeEDTA than those with sufficient iron at baseline. Interpretation Consumption of whole maize flour fortified with NaFeEDTA caused modest, dose-dependent improvements in children's iron status. Fortification with electrolytic iron did not improve their iron status. Therefore, in high-phytate flours, NaFeEDTA is more suitable than electrolytic iron for supplementation of iron in the diet.

Background: Our group and many others have used the relativedose- response (RDR) test and the modified-RDR (MRDR) test as proxy indicators of liver stores of vitamin A. However, we have become concerned about the validity of these indicators. Objective: Simulation models were used to assess effects of random variations in serum retinol concentration on the RDR and to assess effects of group differences in serum retinol concentration on the distribution of RDR and MRDR values. Design: Random and independent samples were drawn from normally distributed, computer-generated numbers whose distributions simulated serum concentrations of retinol and 3,4-didehydroretinol as obtained from published reports. The resulting data sets were used to compute surrogateRDRorMRDRvalues. In model 1, the relation between serum concentrations of retinol and RDR was examined within a fictitious population. In models 2 and 3, fictitious populations with different distributions of serum retinol concentration were compared with respect to their RDR and MRDR values. Results: Simulated RDR values and serum retinol concentrations were negatively related. Models 2 and 3 showed that group differences in serum retinol concentrations necessarily produced group differences in mean RDR or MRDR values. A mathematical artefact may explain the negative relation reported between MRDR and serum retinol concentration, and it dictates that this relation will necessarily vary between populations with different degrees of vitamin A deficiency. Conclusion: A continued search for alternative blood indicators of liver stores of vitamin A is needed.

Objectives: Hematologic and non-hematologic benefits from iron supplementation are chiefly seen in iron deficient individuals; concerns that iron might promote infection especially in non-iron deficient individuals have complicated global anemia control policies, particularly in malaria-endemic settings. Iron homeostasis, including intestinal absorption, is controlled by hepcidin. Hepcidin is regulated by iron, erythropoietic drive, and inflammation, suggesting its potential utility to appraise iron status and thus guide iron supplementation. Methods: In 1338 African pre-school children we evaluated the Area Under the ROC Curve (AUCROC) for plasma hepcidin concentration as a diagnostic test of iron status, anemia type and erythrocyte incorporation of oral iron, determining and modeling the effects of cutoffs. Results: Hepcidin detected iron deficiency with an AUCROC = 0.85 (optimal sensitivity/ specificity at a cutoff of 5.5 ng/ml); this was not significantly affected by gender, wasting, malaria or carriage of inherited red cell disorders. In anemic children, hepcidin distinguished iron deficiency anemia from anemia of inflammation (AUCROC=0.89, optimal sensitivity/specificity cutoff 5.4 ng/ml). Hepcidin was the best predictor for >20% incorporation into erythrocytes of orally-administered 57Fe (AUCROC=0.90, optimal sensitivity/ specificity cutoff P. falciparum and 86% of children with anemia of inflammation would have avoided iron. Conclusions: In African children, hepcidin ascertains iron status, distinguishes iron deficiency anemia from anemia of inflammation, and hence could guide iron supplementation toward groups in whom it will likely be beneficial and safe.

Tumour necrosis factor (TNF) is central to the immune response to Plasmodium infection. Its plasma concentration is influenced by allele variants in the promoter region of TNF. The study’s objectives were to assess TNF allele variants (TNF −1031, TNF −308): (1) modulation of malaria rates in young Tanzanian children; (2) modulation of the severity of malaria as indicated by haemoglobin concentrations at the time of presentation with febrile episodes; and (3) the association between Plasmodium infection and haemoglobin concentration in symptomless parasite carriers. Data from a placebo-controlled trial in which 612 Tanzanian children aged 6–60 months with height-for-age z-score in the range −3 SD to 1.5 SD was utilised. Those with Plasmodium infection at baseline were treated with artemether-lumefantrine. An episode of malaria was predefined as current Plasmodium infection with an inflammatory response (axillary temperature ≥37.5°C or whole blood C-reactive protein concentration ≥8 mg/L) in children reported sick. Linkage disequilibrium (LD) pattern assessment as well as haplotype analysis was conducted using HAPLOVIEW. Cox regression models used in the primary analysis accounted for multiple episodes per child. Genotyping of 94.9% (581/612) children for TNF −1031 (TNF −1031T>C); allele frequency was 0.39. Corresponding values for rs1800629 (TNF −308G>A) were 95.4% (584/612) and 0.17. Compared to the wild type genotype (TT), malaria rates were increased in the TNF −1031CC genotype (hazard ratio, HR [95% CI]: 1.41 [1.01‒1.97] and 1.31 [0.97‒1.76] for crude analysis and adjusting for pre-specified baseline factors, respectively) but decreased in those with the TNF −308AA genotype (corresponding HR: 0.13 [0.02‒0.63] and 0.16 [0.04‒0.67]). These associations were weaker when analysing first episodes of malaria (P value −0.59 and 0.38, respectively). No evidence that allele variants of TNF −1031 and TNF −308 affected haemoglobin concentration at first episode of malaria, or that they modified the association between Plasmodium infection and haemoglobin concentrations at baseline was observed. In this cohort of Tanzanian children, the TNF −1031CC genotype was associated with increased rates of malarial episodes, whereas the TNF −308AA genotype was associated with decreased rates.

Background Iron-deficient erythropoiesis results in excess formation of zinc protoporphyrin (ZPP), which can be measured instantly and at low assay cost using portable haematofluorometers. ZPP is used as a screening marker of iron deficiency in individual pregnant women and children, but also to assess population iron status in combination with haemoglobin concentration. We examined associations between ZPP and disorders that are common in Africa. In addition, we assessed the diagnostic utility of ZPP (measured in whole blood and erythrocytes), alone or in combination with haemoglobin concentration, in detecting iron deficiency (plasma ferritin concentration 70 μmol/mol haem) resulted in gross overestimates of the prevalence of iron deficiency. Conclusions Erythrocyte ZPP has limited value to rule out iron deficiency when used for screening in conditions with a low prevalence (e.g., 10%). ZPP is of unreliable diagnostic utility when discriminating between pregnant women with and without iron deficiency. Based on these findings, guidelines on the use of ZPP to assess iron status in individuals or populations of pregnant women need review. Trial registration NCT01308112 (2 March 2011).

Background: Serum transferrin receptor concentrations indicate both erythropoietic activity and the deficit of functional iron in the erythron. In contrast with serum ferritin concentrations, serum transferrin receptor concentrations are not or are only marginally influenced by the inflammatory response to infection. Objective: We assessed iron status and examined the relation between serum transferrin receptor concentrations and malaria in children aged 2-36 mo who were asymptomatic for malaria. Design: This was a community-based cluster survey (n = 318). Results: Prevalences of malaria, anemia (hemoglobin concentration

Plant signals from the Borssele nuclear power plant in the Netherlands were analyzed to investigate the characteristics of neutron flux fluctuation in the low-frequency range 0 to 0.5 Hz, focusing ...

