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Zhong Y, Shen L, Ye X, Zhou D, He Y, Li Y, Ding Y, Zhu W, Ding J, Zhang H. Neurotoxic Anatoxin-a Can Also Exert Immunotoxicity by the Induction of Apoptosis on Carassius auratus Lymphocytes in vitro When Exposed to Environmentally Relevant Concentrations. Front Physiol 2020; 11:316. [PMID: 32351401 PMCID: PMC7174720 DOI: 10.3389/fphys.2020.00316] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 03/20/2020] [Indexed: 12/17/2022] Open
Abstract
Hazardous anatoxin-a (ANTX-a) is produced by freshwater algal blooms worldwide, which greatly increases the risk of consumer exposure. Although ANTX-a shows widespread neurotoxicity in aquatic animals, little is known about its mechanism of action and biotransformation in biological systems, especially in immunobiological models. In this study, transmission electron microscopy results showed that ANTX-a can destroy lymphocytes of Carassius auratus in vitro by inducing cytoplasmic concentration, vacuolation, and swollen mitochondria. DNA fragmentations clearly showed a ladder pattern in agarose gel electrophoresis, which demonstrated that the apoptosis of fish lymphocytes was caused by exposure to ANTX-a. Flow cytometry results showed that the apoptotic percentage of fish lymphocytes exposed to 0.01, 0.1, 1, and 10 mg/L of ANTX-a for 12 h reached 18.89, 22.89, 39.23, and 35.58%, respectively. ANTX-a exposure induced a significant increase in reactive oxygen species (ROS) and malonaldehyde (MDA) in lymphocytes. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), and the glutathione (GSH) content of the 0.01 mg/L ANTX-a-treated group decreased significantly by about 41, 46, 67, and 54% compared with that of the control group (p < 0.01), respectively. Although these observations were dose-dependent, these results suggested that ANTX-a can induce lymphocyte apoptosis via intracellular oxidative stress and destroy the antioxidant system after a short exposure time of only 12 h. Besides neurotoxicity, ANTX-a may also be toxic to the immune system of fish, even when the fish are exposed to environmentally relevant concentrations, which clearly demonstrated that the potential health risks induced by ANTX-a in aquatic organisms requires attention.
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Affiliation(s)
- Yuchi Zhong
- School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Lilai Shen
- School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Xueping Ye
- Zhejiang Institute of Freshwater Fisheries, Huzhou, China
| | - Dongren Zhou
- Zhejiang Institute of Freshwater Fisheries, Huzhou, China
| | - Yunyi He
- School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Yan Li
- School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Ying Ding
- School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Weiqin Zhu
- School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Jiafeng Ding
- School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Hangjun Zhang
- School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
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Restrepo-Gallego M, Díaz LE. Influence of Dietary Vitamin A and Iron Deficiency on Hematologic Parameters and Body Weight of Young Male Wistar Rats. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE 2020; 59:17-23. [PMID: 31826798 DOI: 10.30802/aalas-jaalas-19-000020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Micronutrient deficiency is one of the most prominent public health concerns; in particular, vitamin A and iron are determinants of appropriate development, and vitamin A influences iron homeostasis and metabolism. Here we compared the effects of diets that were sufficient and insufficient in vitamin A and iron on the hematologic parameters and body weight of rats. Male Wistar rats were randomly divided into 5 dietary groups (n = 7 per group): adequate in iron and vitamin A (control); adequate in iron but low in vitamin A (FesvAi); adequate in iron but lacking vitamin A (FesvAd); low in iron but adequate in vitamin A (FeivAs); and low in both iron and vitamin A (FeivAi). After 6 wk, rats showed significant differences in serum iron relative to the control diet (control, 256 ± 44 μg/dL; FesvAi, 220± 16 μg/dL; FesvAd, 181 ± 15 μg/dL; FeivAs, 131 ± 44 μg/dL; FeivAi, 75 ± 19 μg/dL). Rats on iron-deficient diets showed reduced Hgb values relative to the control diet (control, 15.9 ± 0.7 g/dL; FeivAs, 13.2 ± 1.6 g/dL; FeivAi, 12.9 ± 1.0 g/dL), MCV (control: 57 ± 10 fL; FeivAs, 48 ± 10 fL; FeivAi, 44 ± 3 fL), and Hct (control, 53% ± 2%; FeivAs, 44% ± 5%; FeivAi, 42% ± 8%). All of the experimental dietary groups showed significant differences in reticulocyte count when compared with the control group (control, 2.7% ± 2.2%; FesvAd, 0.6% ± 0.2%; FesvAi, 0.3% ± 0.1%; FeivAs, 1.2% ± 0.2%; FeivAi, 0.6% ± 0.5%). The mean difference in body weight for the experimental groups, relative to the control group, was 30 ± 10 g. These results suggested that, in young male Wistar rats, both iron and vitamin A are essential to cause increases in body weight and various hematologic parameters.
