Riboflavin-iron interactions with particular emphasis on the gastrointestinal tract

Hutton Z, Fattore G, Sabatier M, Detzel P. Reducing the burden of iron deficiency anemia in Cote D'Ivoire through fortification

BACKGROUND

Iron deficiency anemia (IDA) is highly prevalent in the Cote d'Ivoire and has severe health and economic consequences. In this paper, we apply a health economic model to quantify the burden of IDA, and the contribution of nationwide mandatory iron fortification of wheat flour and voluntary iron fortification of condiments to the reduction of this burden.

METHODS

The analysis for the population from 6 months to 64 years builds on published reviews and publicly available datasets and is stratified by age-groups and socioeconomic strata using comparative risk assessment model.

RESULTS

Without the impact of these fortification strategies, the annual burden of IDA is estimated at 242,100 disability adjusted life years (DALYs) and 978.1 million USD. Wheat flour and condiment fortification contributed to a reduction of the IDA burden by approximately 5% each.

CONCLUSION

In places with high prevalence of malaria and other infectious diseases, such as the Côte D'Ivoire, food fortification as a nutritional intervention should be accompanied with infectious disease prevention and control. The findings of this study provide additional input for policy makers about the magnitude of the impact and can support the conception of future fortification strategies.

Riboflavin status, MTHFR genotype and blood pressure: current evidence and implications for personalised nutrition

Clinical deficiency of the B-vitamin riboflavin (vitamin B2) is largely confined to developing countries; however accumulating evidence indicates that suboptimal riboflavin status is a widespread problem across the developed world. Few international data are available on riboflavin status as measured by the functional biomarker, erythrocyte glutathione reductase activation coefficient, considered to be the gold standard index. One important role of riboflavin in the form of flavin dinucleotide is as a co-factor for the folate-metabolising enzyme methylenetetrahydrofolate reductase (MTHFR). Homozygosity for the common C677T polymorphism in MTHFR, affecting over 10 % of the UK and Irish populations and up to 32 % of other populations worldwide, has been associated with an increased risk of CVD, and more recently with hypertension. This review will explore available studies reporting riboflavin status worldwide, the interaction of riboflavin with the MTHFR C677T polymorphism and the potential role of riboflavin in personalised nutrition. Evidence is accumulating for a novel role of riboflavin as an important modulator of blood pressure (BP) specifically in individuals with the MTHFR 677TT genotype, with results from a number of recent randomised controlled trials demonstrating that riboflavin supplementation can significantly reduce systolic BP by 5-13 mmHg in these genetically at risk adults. Studies are however required to investigate the BP-lowering effect of riboflavin in different populations and in response to doses higher than 1·6 mg/d. Furthermore, work focusing on the translation of this research to health professionals and patients is also required.

Suspected outbreak of riboflavin deficiency among populations reliant on food assistance: a case study of drought-stricken Karamoja, Uganda, 2009-2010

BACKGROUND

In 2009, a humanitarian response was launched to address a food security and livelihoods crisis in Karamoja, Uganda. During a polio immunization campaign in mid-August 2009, health workers in Nakapiripit District reported a concern about an increase in mouth sores, or angular stomatitis (AS) and gum ulcerations, among children in one village, and an investigation was launched.

OBJECTIVE

This article describes the investigation, lessons learned, and provides guidance for monitoring micronutrient deficiencies among populations receiving food assistance.

DESIGN

An investigation into a suspected outbreak of riboflavin (vitamin B2) deficiency was initiated, including a rapid assessment, mass screening, a convenience sample collection of blood specimens (n = 58 symptomatic cases and n = 18 asymptomatic individuals), and analysis of the general food ration (70% ration).

RESULTS

Findings showed signs of AS in only 399 (0.2%) of 179,172 screened individuals, including adults and children. Biochemical analysis confirmed riboflavin deficiency in 84.5% of specimens from symptomatic individuals and 94.4% of specimens from asymptomatic individuals. Ration distribution data showed that 55% of distributions provided less than half the riboflavin RDA.

CONCLUSION

Evidence was insufficient to confirm an actual outbreak of riboflavin deficiency, though the present investigation adds further documentation that micronutrient deficiencies continue to persist among populations in emergency settings. This article describes challenges, lessons learned, and guidance for monitoring micronutrient deficiencies among food assistance recipients, including: ongoing nutrition monitoring and surveillance; training and sensitization about micronutrient deficiencies, sensitization of the population about locally-available food, and identifying ways to improve micronutrient interventions.