Background: In malaria-endemic settings, asymptomatic parasitemia complicates the diagnosis of malaria. Histidine-rich protein 2 (HRP2) is produced by Plasmodium falciparum, and its plasma concentration reflects the total body parasite burden. We aimed to define the malaria-attributable fraction of severe febrile illness, using the distributions of plasma P. falciparum HRP2 (PfHRP2) concentrations from parasitemic children with different clinical presentations. Methods: Plasma samples were collected from and peripheral blood slides prepared for 1435 children aged 6−60 months in communities and a nearby hospital in northeastern Tanzania. The study population included children with severe or uncomplicated malaria, asymptomatic carriers, and healthy control subjects who had negative results of rapid diagnostic tests. The distributions of plasma PfHRP2 concentrations among the different groups were used to model severe malaria-attributable disease. Results:The plasma PfHRP2 concentration showed a close correlation with the severity of infection. PfHRP2 concentrations of >1000 ng/mL denoted a malaria-attributable fraction of severe disease of 99% (95% credible interval [CI], 96%–100%), with a sensitivity of 74% (95% CI, 72%–77%), whereas a concentration of 10% (95% CI, 3%–27%) of patients. Bacteremia was more common among patients in the lowest and highest PfHRP2 concentration quintiles. Conclusions: The plasma PfHRP2 concentration defines malaria-attributable disease and distinguishes severe malaria from coincidental parasitemia in African children in a moderate-to-high transmission setting.

This abstract is submitted as part of the round-table discussion sponsored by Sight and Life. A recent trial reinforced earlier concerns that iron supplementation can increase malaria rates. The World Health Organization subsequently restricted its recommendations in malaria-endemic areas from universal supplementation to targeted supplementation of iron-deficient children, but continues to advocate universal supplementation in pregnancy. Resurgent interest in iron has led to further studies to assess its safety, particularly in pregnant women; to identify markers for rapid, low-cost screening for deficiency; and to develop safe but efficacious iron interventions. The hepcidin-axis recently emerged as a newly discovered arm of the innate immune system. Hepcidin is now known to regulate iron absorption and metabolism, but also to mediate impaired recycling and absorption of iron in infections. Current evidence suggests that plasma hepcidin concentration may predict haematological and infectious responses to iron, at least in the short term, and that deliberately altering hepcidin concentrations may result in new strategies to control infections by Plasmodium and other iron-requiring pathogens. Folic acid supplementation continues to be recommended around conception and during pregnancy, and international agencies have recommended additional measures to increase the intake of folic acid. Plasmodium parasites can utilise exogenous folate, however, and several trials suggest that folic acid supplementation can reduce the efficacy of antifolate drugs used for malaria control. A better understanding is required of the controversies of interventions to increase folate status and the safety of interventions to improve folate status in malaria-endemic countries.

BACKGROUND: The efficacy of preventive zinc supplementation against diarrhea and respiratory illness may depend on simultaneous supplementation with other micronutrients. We aimed to assess the effect of supplementation with zinc and multiple micronutrients on diarrhea and other causes of non-malarial morbidity. METHODS AND FINDINGS: Rural Tanzanian children (n = 612) aged 6-60 months and with height-for-age z-score < -1.5 SD were randomized to daily supplementation with zinc (10 mg) alone, multi-nutrients without zinc, multi-nutrients with zinc, or placebo. Children were followed for an average of 45 weeks. During follow-up, we recorded morbidity episodes. We found no evidence that concurrent supplementation with multi-nutrients influenced the magnitude of the effect of zinc on rates of diarrhea, respiratory illness, fever without localizing signs, or other illness (guardian-reported illness with symptoms involving skin, ears, eyes and abscesses, but excluding trauma or burns). Zinc supplementation reduced the hazard rate of diarrhea by 24% (4%-40%). By contrast, multi-nutrients seemed to increase this rate (HR; 95% CI: 1.19; 0.94-1.50), particularly in children with asymptomatic Giardia infection at baseline (2.03; 1.24-3.32). Zinc also protected against episodes of fever without localizing signs (0.75; 0.57-0.96), but we found no evidence that it reduced the overall number of clinic visits. CONCLUSIONS: We found no evidence that the efficacy of zinc supplements in reducing diarrhea rates is enhanced by concurrent supplementation with other micronutrients. By reducing rates of fever without localizing signs, supplementation with zinc may reduce inappropriate drug use with anti-malarial medications and antibiotics. TRIAL REGISTRATION: ClinicalTrials.gov NCT00623857.