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Lynch S, Pfeiffer CM, Georgieff MK, Brittenham G, Fairweather-Tait S, Hurrell RF, McArdle HJ, Raiten DJ. Biomarkers of Nutrition for Development (BOND)-Iron Review. J Nutr 2018; 148:1001S-1067S. [PMID: 29878148 PMCID: PMC6297556 DOI: 10.1093/jn/nxx036] [Citation(s) in RCA: 172] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/27/2017] [Accepted: 11/07/2017] [Indexed: 12/20/2022] Open
Abstract
This is the fifth in the series of reviews developed as part of the Biomarkers of Nutrition for Development (BOND) program. The BOND Iron Expert Panel (I-EP) reviewed the extant knowledge regarding iron biology, public health implications, and the relative usefulness of currently available biomarkers of iron status from deficiency to overload. Approaches to assessing intake, including bioavailability, are also covered. The report also covers technical and laboratory considerations for the use of available biomarkers of iron status, and concludes with a description of research priorities along with a brief discussion of new biomarkers with potential for use across the spectrum of activities related to the study of iron in human health.The I-EP concluded that current iron biomarkers are reliable for accurately assessing many aspects of iron nutrition. However, a clear distinction is made between the relative strengths of biomarkers to assess hematological consequences of iron deficiency versus other putative functional outcomes, particularly the relationship between maternal and fetal iron status during pregnancy, birth outcomes, and infant cognitive, motor and emotional development. The I-EP also highlighted the importance of considering the confounding effects of inflammation and infection on the interpretation of iron biomarker results, as well as the impact of life stage. Finally, alternative approaches to the evaluation of the risk for nutritional iron overload at the population level are presented, because the currently designated upper limits for the biomarker generally employed (serum ferritin) may not differentiate between true iron overload and the effects of subclinical inflammation.
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Affiliation(s)
| | - Christine M Pfeiffer
- National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA
| | - Michael K Georgieff
- Division of Neonatology, Department of Pediatrics, University of Minnesota School of Medicine, Minneapolis, MN
| | - Gary Brittenham
- Division of Pediatric Hematology, Oncology and Stem Cell Transplant, Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, NY
| | - Susan Fairweather-Tait
- Department of Nutrition, Norwich Medical School, Norwich Research Park, University of East Anglia, Norwich NR4 7JT, UK
| | - Richard F Hurrell
- Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Harry J McArdle
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen AB21 9SB, UK
| | - Daniel J Raiten
- Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH)
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Abstract
Iron-fortification programs are efficacious and effective provided recent guidelines are followed: the iron compound is carefully chosen and its level in the food is based on target population requirements, the amount lacking in the diet, and the iron bioavailability of the diet and the compound. For monitoring, serum ferritin and transferrin receptor should be included in addition to hemoglobin. Thus, recent studies of provision of iron-fortified salt to children in Morocco, rice to children in India, wheat flour to women in Thailand, and fish sauce in Vietnam have demonstrated efficacy and effectiveness. All were in nonmalarious areas, and intestinal parasites were uncommon except in India, where the children were dewormed. C-reactive protein was used to eliminate high ferritin values due to infection. An efficacy study of iron-fortified salt in dewormed school-aged children in Côte d'Ivoire, where the prevalence of malaria parasitemia was 55%, found no change in hemoglobin after 6 months, but serum ferritin increased and transferrin receptor decreased significantly, and the increase in body iron and estimated iron absorbed compared favorably with the results of a study of similar design in Morocco, where the prevalence of iron-deficiency anemia decreased from 30% to 5% after 10 months. Hence, iron-fortification programs in malarious areas may not decrease anemia prevalence but will improve iron status and, presumably, iron-dependent health outcomes. Eight studies in nonmalarious areas, all but one in infants receiving iron-fortified formula, have found no evidence of increase in infections and some evidence of a decrease in respiratory infection. There have been no studies in malarious areas.