Vitamin requirements for term infants: considerations for infant formulae

OBJECTIVE

To provide the informed health professional with an up to date evaluation of the current thinking regarding requirements for vitamins in infant feeds. ESTABLISHING CRITERIA FOR ADEQUACY: Vitamin adequacy in the neonate is currently defined in terms of circulating levels of a vitamin or of the activity of a vitamin dependent enzyme in the erythrocytes. Although these measurements have their value there is a need to develop biochemical, physiological or clinical markers of well defined specific function. For some vitamins there is a risk of deleterious effects of very high intakes: risk of toxicity needs to be taken into consideration when making recommendations for inclusion in infant formulae. BREAST MILK AS THE 'GOLD STANDARD': Breast milk concentrations of vitamins have been used as the criteria of adequate intake by neonates. This may not always be justified. Greater consideration needs to be given to differences in bioavailability of vitamins from breast milk compared with formula feeds, of the influence of season, and of stage of lactation, on the stated composition.

EXPERIMENTAL APPROACHES

Animal studies have provided limited information regarding effects of different levels of intakes on current status indices in the neonatal period. There are few reports of randomized controlled studies into the effects of different levels of vitamins and these rely heavily on biochemical criteria of adequacy.

RECENT DEVELOPMENTS

The inclusion of beta-carotene into formula feeds for premature babies is an issue of current interest. What is the justification for this? Are there potential benefits for the term infant? Riboflavin deficiency in the period around weaning may affect the normal structural and functional development of the gastrointestinal tract; some of these effects may be permanent. RESEARCH TO BE DONE: A greater understanding of the absorption and metabolism of vitamins during infancy is required in order to help establish dietary requirements. The relative bioavailability of vitamins in human milk and formulae needs to be investigated. Criteria for vitamin adequacy should be extended to include measures of function. Information regarding the conversion factor from tryptophan to niacin in infancy would allow us to set niacin requirements with greater confidence. There is a particular lack of information about concentrations of biotin and pantothenic acid in breast milk and the relative biochemical status of infants receiving breast milk and formulae. Benefits of including beta-carotene into infant formulae need to be evaluated. The role of individual micronutrients in the structural and functional development of the gastrointestinal tract should be explored.

Efficacy and safety of twice-weekly administration of three RDAs of iron and folic acid with and without complement of 14 essential micronutrients at one or two RDAs: a placebo-controlled intervention trial in anemic Cambodian infants 6 to 24 months of age

OBJECTIVE

To determine the differential efficacy and safety of twice-weekly administration of 3 RDAs of iron and folic acid, with and without a complement of 2 RDAs of 11, and 1 RDA of 3 additional essential micronutrients as compared to a placebo control (PlbCON) given as foodLETs.

SUBJECTS/METHODS

A total of 250 children aged 6-24 months were enrolled after recruitment by village health workers; 19 of them dropped out during the trial. Children were assigned to one of three treatment arms and followed for 20.5 weeks; 41 supervised twice-weekly dosings of 30 mg of iron plus folic acid, either with or without accompanying micronutrients or placebo were given as foodLETs, a tool for ready-to-eat fortification in infant food. Initial and final measurements of anthropometry and blood biomarkers for hematological, iron stores and inflammatory status, as well as for abnormal hemoglobin (Hb), were obtained. Symptoms of listlessness, vomiting, watery stools and acute respiratory infections were monitored weekly.

RESULTS

Iron-containing supplements increased Hb concentrations significantly (P<0.0001) and virtually eradicated any IDA, as compared to no change in hematological status in the PlbCON group (P=0.011). Iron stores, as reflected by ferritin, increased significantly with iron-containing treatments (P<0.0001). Responses were as effective in individuals with HbE as in those with exclusively HbA phenotypes. Watery stools (P=0.002) and listlessness (P=0.001) were significantly more frequent in those receiving iron and folic acid alone than in the PlbCON group. In contrast, acute respiratory infections (P=0.014) and listlessness (P=0.001) were significantly less frequent in those receiving the multiple micronutrient formulation than in the PlbCON group.

CONCLUSIONS

Supplementation of micronutrients along with iron and folic acid mitigates the excess morbidity of iron-folate alone, without reducing its efficacy in correcting anemia and building iron stores. FoodLETs are a suitable vehicle to provide micronutrient supplementation to infants.