Objectives: To measure the effect of daily consumption of provitamin A-biofortified cassava on vitamin A status in children aged 5-13 years. Methods: Mild-to-moderate vitamin A deficient children (n=342) were randomly allocated to groups receiving: 1) 375 g of white cassava and placebo supplement; 2) 375 g of white cassava and a supplement of β-carotene (1,054 μg); 3) 375 g of biofortified cassava and placebo supplement. Children received the intervention 6 days/week for 18.5 weeks. Field staff and participants were blinded to supplementation. Cooked cassava was mashed with salt and 4 g of oil per portion. Biofortified cassava supplied 208 μg RAE, which is ~50% of the age-specific estimated average Conference Abstract Talsma et al.; EJNFS, 5(5): 836-837, 2015; Article no.EJNFS.2015.312 837 requirement for vitamin A for children. The primary endpoint was serum retinol concentration and secondary endpoint was serum β-carotene concentration, both at end of intervention; in the analysis, we adjusted for sex and serum concentrations at baseline of retinol, C-reactive protein and α1-acid-glycoprotein. Results: Complete data were collected for 337 children. Compliance to cassava feeding was similar between treatment groups. Preliminary results showed that consumption of biofortified cassava and β-carotene supplementation resulted in a similar increase in retinol concentrations (for both interventions, mean: 0.81 μmol/L versus 0.77 μmol/L; difference, 95% CI: 0.04 μmol/L, 0.00─0.07 μmol/L) but in a different increase in serum β-carotene concentration (for β-carotene supplement group, mean: 0.25 μmol/L (95% CI: 0.17─0.33), for biofortified cassava group, mean: 0.81 μmol/L (95% CI: 0.73-0.88)) Conclusions: Provitamin A-biofortified cassava improves the vitamin A status of primary school children in Kenya. © 2015 Talsma et al.; This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Hans Verhoef and colleagues report findings from a randomized trial conducted among Tanzanian children at high risk for malaria. Children in the trial received either daily oral supplementation with either zinc alone, multi-nutrients without zinc, multi-nutrients with zinc, or placebo. The investigators did not find evidence from this study that zinc or multi-nutrients protected against malaria episodes., Background It is uncertain to what extent oral supplementation with zinc can reduce episodes of malaria in endemic areas. Protection may depend on other nutrients. We measured the effect of supplementation with zinc and other nutrients on malaria rates. Methods and Findings In a 2×2 factorial trial, 612 rural Tanzanian children aged 6–60 months in an area with intense malaria transmission and with height-for-age z-score≤−1.5 SD were randomized to receive daily oral supplementation with either zinc alone (10 mg), multi-nutrients without zinc, multi-nutrients with zinc, or placebo. Intervention group was indicated by colour code, but neither participants, researchers, nor field staff knew who received what intervention. Those with Plasmodium infection at baseline were treated with artemether-lumefantrine. The primary outcome, an episode of malaria, was assessed among children reported sick at a primary care clinic, and pre-defined as current Plasmodium infection with an inflammatory response, shown by axillary temperature ≥37.5°C or whole blood C-reactive protein concentration ≥8 mg/L. Nutritional indicators were assessed at baseline and at 251 days (median; 95% reference range: 191–296 days). In the primary intention-to-treat analysis, we adjusted for pre-specified baseline factors, using Cox regression models that accounted for multiple episodes per child. 592 children completed the study. The primary analysis included 1,572 malaria episodes during 526 child-years of observation (median follow-up: 331 days). Malaria incidence in groups receiving zinc, multi-nutrients without zinc, multi-nutrients with zinc and placebo was 2.89/child-year, 2.95/child-year, 3.26/child-year, and 2.87/child-year, respectively. There was no evidence that multi-nutrients influenced the effect of zinc (or vice versa). Neither zinc nor multi-nutrients influenced malaria rates (marginal analysis; adjusted HR, 95% CI: 1.04, 0.93–1.18 and 1.10, 0.97–1.24 respectively). The prevalence of zinc deficiency (plasma zinc concentration, Editors' Summary Background Malaria is a serious global public-health problem. Half of the world's population is at risk of this parasitic disease, which kills a million people (mainly children living in sub-Saharan Africa) every year. Malaria is transmitted to people through the bites of infected night-flying mosquitoes. Soon after entering the human body, the parasite begins to replicate in red blood cells, bursting out every 2–3 days and infecting more red blood cells. The presence of the parasite in the blood stream (parasitemia) causes malaria's characteristic recurring fever and can cause life-threatening organ damage and anemia (insufficient quantity of red blood cells). Malaria transmission can be reduced by using insecticide sprays to control the mosquitoes that spread the parasite and by avoiding mosquito bites by sleeping under insecticide-treated bed nets. Effective treatment with antimalarial drugs can also reduce malaria transmission. Why Was This Study Done? One reason why malaria kills so many children in Africa is poverty. Many children in Africa are malnourished, and malnutrition—in particular, insufficient micronutrients in the diet—impairs the immune system, which increases the frequency and severity of many childhood diseases. Micronutrients are vitamins and minerals that everyone needs in small quantities for good health. Zinc is one of the micronutrients that helps to maintain a healthy immune system, but zinc deficiency is very common among African children. Zinc supplementation has been shown to reduce the burden of diarrhea in developing countries, so might it also reduce the burden of malaria? Unfortunately, the existing evidence is confusing—some trials show that zinc supplementation protects against malaria but others show no evidence of protection. One possibility for these conflicting results could be that zinc supplementation alone is not sufficient—supplementation with other micronutrients might be needed for zinc to have an effect. In this randomized trial (a study that compares the effects of different interventions in groups that initially are similar in all characteristics except for intervention), the researchers investigate the effect of supplementation with zinc alone and in combination with other micronutrients on the rate of uncomplicated (mild) malaria among children living in Tanzania. What Did the Researchers Do and Find? The researchers enrolled 612 children aged 6–60 months who were living in a rural area of Tanzania with intense malaria transmission and randomly assigned them to receive daily oral supplements containing zinc alone, multi-nutrients (including iron) without zinc, multi-nutrients with zinc, or a placebo (no micronutrients). Nutritional indicators (including zinc concentrations in blood plasma) were assessed at baseline and 6–10 months after starting the intervention. During the study period, there were 1,572 malaria episodes. The incidence of malaria in all four intervention groups was very similar (about three episodes per child-year), and there was no evidence that multi-nutrients influenced the effect of zinc (or vice versa). Moreover, none of the supplements had any effect on malaria rates when compared to the placebo, even though the occurrence of zinc deficiency was strongly reduced by zinc supplementation. In a secondary analysis in which they analyzed their data by iron status at baseline, the researchers found that multi-nutrient supplementation increased the overall number of malaria episodes in children with iron deficiency by 41%, whereas multi-nutrient supplementation had no effect on the number of malaria episodes among children who were iron-replete at baseline. What Do These Findings Mean? In this study, the researchers found no evidence that zinc supplementation protected against malaria among young children living in Tanzania when given alone or in combination with other multi-nutrients. However, the researchers did find some evidence that multi-nutrient supplementation may increase the risk of malaria in children with iron deficiency. Because this finding came out of a secondary analysis of the data, it needs to be confirmed in a trial specifically designed to assess the effect of multi-nutrient supplements on malaria risk in iron-deficient children. Nevertheless, it is a potentially worrying result because, on the basis of evidence from a single study, the World Health Organization currently recommends that regular iron supplements be given to iron-deficient children in settings where there is adequate access to anti-malarial treatment. This recommendation should be reconsidered, suggest the researchers, and the safety of multi-nutrient mixes that contain iron and that are dispensed in countries affected by malaria should also be carefully evaluated. Additional Information Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001125. Information is available from the World Health Organization on malaria (in several languages), on micronutrients, and on zinc deficiency; the 2010 World Malaria Report provides details of the current global malaria situation The US Centers for Disease Control and Prevention provide information on malaria (in English and Spanish), including a selection of personal stories about malaria Information is available from the Roll Back Malaria Partnership on the global control of malaria and on malaria in Africa The Malaria Centre at the UK London School of Hygiene & Tropical Medicine develops tools, techniques, and knowledge about malaria, and has a strong emphasis on teaching, training, and translating research outcomes into practice The Micronutrient Initiative, the Global Alliance for Improved Nutrition, and the Flour Fortification Initiative are not-for-profit organizations dedicated to ensuring that people in developing countries get the minerals and vitamins they need to survive and thrive The International Zinc Nutrition Consultative Group (iZiNCG) is a non-profit organization that aims to promote and assist efforts to reduce zinc deficiency worldwide, through advocacy efforts, education, and technical assistance MedlinePlus provides links to additional information on malaria (in English and Spanish)

Background It is controversial to what degree α+-thalassaemia protects against episodes of uncomplicated malaria and febrile disease due to infections other than Plasmodium. Methods In Tanzania, in children aged 6-60 months and height-for-age z-score < -1.5 SD (n = 612), rates of fevers due to malaria and other causes were compared between those with heterozygous or homozygotes α+-thalassaemia and those with a normal genotype, using Cox regression models that accounted for multiple events per child. Results The overall incidence of malaria was 3.0/child-year (1, 572/526 child-years); no differences were found in malaria rates between genotypes (hazard ratios, 95% CI: 0.93, 0.82-1.06 and 0.91, 0.73-1.14 for heterozygotes and homozygotes respectively, adjusted for baseline factors that were predictive for outcome). However, this association strongly depended on age: among children aged 6-17 months, those with α+-thalassaemia experienced episodes more frequently than those with a normal genotype (1.30, 1.02-1.65 and 1.15, 0.80-1.65 for heterozygotes and homozygotes respectively), whereas among their peers aged 18-60 months, α+-thalassaemia protected against malaria (0.80, 0.68-0.95 and 0.78, 0.60-1.03; p-value for interaction 0.001 and 0.10 for hetero- and homozygotes respectively). No effect was observed on non-malarial febrile episodes. Conclusions In this population, the association between α+-thalassaemia and malaria depends on age. Our data suggest that protection by α+-thalassaemia is conferred by more efficient acquisition of malaria-specific immunity.