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Affiliation(s)
- Richard F Hurrell
- ETH Zurich, Institute of Food Science and Nutrition, Zurich, Switzerland.
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Righetti AA, Koua AYG, Adiossan LG, Glinz D, Hurrell RF, N'goran EK, Niamké S, Wegmüller R, Utzinger J. Etiology of anemia among infants, school-aged children, and young non-pregnant women in different settings of South-Central Cote d'Ivoire. Am J Trop Med Hyg 2012; 87:425-34. [PMID: 22848097 DOI: 10.4269/ajtmh.2012.11-0788] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Anemia affects one-quarter of the world's population, but its etiology remains poorly understood. We determined the prevalence of anemia and studied underlying risk factors in infants (6-23 months), young school-aged children (6-8 years), and young non-pregnant women (15-25 years) in south-central Côte d'Ivoire. Blood, stool, and urine samples were subjected to standardized, quality-controlled methods. We found high prevalence of anemia, malaria, inflammation, and deficiencies of iron, riboflavin, and vitamin A but low prevalence and intensities of soil-transmitted helminth and schistosome infections. Multivariate regression analysis revealed significant associations between anemia and Plasmodium falciparum for infants, inflammation for school-aged children, and cellular iron deficiency for both school-aged children and non-pregnant women. Women with riboflavin deficiency had significantly lower odds of anemia. Our findings call for interventions to protect infants from malaria, improved intake of dietary iron, better access to health care, and health education.
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Affiliation(s)
- Aurélie A Righetti
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
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Arruda SF, Siqueira EMDA, de Valência FF. Vitamin A deficiency increases hepcidin expression and oxidative stress in rat. Nutrition 2009; 25:472-8. [PMID: 19217259 DOI: 10.1016/j.nut.2008.11.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Revised: 09/02/2008] [Accepted: 11/28/2008] [Indexed: 01/12/2023]
Abstract
OBJECTIVE The interaction between vitamin A and iron status has been widely reported; however, the exact mechanism involved in this interaction has not been well characterized. The present study investigated the mechanism involved in tissue iron accumulation and changes in the oxidative status in vitamin A-deficient rats. METHODS Rats were treated with a control diet, a vitamin A-deficient diet, or a vitamin A/iron-deficient diet for 57 d. The animals were sacrificed; the blood, liver, and spleen were collected for biochemical analysis. Analysis of variance or Mann-Whitney tests were used to compare groups and Pearson's or Spearman's tests to investigate the bivariate correlation. RESULTS Vitamin A deficiency increased liver hepcidin mRNA and iron spleen concentrations; however, iron deficiency in vitamin A-deficient rats deeply inhibits liver hepcidin mRNA expression and significantly increases divalent metal transporter-1 mRNA levels. Liver ferroportin and hereditary hemochromatosis gene mRNA levels did not change in either treatment. In the vitamin A-deficient groups, liver carbonyl protein increased, whereas catalase and glutathione S-transferase activities decreased, suggesting that vitamin A protects the liver against protein oxidation. A significant positive correlation was found between lipid oxidative damage and iron concentration in the liver and spleen (r = 0.611, P = 0.007; r = 0.558, P = 0.025, respectively). CONCLUSION These results suggest that vitamin A maintains iron homeostasis by the modulation of liver hepcidin expression. The increase of lipid peroxidation in vitamin A deficiency seems to be iron dependent, whereas protein oxidation is not.