Riboflavin biosynthesis is associated with assimilatory ferric reduction and iron acquisition by Campylobacter jejuni

One of the pathways involved in the acquisition of the essential metal iron by bacteria involves the reduction of insoluble Fe(3+) to soluble Fe(2+), followed by transport of Fe(2+) to the cytoplasm. Flavins have been implicated as electron donors in this poorly understood process. Ferrous iron uptake is essential for intestinal colonization by the important pathogen Campylobacter jejuni and may be of particular importance under low-oxygen conditions. In this study, the links among riboflavin biosynthesis, ferric reduction, and iron acquisition in C. jejuni NCTC11168 have been investigated. A riboflavin auxotroph was generated by inactivation of the ribB riboflavin biosynthesis gene (Cj0572), and the resulting isogenic ribB mutant only grew in the presence of exogenous riboflavin or the riboflavin precursor diacetyl but not in the presence of the downstream products flavin adenine dinucleotide and flavin mononucleotide. Riboflavin uptake was unaffected in the ribB mutant under iron-limited conditions but was lower in both the wild-type strain and the ribB mutant under iron-replete conditions. Mutation of the fur gene, which encodes an iron uptake regulator of C. jejuni, resulted in an increase in riboflavin uptake which was independent of the iron content of the medium, suggesting a role for Fur in the regulation of the as-yet-unknown riboflavin transport system. Finally, ferric reduction activity was independent of iron availability in the growth medium but was lowered in the ribB mutant compared to the wild-type strain and, conversely, increased in the fur mutant. Taken together, the findings confirm close relationships among iron acquisition, riboflavin production, and riboflavin uptake in C. jejuni.

Mild riboflavin deficiency is highly prevalent in school-age children but does not increase risk for anaemia in Côte d'Ivoire

There are few data on the prevalence of riboflavin deficiency in sub-Saharan Africa, and it remains unclear whether riboflavin status influences the risk for anaemia. The aims of this study were to: (1) measure the prevalence of riboflavin deficiency in children in south-central Côte d'Ivoire; (2) estimate the riboflavin content of the local diet; and (3) determine if riboflavin deficiency predicts anaemia and/or iron deficiency. In 5- to 15-year-old children (n281), height, weight, haemoglobin (Hb), whole blood zinc protoporphyrin (ZPP), erythrocyte glutathione reductase activity coefficient (EGRAC), serum retinol, C-reactive protein (CRP) and prevalence ofPlasmodiumspp. (asymptomatic malaria) andSchistosoma haematobium(bilharziosis) infections were measured. Three-day weighed food records were kept in twenty-four households. Prevalence of anaemia in the sample was 52 %; 59 % were iron-deficient based on an elevated ZPP concentration, and 36 % suffered from iron deficiency anaemia.Plasmodiumparasitaemia was found in 49 % of the children. Nineteen percent of the children were infected withS. haematobium. Median riboflavin intake in 5- to 15-year-old children from the food records was 0·42 mg/d, ~47 % of the estimated average requirement for this age group. Prevalence of riboflavin deficiency was 65 %, as defined by an EGRAC value >1·2. Age, elevated CRP and iron deficiency were significant predictors of Hb. Riboflavin-deficient children free of malaria were more likely to be iron deficient (odds ratio; 3·07; 95 % CI 1·12, 8·41). In conclusion, nearly two-thirds of school-age children in south-central Côte d'Ivoire are mildly riboflavin deficient. Riboflavin deficiency did not predict Hb and/or anaemia, but did predict iron deficiency among children free of malaria.

Effect of low-dosage vitamin A and riboflavin on iron-folate supplementation in anaemic pregnant women

A double-blind, placebo, controlled trial was conducted in Banyudono subdistrict, Boyolali regency, Central Java province, Indonesia. The aim of the study was to determine whether adding low-dosage vitamin A and riboflavin can enhance the effect of iron-folate supplementation in anaemic pregnant women. From July to November 2000, 202 pregnant women were screened for anaemia (haemoglobin < 11.0 g/dL). One hundred and three pregnant women (51%) were found to be anaemic and were then allocated alternately into four groups. Over a period of 60 days, group IF (n = 29) received iron-folate tablets (200 mg FeSO4 and 250 microg folic acid) + 5 mg glucose: group IFR (n = 22) received iron-folate tablets + 5 mg riboflavin; group IFA (n = 29) received iron-folate tablets + 2.75 mg retinyl palmitate (equal to 5000 IU vitamin A); and group IFRA (n = 23) received iron-folate tablets + 5 mg riboflavin + 2.75 mg retinyl palmitate. At the end of the study 19 pregnant women (18.4%) were excluded from the analysis because of various reasons. Statistical analysis was based on 84 women (81.5%): group IF, n = 25; group IFR, n = 22; group IFA, n = 18; and group IFRA, n = 19. Haemoglobin measurements were carried out using the Technicon H1* (cyanmethaemoglobin method). All groups showed a significant increase in haemoglobin concentration (P < 0.05), except group IFA (P > 0.05), with the highest increment being in group FR. Multiple comparisons only showed significant differences between group IFR and group IFA (P < 0.05). It can be concluded that iron-folate supplementation can increase haemoglobin concentrations in anaemic pregnant women. Adding riboflavin tends to enhance the effect of iron-folate supplementation, but this is not the case with adding vitamin A.