Background Asymptomatic carriage of Giardia intestinalis is highly prevalent among children in developing countries, and evidence regarding its role as a diarrhea-causing agent in these settings is controversial. Impaired linear growth and cognition have been associated with giardiasis, presumably mediated by malabsorption of nutrients. In a prospective cohort study, we aim to compare diarrhea rates in pre-school children with and without Giardia infection. Because the study was conducted in the context of an intervention trial assessing the effects of multi-nutrients on morbidity, we also assessed how supplementation influenced the relationship between Giardia and diarrhoea rates, and to what extent Giardia modifies the intervention effect on nutritional status. Methods and Findings Data were collected in the context of a randomized placebo-controlled efficacy trial with 2×2 factorial design assessing the effects of zinc and/or multi-micronutrients on morbidity (n = 612; height-for-age z-score, Author Summary Giardia intestinalis is a well-known cause of diarrhea in industrialized countries. In children in developing countries, asymptomatic infections are common and their role as cause of diarrhea has been questioned. In a cohort of rural Tanzanian pre-school children, we assessed the association between the presence of Giardia at baseline and subsequent diarrhea risk. The study was conducted in the context of a randomised trial assessing the effect of supplementation with zinc and other micro-nutrients on malaria, and half of the children daily received a multi-nutrient supplement. Surprisingly, we found that the presence of Giardia at baseline was associated with a substantial reduction in diarrhea risk. Multivariate statistical analysis showed that this protection could not be explained by differences in age or walking distance to the dispensary between children with and without Giardia. Because we cannot exclude that children differed in other (unmeasured) characteristics, we cannot draw firm conclusions about the causality of the observed association, but our findings support the view that the parasite is not an important cause of diarrhea in highly endemic settings. Striking was that the Giardia-associated protection was lost when children received multi-nutrients. Our data do not provide information about the mechanisms involved, but suggest that multi-nutrients may influence the compositionor pathogenicity of intestinal biota.

BackgroundAn appropriate balance between pro-inflammatory and anti-inflammatory cytokines that mediate innate and adaptive immune responses is required for effective protection against human malaria and to avoid immunopathology. In malaria endemic countries, this immunological balance may be influenced by micronutrient deficiencies.MethodsPeripheral blood mononuclear cells from Tanzanian preschool children were stimulatedin vitrowithPlasmodium falciparum-parasitized red blood cells to determine T-cell responses to malaria under different conditions of nutrient deficiencies and malaria status.ResultsThe data obtained indicate that zinc deficiency is associated with an increase in TNF response by 37%; 95% CI: 14% to 118% and IFN-γ response by 74%; 95% CI: 24% to 297%. Magnesium deficiency, on the other hand, was associated with an increase in production of IL-13 by 80%; 95% CI: 31% to 371% and a reduction in IFN-γ production. These results reflect a shift in cytokine profile to a more type I cytokine profile and cell-cell mediated responses in zinc deficiency and a type II response in magnesium deficiency. The data also reveal a non-specific decrease in cytokine production in children due to iron deficiency anaemia that is largely associated with malaria infection status.ConclusionsThe pathological sequels of malaria potentially depend more on the balance between type I and type II cytokine responses than on absolute suppression of these cytokines and this balance may be influenced by a combination of micronutrient deficiencies and malaria status.

Background Deficiencies in vitamins and mineral elements are important causes of morbidity in developing countries, possibly because they lead to defective immune responses to infection. The aim of the study was to assess the effects of mineral element deficiencies on early innate cytokine responses to Plasmodium falciparum malaria. Methods Peripheral blood mononuclear cells from 304 Tanzanian children aged 6-72 months were stimulated with P. falciparum-parasitized erythrocytes obtained from in vitro cultures. Results The results showed a significant increase by 74% in geometric mean of TNF production in malaria-infected individuals with zinc deficiency (11% to 240%; 95% CI). Iron deficiency anaemia was associated with increased TNF production in infected individuals and overall with increased IL-10 production, while magnesium deficiency induced increased production of IL-10 by 46% (13% to 144%) in uninfected donors. All donors showed a response towards IL-1β production, drawing special attention for its possible protective role in early innate immune responses to malaria. Conclusions In view of these results, the findings show plasticity in cytokine profiles of mononuclear cells reacting to malaria infection under conditions of different micronutrient deficiencies. These findings lay the foundations for future inclusion of a combination of precisely selected set of micronutrients rather than single nutrients as part of malaria vaccine intervention programmes in endemic countries.

Contains fulltext : 80249.pdf (Publisher’s version ) (Closed access) Disturbances in iron homeostasis are frequently observed in individuals with malaria. To study the effect of malaria and its treatment on iron homeostasis and to provide a mechanistic explanation for observed alterations in iron distribution, we studied the course of the iron regulatory hormone hepcidin in anemic Tanzanian children with febrile Plasmodium falciparum malaria. Before initiation of antimalarial treatment, urinary concentrations of hepcidin were strongly elevated and were associated with iron maldistribution, as was suggested by the presence of hypoferremia and high serum concentrations of ferritin. Antimalarial treatment resulted in a rapid decrease in urinary concentrations of hepcidin and reversal of the hypoferremia. Exploration of regulatory pathways of hepcidin production by analysis of iron, erythropoietic, and inflammatory indices suggested that reduced erythropoietic activity and inflammation stimulated hepcidin production. We conclude that high concentrations of hepcidin explain the observed disturbances in host iron homeostasis associated with malaria and may contribute to malarial anemia and an impaired erythropoietic response to iron supplementation.

BACKGROUND: In hospital-based studies, alpha(+)-thalassemia has been found to protect against severe, life-threatening falciparum malaria. alpha(+)-Thalassemia does not seem to prevent infection or high parasite densities but rather limits progression to severe disease--in particular, severe malarial anemia. We assessed to what extent alpha(+)-thalassemia influences the association between mild, asymptomatic Plasmodium falciparum infection and hemoglobin concentration. METHODS: The study was based on 2 community-based surveys conducted among afebrile children (0.5-8 years old; n=801) in Kenya and Tanzania. RESULTS: Among children without inflammation (whole-blood C-reactive protein concentration

This study hypothesized that besides iron deficiency, intestinal parasites infection is also a determinant of anemia in schoolchildren in rural Vietnam.400 primary schoolchildren from 20 primary schools in Tam Nong district, a poor rural area in Vietnam, were randomly selected from enrollment lists. Venous blood (5ml) was collected in a cross sectional study and analyzed for hemoglobin (Hb), serum ferritin (SF), serum transferrin receptor (TfR), serum C-reactive protein (CRP) and total immunoglobulin E (IgE). Stools samples were examined for hookworm, Trichuris, and Ascaris infection. Logistic regression was used to assess the effect of intestinal parasites on anemia.The prevalence of anemia (Hb115g/l) was 25%. Iron deficiency (TfR8.5mg/L) occurred in 2% of the children. The prevalence of intestinal parasites was 92% with the highest prevalence for Trichuris (76%) and Ascaris (71%). More than 30% and 80% of the children showed an elevated CRP (or = 8 mg/L) and IgE (90 IU/ml) concentration. Anemia status was borderline significantly associated with SF and not associated with TfR and CRP. The prevalence odds ratio for Trichuris infection was 1.96 (95% CI 1.07-3.59) and 2.00 (95% CI 1.08-3.65) with iron deficiency reflected by TfR and SF, respectively.Anemia is highly prevalent among schoolchildren in Vietnam but may not be associated with iron deficiency. Trichuris infection is associated with a doubled risk of anemia, not mediated through iron deficiency. Chronic infection may play a role in anemia, but needs further investigation.

Schoolchildren in developing countries often have inadequate intakes of iron, due primarily to poor bioavailability. Increasing meat in the diet could improve both the amount of iron consumed and its availability. The effect of increases in intakes of meat and ascorbic acid on absorbed iron was investigated by theoretically modifying the habitual diet of rural Kenyan schoolchildren. The projected changes in the amount of absorbed iron and prevalence of inadequate iron intakes were calculated for 78 children (6–9 years of age). The prevalence of inadequate iron intakes decreased from 77% to 54% through the theoretical addition of 50 g beef or 100 mg ascorbic acid and to 23% through the addition of both to dinner each day. To reduce the prevalence of inadequate iron intake to 5%, the addition of 100 g meat plus 150 mg ascorbic acid would be necessary. The combined addition of meat and ascorbic acid to a meal has the potential to reduce the projected prevalence of inadequate iron intakes among these schoolchildren.

More information is needed on the efficacy of carotenoids from plant foods in improving vitamin A status.We aimed to quantify the efficacy of provitamin A-rich vegetables and fruit in improving vitamin A status.Breastfeeding women in 9 rural communes in Vietnam were randomly allocated to 1 of 4 groups: the vegetable group (n = 73), which ingested 5.6 mg beta-carotene/d from green leafy vegetables; the fruit group (n = 69), which ingested 4.8 mg beta-carotene/d from orange or yellow fruit; the retinol-rich group (n = 70), which ingested 610 microg retinol/d from animal foods and 0.6 mg beta-carotene/d; and the control group (n = 68), which ingested 0.4 mg beta-carotene/d. Meals of groups 1, 2, and 4 contained30 microg retinol/d. Lunch and dinner were provided 6 d/wk for 10 wk.Mean (95% CI) changes in serum retinol concentrations of the vegetable, fruit, retinol-rich, and control groups were 0.09 (0.03, 0.16), 0.13 (0.07, 0.19), 0.25 (0.17, 0.33), and 0.00 (-0.06, 0.06) micromol/L, respectively. Mean (95% CI) changes in breast-milk retinol concentrations were 0.15 (0.04, 0.27), 0.15 (0.02, 0.28), 0.48 (0.32, 0.64), and -0.06 (-0.21, 0.09) micromol/L, respectively. According to these findings, the equivalent of 1 microg retinol would be 12 microg beta-carotene (95% CI: 8, 22 microg) for fruit and 28 microg beta-carotene (17, 84 microg) for green leafy vegetables. Thus, apparent mean vitamin A activity of carotenoids in fruit and in leafy vegetables was 50% (95% CI: 27%, 75%) and 21% (7%, 35%), respectively, of that assumed.The bioavailability of carotenoids from vegetables and fruit is less than previously assumed.

The contribution of various factors to malnutrition, particularly stunting, may differ among areas and communities. This cross-sectional study aimed to estimate the level of malnutrition and identify factors associated with the high level of stunting in breast-fed infants aged 5-11 mo living in Dodota-Sire District, Ethiopia. Infants (n = 305) and their mothers were examined physically, and anthropometric and demographic data were collected. The content of zinc, calcium and copper in breast milk was measured, and data collected on the type, frequency of consumption, and time of introduction of supplementary feeding. Overall, 36% were stunted, 41% underweight and 13% wasted. The highest prevalence of malnutrition was seen in infants aged 9-11 mo. Among mothers, 27% had chronic energy deficiency (body mass index, 3 times/d, consuming > 600 mL/d or consuming cow's milk in addition to cereals and/or legumes had markedly higher length-for-age Z-scores than their peers fed less frequently, consuming less food or not consuming cow's milk [differences: 0.39, 95% confidence interval (Cl): 0.04-0.74; 0.17, 95% Cl: 0.02-0.32; 0.40, 95% Cl: 0.07-0.72, respectively]. Infants of mothers with low concentrations of zinc in their breast milk were more stunted. In conclusion, the quality and quantity of foods consumed by infants is insufficient to prevent stunting. Thus it is necessary to increase the,nutrient supply to infants by increasing intake and nutrient concentration of breast milk and of supplementary foods they consume, and by providing supplements to infants Where appropriate.

textabstractSpectacular progress has been made in the last decades in the global fight against deficiencies of iodine and vitamin A [1]. As a result, the number of people suffering from iodine deficiency has been reduced from about 1.5 billion in 1990 to about 0.5 billion now, almost entirely due to the introduction in many countries of what has been termed ‘universal salt iodization’. In addition, approximately one million child deaths may have been prevented between 1998 and 2000 by vitamin A supplementation [2]. The political and financial commitment that has allowed these achievements has been generated to a large extent by scientific studies that have shown the extent of human suffering caused by these deficiencies, and that have determined the potential health gains of interventions. Progress in eliminating deficiencies of other micronutrients, notably iron, has been much slower. About two billion people, or about one third of the human population, continue to suffer from iron deficiency. Iron supplementation programs have been advocated for infants and preschool children, largely because of concerns of possible adverse effects of iron deficiency on mental and motor development. Similar concerns were instrumental in establishing salt iodization programs. The questions that will be addressed in this chapter concern the extent to which a shortage of iodine and iron during fetal and infant development impairs mental development, and the extent to which this impairment can be redressed by increasing the intake of these micronutrients. First, the stages of brain development in the fetus and infant will be addressed, followed by an assessment of the timing of vulnerable periods when the brain of the fetus and infant is at high risk of exposure to an inadequate supply of iodine or iron. Where possible, the mechanisms involved will be discussed. Then, observational and intervention studies will be reviewed that have examined the effect of deficiencies of iodine or iron on mental development. Approximately half of the world’s population may be at risk of low zinc intake [3]. Given this high prevalence, inconclusive but mounting evidence that zinc deficiency during pregnancy may possibly impair the infant’s neurobehavioral development and immune function should also raise great concern [4–10]. However, because of space limitations, such effects and those of other micronutrients [11] will not be reviewed in the present report.

Malarial anemia is associated with a shift in iron distribution from functional to storage compartments. This suggests a relative deficit in erythropoietin production or action similar to that observed in other infections. Our study in Kenyan children with asymptomatic malaria aimed at investigating whether malaria causes increased erythropoiesis, and whether the erythropoietic response appeared appropriate for the degree of resulting anemia. Longitudinal and baseline data were used from a trial with a 2 x 2 factorial design, in which 328 anemic Kenyan children were randomly assigned to receive either iron or placebo, and sulfadoxinepyrimethamine or placebo. Erythropoiesis was evaluated by serum concentrations of erythropoietin and soluble transferrin receptor. Prospectively collected data showed that malarial infection resulted in decreased hemoglobin concentrations, and increased serum concentrations of erythropoietin and transferrin receptor. Conversely, disappearance of malarial antigenemia resulted in increased hemoglobin concentrations, and decreased concentrations of these serum indicators. Additionally, our baseline data showed that current or recent malarial infection is associated with increased serum concentrations of erythropoietin and transferrin receptor, and that these were as high as or perhaps even higher than values of children without malarial infection and without inflammation. Our findings indicate that in asymptomatic malaria, the erythropoietic response is adequate for the degree of anemia, and that inflammation probably plays no or only a minor role in the pathogenesis of the resulting anemia. Further research is needed to demonstrate the role of deficient erythropoietin production or action in the pathogenesis of the anemia of symptomatic malaria. ? 2002 by The American Society of Hematology.