Angular stomatitis and riboflavin status among adolescent Bhutanese refugees living in southeastern Nepal

BACKGROUND

Between 1990 and 1993, fear of ethnic persecution led 83,000 ethnic Nepalese to flee from Bhutan to refugee camps in Nepal, where they remained at the time of this study. Reported cases of angular stomatitis (AS), ie, thinning or fissuring at the mouth angles, increased 6-fold from December 1998 to March 1999, from 5.5 to 35.6 cases per 1000 per month. This increase came after the removal of a fortified cereal from rations.

OBJECTIVES

The main objectives were to assess the prevalence of AS and of low concentrations of riboflavin, folate, vitamin B-12, and iron by using biochemical measures; to determine whether riboflavin status was associated with AS; and to assess the potential of AS as a screening measure for low riboflavin concentrations.

DESIGN

In October 1999, we performed a survey among a random sample of 463 adolescent refugees in which we conducted interviews and physical examinations and obtained blood specimens for riboflavin assessment. Riboflavin status was assessed with the erythrocyte glutathione reductase (EC 1.6.4.2) activity coefficient. After we excluded those adolescents who had taken vitamins during the past month, 369 were eligible for analyses.

RESULTS

AS was common (26.8%; 95% CI: 22.3, 31.3), the prevalence of low riboflavin concentrations was high (85.8%; 80.7, 90.9), and riboflavin status was associated with AS. Adolescents with AS had significantly lower riboflavin concentrations than did adolescents without AS (P = 0.02). The adjusted odds ratio for AS and low riboflavin concentrations was 5.1 (1.55, 16.5).

CONCLUSION

Globally, riboflavin deficiency is rare. Its emergence in food-dependent populations can be a harbinger of other B-vitamin deficiencies.

The role of vitamins in the prevention and control of anaemia

OBJECTIVE

While iron deficiency is regarded as the major cause of nutritional anaemia, changes in vitamins A, B12, C and E, folic acid and riboflavin status have also been linked to its development and control. This paper provides a systematic review of vitamin supplementation trials relating to the control of nutritional anaemia.

METHODS

A MEDLINE search was used to find reports of vitamin supplementation trials that reported changes in anaemia or iron status.

RESULTS

Vitamin A can improve haematological indicators and enhance the efficacy of iron supplementation. Both folate and vitamin B12 can cure and prevent megaloblastic anaemia. Riboflavin enhances the haematological response to iron, and its deficiency may account for a significant proportion of anaemia in many populations. Vitamin C enhances the absorption of dietary iron, although population-based data showing its efficacy in reducing anaemia or iron deficiency are lacking. Vitamin E supplementation given to preterm infants has not reduced the severity of the anaemia of prematurity. Vitamin B6 effectively treats sideroblastic anaemia. Multivitamin supplementation may raise haemoglobin (Hb) concentration, but few studies have isolated the effect of multivitamins from iron on haematological status.

CONCLUSIONS

In general, the public health impact of vitamin supplementation in controlling anaemia is not clear. Neither are the complex interactions involving multiple vitamins in haematopoiesis sufficiently understood to explain the observed variability in haematological responses to vitamins by age, population, vitamin mixture and dosages. Further research is needed to understand the roles of individual and combined vitamin deficiencies on anaemia to design appropriate micronutrient interventions to prevent anaemia.

Current knowledge concerning optimum nutritional status of riboflavin, niacin and pyridoxine

The term 'optimum nutrition' has evolved from a perceived need to base recommendations for nutrient intakes firmly in the context of function. It follows that 'optimum nutritional status' for individual nutrients should be defined in terms of biochemical or physiological markers having some functional value but also showing an appropriate relationship to nutrient intake. The present short review considers the current position regarding such markers for riboflavin, pyridoxine and niacin. It is concluded that whilst there are several biochemical measures which respond to changes in intake of each of these vitamins, no single measure is wholly satisfactory as a marker of optimum status.