Summary Background Iron supplementation is recommended for children at high risk of anaemia, but its benefits may not outweigh the associated risk of malaria in areas of seasonal transmission. We investigated the effect on haemoglobin concentrations of intermittent administration of iron supplements and sulfadoxine-pyrimethamine in symptom-free children under intense health surveillance. Methods In a trial of two by two factorial design, 328 anaemic Kenyan children were randomly assigned either iron or placebo and sulfadoxine-pyrimethamine or placebo (82 to each group). Primary outcomes were haemological indicators of iron status and inflammation at the end of the follow-up, and occurrence of malaria attacks. Morbidity surveillance consisted of medical examinations every 4 weeks, continuous passive case detection, and visits twice a week to community health-workers. Analyses were by intention to treat. Findings After 12 weeks, the groups assigned iron plus sulfadoxine-pyrimethamine, iron alone, or sulfadoxine-pyrimethamine alone had higher haemoglobin concentrations than the group assigned placebo (treatment effect adjusted for prognostic factors at baseline: 11·1 g/L [95% CI 7·5 to 14·7]; 10·7 g/L [7·1 to 14·3]; and 3·1 g/L [−0·5 to 6·7]). Administration of iron plus sulfadoxine-pyrimethamine also lowered the proportion with anaemia from 100% at baseline to 36% at 12 weeks, and of iron deficiency from 66% at baseline to 8% at 12 weeks. Survival analysis showed no evidence of substantially increased risk of malaria after iron supplementation. Interpretation Iron supplementation gives substantial health benefits, which may outweigh possible inherent risks caused by malaria. A larger study than ours is needed to assess benefits and risks of intermittent administration of sulfadoxine-pyrimethamine in reducing the incidence of malaria attacks in areas of seasonal malaria transmission.

Objective. Evidence from previous studies that malnourished children are protected against malaria is controversial. In individuals repeatedly exposed to malaria, immunity may develop first against severe disease, then against pyrogens, and last, against parasites. If this is true, this would suggest that reduced immune function that may exist in stunted children exacerbates the severity of malarial signs and symptoms, rather than the occurrence of parasitemia. On the other hand, several studies have suggested that malnourished children are protected to some degree against malaria. Our aim was to evaluate whether observational data support the hypothesis that nutritional inadequacies that cause stunting modify the associations between malaria and hematologic indicators such as hemoglobin concentration and serum concentrations of C-reactive protein and soluble transferrin receptor (sTfR). We showed earlier that increased serum concentrations of these receptors in asymptomatic malaria may be explained, at least in part, by increased erythropoiesis to compensate for malaria-induced hemolysis. Methodology. Community-based cluster survey among Kenyan children aged 2 to 36 months asymptomatic for malaria or anemia (n = 318). Results. When adjusted for age and wasting, the malaria-associated decrease in mean hemoglobin concentration was 8.5 g/L and 15.8 g/L in nonstunted and stunted children, respectively. The malaria-associated increase in geometric mean serum concentrations of sTfR was 1.1-fold and 1.8-fold in nonstunted and stunted children, respectively. The malaria-associated increase in geometric mean serum concentrations of C-reactive protein was 1.4-fold and 2.3-fold in nonstunted and stunted children, respectively. Thus, children with malaria and those who were stunted suffered from more severe anemia and had higher serum concentrations of C-reactive protein and sTfR than would be expected from the combined effect of the 2 working independently. Conclusions. Our results are consistent with the notion that the nutritional inadequacies causing stunting also impair host immunity, thus increasing the degree to which malaria is associated with decreased concentrations of hemoglobin, with increased inflammation, and with increased iron demand in developing erythroblasts. Increased intake of micronutrients may not only reduce stunting and nutritional anemia, but also reduce malaria-associated anemia.

Selective digestive decontamination (SDD) is the most extensively studied method for the prevention of infection in patients in intensive care units (ICUs). Despite 27 prospective randomized studies and six meta-analyses, routine use of SDD is still controversial. In this review, we summarize the available scientific information on effectiveness of SDD in ICU patients. The effects of SDD have been studied in different combinations of the concept, using different antibiotics. Comparison of the individual studies, therefore, is difficult. In most studies, SDD resulted in significant reductions in the number of diagnoses of ventilator-associated pneumonia. However, incidences of ventilator-associated pneumonia in control groups ranged from 5% to 85%. Moreover, these reductions in incidences of ventilator-associated pneumonia in individual studies were not associated with improved patient survival, reductions of duration of ventilation or ICU stay, or reductions in antibiotic use. The numbers of patients studied are too small to determine effects on patient survival. Although two meta-analyses suggested a 20% mortality reduction when using the full concept of SDD (topical and systemic prophylaxis) these results should be interpreted with caution. Formal cost-benefit analyses of SDD have not been performed. SDD is associated with the selection of microorganisms that are intrinsically resistant to the antibiotics used. However, the studies are too small and too short to investigate whether SDD will lead to development of antibiotic resistance. As long as the benefits of SDD (better patient survival, reduction in antibiotic use or improved cost-effectiveness) have not been firmly established, the routine use of SDD for mechanically ventilated patients is not advised.

Sunil Sazawal and colleagues in their large trial in Pemba Zanzibar found that zinc supplementation led to a less-than-expected reduction of mortality (7%; 95% CI -6 to 19). The study was designed with a 90% probability to detect a 20% reduction in mortality. It is not helpful that Sazawal and colleagues take this power into consideration when interpreting the results. First the results indicate that power calculations were based on assumptions that were not met during trial implementation. A study with an expected upper limit equal to a particular value will have only 50% probability of yielding an upper limit below that value. Thus under the conditions prevailing in the Pemba trial the probability of detecting a mortality reduction of 19% is only 50%. (excerpt)

The aims of this study were to estimate the proportion of asymptomatic Kenyan preschool children using anti-malarial drugs, to identify factors associated with chloroquine use, and to assess the validity of frequency of febrile episodes and drug use reported by mothers or carers. Of 318 children studied, 38% (95% confidence interval [CI] = 30-47%]) tested positive for chloroquine or sulfadoxine. Of chloroquine-positive children, 15% had concentrations exceeding the estimated minimum therapeutically effective values. Among those testing negative for sulfadoxine, chloroquine-positive children were more frequently parasitemic (odds ratio = 2.6, 95% CI = 1.3-5.2), and had lower mean hemoglobin concentrations (6.1 g/L, 95% CI = 2.1-10.1) than chloroquine-negative children. Mothers over-reported the frequency of malaria or fever episodes as usually defined in medical studies, and underreported anti-malarial drug use. We conclude that anti-malarials are frequently given for treatment of malaria or malaria-associated illness, rather than prophylactically or for symptoms unrelated to malaria. Questionnaire surveys cannot replace biochemical markers to obtain information on anti-malarial drug use.

Since the British doctor Ronald Ross received the 1902 Nobel Prize in medicine for his work on malaria, more people have died from the disease than all world wars combined. This is in spite of the fact that the French chemists Pierre Joseph Pelletier and Joseph Bienaimé Caventou made quinine available from as early as 1820. According to the World Health Organisation (WHO), there were about 219 million cases of malaria in 2010 and an estimated 660,000 deaths majority of which (80% of cases and 90% of deaths) were in Africa. Of almost two billion people who are anaemic globally, 41.8% are pregnant women. Iron supplements are used to prevent anaemia. There are concerns that iron given in high doses may increase malaria rates. Uncertainties regarding the safety of iron supplementation in malaria endemic regions were propelled by a randomized controlled trial that evaluated the effects of iron and folic acid supplementation in 32,155 children in Pemba, Tanzania. This study found that children who received iron and folic acid supplements were more likely to die or to need hospitalisation for an adverse event. At the same time, malaria is known to exacerbate anaemia; an almost inevitable consequence of malarial infection. As such, the safety of daily oral use of iron supplements by pregnant women, as a public health intervention is still not clearly established; at least not until publication of our main findings. This thesis assessed the effects of iron supplementation on safety indicators, and on iron status, in pregnant women and their neonates. Several preparatory activities were carried out, including a census of the population in the study area and a pilot study to check the operability of the study protocols. A main study was designed with the hypothesis that consumption of food products fortified with iron combined with intake of iron supplements especially in pregnancy, would be detrimental to the health of pregnant women and their neonates. The objectives of the study were: 1) to compare the presence of malarial infection in parturient women who received a combination of iron-fortified foods with iron supplements versus iron-fortified foods only; 2) to assess intervention effects on the maternal prevalence of iron deficiency anaemia at 1 month after delivery; 3) to assess intervention effects on neonatal iron stores at 1 month of age; 4) to assess the diagnostic utility of Zinc protoporphyrin (ZPP) in diagnosing iron deficiency in malaria endemic regions; 5) to identify baseline factors that are prognostic for the Non-Transferrin Bound Iron (NTBI) response to consumption of a single iron supplement; 6) to determine the factors that predict Plasmodium infection in pregnancy; 7) to identify factors associated with birth weight; 8) to develop a methodology to predict cases of low birth weight, using a single prognostic score that is based on prognostic variables collected at the second trimester of pregnancy; and 9) to develop methods for community-based flour fortification with iron. Most countries have enacted, or are in the process of enacting legislation for mandatory fortification of flour with iron. Thus pregnant women may receive iron from fortified foods and from universal iron supplementation programmes. This thesis provides answers to pertinent questions regarding the safety and efficacy of iron supplementation by comparing daily high-dose iron (i.e. iron-fortified foods plus iron supplements) versus low-dose iron (i.e. iron-fortified foods only) during pregnancy. The main outcome measure was the presence of maternal Plasmodium infection at birth, regardless of species. Chapter 1 is a detailed introduction of the background to the study and the design of the study. This thesis presents concrete evidence that iron supplementation to pregnant women in a highly malaria endemic region does not result in increased risk of malarial infection; percent difference (95%CI) = 0.0% (─9.3% to 9.3%). Programme implementers and governments in malaria endemic regions should not be held back by previous recommendations that cautioned against issuing iron supplements to pregnant women. In light of these findings, there is no need to first screen for malaria before giving iron supplements. Iron supplementation had major benefits for mothers and their neonates (chapter 2). The findings reported in this thesis showed a mean increase in birth weight of 143 g relative to the low-dose iron group. The effects of iron were influenced by the participants initial iron status. Correction of iron deficiency increased birth weight by 249 g, even though we cannot exclude the possibility that this may have increased malarial infection by 10%. There was no evidence that effects of iron on birth weight were influenced by intermittent preventive treatment against malaria. Iron supplementation also increased fetal growth by 0.27 SD, 95%CI: (0.04 to 0.50) probably as a result of gains in length and weight for gestation age. We also showed improved neonatal iron stores one month post-partum as indicated by a 17.1 % (95% CI: 2.0% to 34.3%) increase in plasma ferritin concentration in neonates of mothers who received high-dose iron compared to those who received low-dose iron. This provides more impetus to the need to offer iron supplements to pregnant women with the aim of boosting infant iron stores (chapter 2). ZPP was found to be of unreliable diagnostic utility when discriminating between pregnant women with and without iron deficiency in regions where chronic diseases are prevalent (chapter 3). The current conventional cut off points for whole blood ZPP e.g. >70 μmol/mol heme, can result in gross estimates of the prevalence of iron deficiency especially if the true prevalence is low. The appearance of non-transferrin bound iron (NTBI) in circulation after oral ingestion of iron supplements has been thought to aid the growth and multiplication of Plasmodium parasites thereby increasing malaria induced morbidity and mortality. We did not observe any increase in NTBI concentrations three hours after oral ingestion of 60 mg of ferrous fumarate (Chapter 4). We cannot exclude the possibility that iron supplementation leads to NTBI production when supplements are not consumed with food, because the lunch meal consumed by majority of our participants during the 3-hour waiting period probably contained natural compounds (phytates) that may have limited an NTBI response. In chapter 5 of this thesis, we aimed to develop a field friendly tool that can be used to predict asymptomatic Plasmodium infection. This was motivated by the fact that most point-of-care dipstick tests used to detect Plasmodium infection are not able to detect 100% of all the infection present yet asymptomatic infections are increasingly associated with adverse maternal and neonatal outcomes. Although many likely predictive factors were assessed individually or in combination with others, we did not succeed in developing a reliable tool that is easy to apply in resource-poor malaria endemic settings. In Chapter 6, we aimed to identify factors associated with birth weight and to develop a methodology to predict cases of low birth weight using a single prognostic score that is based on prognostic variables collected at the second trimester of pregnancy. Factors that were found to be independently associated with reduced birth weight were being never married, inflammation, being a girl, and iron deficiency. Being overweight was associated with increased birth weight. The results indicate that we can use variables collected rapidly and at relatively low cost and ease to identify with fair accuracy women in the second trimester of pregnancy who are at high risk of giving birth to a neonate with low birth weight. The various aspects of the work presented in this thesis including the implications for policy makers are discussed in chapter 7. For policy makers, the findings of this thesis are a welcome relief. The findings therein eliminate all doubt that has hitherto been associated with antenatal iron supplementation in malaria endemic areas. Most countries already have iron supplementation policies that are well aligned to the World Health Organisation policies. Efforts to widen the coverage of antenatal iron supplementation especially in malaria endemic regions should be urgently scaled up. However, the evidence provided in this thesis is only applicable to pregnant women and cannot be extrapolated to children in malaria endemic regions. For this population, the current WHO policy must be used thus before iron supplementation, children must first be screened for malaria. Although this thesis provides answers to key scientific questions that have hitherto baffled the scientific community, there are still research questions that can be clarified further. The effects of a high iron dose in pregnancy (as per national and international guidelines, the daily supplementation dose for pregnant women should be doubled to 120 mg iron if they are anaemic or if 6 months duration cannot be achieved in pregnancy (Chapter 2)) on maternal and neonatal outcomes need to be elucidated. Further research is needed in order to describe fully, the NTBI response to consumption different types and amounts of oral iron supplements. There is urgent need for diagnostic tools that can be used in resource-poor settings to diagnose asymptomatic infections. Further research in children is needed to provide evidence of the safety and efficacy of iron supplementation in malaria endemic regions and to assess the diagnostic performance of zinc protoporphyrin in children. In addition, since our studies suggest that screening based on Hb concentration as now practiced in many countries, is inaccurate in discriminating between women at high and low risk of delivering neonates with low birth weight, further studies are needed to identify appropriate markers and cut-off points that are suited to this purpose. In conclusion, this thesis has shown that there is no evidence that antenatal iron supplementation increases Plasmodium infection. Antenatal iron supplementation leads to large improvements in birth weight, fetal growth and infant iron stores, with potentially immense benefits for infant survival and health that should outweigh any possible concerns about risks of malaria. Epidemiological calculations indicate that if our results are applied to all women in developing countries in order to eliminate iron deficiency, we could avoid 3 million births with low birth weight annually and save the lives of more than half a million neonates. Scaling up universal iron supplementation in pregnancy in developing countries will generate major public health gains.

This thesis aimed at investigating the role of genetic and nutritional factors that affect the immune response to malaria in Tanzanian children. The introductory chapter (Chapter 1) reviews the importance of nutritional deficiencies, particularly of zinc, and presents the hypothesis that such deficiencies lead to impaired immunity and contribute to the burden of malaria. The chapter also describes current efforts to prevent malaria through intermittent preventive treatment, both in infants (IPTi) and pregnant women (IPTp). Sulfadoxinepyrimethamine is still used for first-line treatment of uncomplicated malaria, or, in many countries, to prevent malaria and anaemia in pregnancy. In malaria endemic areas, development of resistance to previously valuable antimalarial drugs has been continuously reported for decades. Thus our initial longitudinal study aimed at measuring the prevalence of resistance-associated mutations on dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) genes (dhfr and dhps) that confer parasite resistance to sulphadoxinepyrimethamine (SP) that was used as an interim antimalarial drug after chloroquine resistance. Although SP resistance-associated point mutations were highly prevalent, we observed an adequate parasite response to SP (Chapter 2). We speculated that the impact of the dhfr and dhps mutations on SP resistance may be dependent at least in part on the protective immunity that has developed in response to frequent exposure to infection and may be weighed down by host immunity in endemic areas and thus impacts in the continued use of the drug for treatment of malaria. The impact of other drugs with similar mechanisms of action used as antibiotics in selecting mutations responsible for SP resistance needs therefore to be studied for their modulating activity of the immune response. These findings underscore the relevance to further study the crucial involvement of the immune system in the development of protection against malaria but also affecting the efficacy of treatment modalities of malaria in various African conditions. In the subsequent cross-sectional studies, we assessed the effect of deficiencies of zinc and magnesium as well as iron deficiency anaemia on malaria-specific cytokine responses indicative of innate immunity to Plasmodium falciparum (Chapter 3). In this study, we used Plasmodium falciparum-parasitised red blood cells (pRBCs) as antigens for in vitro stimulation of peripheral blood mononuclear cells (PBMCs). Cytokines were measured in the supernatant of cultured PBMCs after 24 hours of stimulation. Zinc deficiency was associated with a marked increase in monocyte-derived TNF-α concentration in children with malarial infection but not in their uninfected peers. In children with malarial infection, iron deficiency anaemia was associated with elevated concentrations of TNF-α, whereas magnesium deficiency in children without malaria seemed to be associated with increased concentrations of IL-10. Our findings reflected plasticity in cytokine profiles of monocytes reacting to malaria infection under conditions of different nutrient deficiencies. Following the observation of the variable impact of micronutrients on innate cytokines, we evaluated the profile of both type I and type II cytokines and whether they were influenced by nutritional and malaria status (Chapter 4). The cytokine measurements were performed at day 7 of stimulation anticipating that this timing was optimal for measuring effects on these cytokines mainly derived from activated T-cells. The results indicated a variable influence of nutrient deficiencies on increased cytokine response with zinc deficiency and iron deficiency anemia having greater impact on type I and magnesium deficiency on type II cytokines. The subsequent study evaluated the plasma levels of naturally acquired antimalarial antibodies of variousIgG subclasses plus the total IgG and IgM levels and whether they were associated with zinc deficiency based on preceding chapters (Chapter 5). The results indicated a high variability in antibody levels with zinc deficiency, varying with age of the affected child. IgG3 appeared to be predominant across all age subgroups within < 5 yrs aged children providing clues that IgG3 might confer immune protection to malaria under conditions of zinc deficiency. Chapter 6 explored the association between CD36 deficiency, P. falciparum in vitro adherence on purified CD36 and anemia in children. CD36 is a receptor that occurs on the surface of activated immune cells and vascular endothelial cells and participates in phagocytosis and lipid metabolism. We hypothesized that it could play a fundamental role in cytoadherence of erythrocytes that are parasitized by Plasmodium. Our results showed that CD36 deficiency was associated with protection against the development of malarial anemia in children and that it may be mediated through reduced cytoadherence of infected red blood cells to vascular endothelium. These studies demonstrate that despite antimalarial drug resistance, there is a potential for optimizing the immunological protective capacity in the population to confer parasite clearance that can be variably influenced by micronutrient status. Improving nutritional status in this population could be rewarding not only to increase protection to malaria but possibly also to other infections.

Food fortification is an effective strategy for reaching populations with micronutrient deficiencies. Fortification with iron presents a major challenge because of the presence of phytates and other iron absorption inhibitors in diets of poor people. Addition of iron does not necessarily mean that it is absorbed. Because of its low cost and its relative stability in food vehicles, electrolytic iron has been the fortificant of choice in many national programmes, despite its low bioavailability compared to fortificants such as ferrous salts. NaFeEDTA may be a more effective iron fortificant in high-phytate foods. Concerns about its cost and safety, however, have delayed its application in fortification programmes. This thesis is based on a 5-month randomised placebo-controlled trial conducted among school children (n = 516) aged 3-8 years in Kenya in May-November 2005. It aimed to measure the benefits of fortification with NaFeEDTA or electrolytic iron, and to assess the safety of using NaFeEDTA as an iron fortificant. The specific objectives were to assess a) the efficacy of fortifying whole maize flour with NaFeEDTA (28 mg iron/kg flour or 56 mg/kg) or electrolytic iron (56 mg/kg); b) the effect of the intervention on cognitive and motor function; c) response to the intervention of individuals with α+-thalassaemia genotype relative to their counterparts with a normal genotype; d) and the effect of NaFeEDTA on the status of zinc, calcium, copper, magnesium and manganese. Fortification with NaFeEDTA at high levels (56 mg iron per kg flour), or low levels (28 mg/kg) reduced the prevalence of iron deficiency anaemia by 89% (95% CI 49% to 97%) and 48% (-20% to 77%), respectively. High-dose fortification with NaFeEDTA led to larger gains in iron status than low-dose level, and was more efficacious in children with iron deficiency at baseline. By contrast, electrolytic iron did not improve iron status. There was no evidence that the iron intervention improved either cognitive or motor function of these children; or that children with the α+-thalassaemia genotype responded differently to the iron intervention than their peers with a normal genotype. There was also no evidence that NaFeEDTA adversely affected the status of the nutritionally important mineral elements assessed. The thesis concludes that in high-phytate flours, NaFeEDTA is more suitable than electrolytic iron for supplementation of iron in the diet. Governments should act and implement national programmes to fortify industrially processed flour, whereby NaFeEDTA should be considered the preferred fortificant in high-phytate food vehicles.

In developing countries, adolescent girls often have anemia and micronutrient deficiencies. The objective of this thesis was to investigate the role of riboflavin or vitamin A as determinant of anemia and iron deficiency in Indonesian adolescent girls.