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Affiliation(s)
- Sandra Fernandes Arruda
- Faculdade de Ciências da Saúde, Departamento de Nutrição, Campus Universitário Darcy Ribeiro, Universidade de Brasília, Asa Norte, Distrito Federal, Brazil.
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Schroeder SE, Reddy MB, Schalinske KL. Retinoic acid modulates hepatic iron homeostasis in rats by attenuating the RNA-binding activity of iron regulatory proteins. J Nutr 2007; 137:2686-90. [PMID: 18029484 DOI: 10.1093/jn/137.12.2686] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Vitamin A deficiency has been widely associated with perturbations of iron homeostasis, a consequence that can be reversed by retinoid supplementation. Despite the numerous studies that demonstrate an interaction between these 2 nutrients, the mechanistic basis for this relation has not been well characterized. Because iron regulatory proteins (IRP) have been established as central regulators of iron homeostasis, we investigated the potential role of IRP in the regulation of iron homeostasis under conditions of vitamin A deficiency and supplementation with all-trans-retinoic acid (atRA). Rats were fed a control diet or a diet deficient in either vitamin A or iron or both micronutrients. Four parallel groups of rats were supplemented with atRA daily (30 micromol/kg body weight) during the final week of this study. As expected, iron-deficient (-Fe) rats exhibited a decrease in hepatic nonheme iron levels and a subsequent increase in IRP RNA-binding activity, resulting in diminished ferritin abundance. Interestingly, atRA supplementation inhibited the increase in IRP RNA-binding activity in -Fe rats to a level that was not significantly (P = 0.139) different from control values, and it partially restored ferritin abundance. This inhibition of IRP RNA-binding activity by atRA supplementation was also associated with a 40% reduction in transferrin receptor abundance. Taken together, these results indicate that IRP represent a mechanistic link between vitamin A and the regulation of iron homeostasis, a key finding toward further understanding this important nutrient-nutrient interaction.
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Affiliation(s)
- Stacy E Schroeder
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
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Thurlow RA, Winichagoon P, Green T, Wasantwisut E, Pongcharoen T, Bailey KB, Gibson RS. Only a small proportion of anemia in northeast Thai schoolchildren is associated with iron deficiency. Am J Clin Nutr 2005. [DOI: 10.1093/ajcn/82.2.380] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Rosanne A Thurlow
- From the Institute of Nutrition, Mahidol University, Salaya, Thailand (PW, EW, TP), and Department of Human Nutrition, University of Otago, Dunedin New Zealand (RAT, KBB, and RSG)
| | - Pattanee Winichagoon
- From the Institute of Nutrition, Mahidol University, Salaya, Thailand (PW, EW, TP), and Department of Human Nutrition, University of Otago, Dunedin New Zealand (RAT, KBB, and RSG)
| | - Timothy Green
- From the Institute of Nutrition, Mahidol University, Salaya, Thailand (PW, EW, TP), and Department of Human Nutrition, University of Otago, Dunedin New Zealand (RAT, KBB, and RSG)
| | - Emorn Wasantwisut
- From the Institute of Nutrition, Mahidol University, Salaya, Thailand (PW, EW, TP), and Department of Human Nutrition, University of Otago, Dunedin New Zealand (RAT, KBB, and RSG)
| | - Tippawan Pongcharoen
- From the Institute of Nutrition, Mahidol University, Salaya, Thailand (PW, EW, TP), and Department of Human Nutrition, University of Otago, Dunedin New Zealand (RAT, KBB, and RSG)
| | - Karl B Bailey
- From the Institute of Nutrition, Mahidol University, Salaya, Thailand (PW, EW, TP), and Department of Human Nutrition, University of Otago, Dunedin New Zealand (RAT, KBB, and RSG)
| | - Rosalind S Gibson
- From the Institute of Nutrition, Mahidol University, Salaya, Thailand (PW, EW, TP), and Department of Human Nutrition, University of Otago, Dunedin New Zealand (RAT, KBB, and RSG)
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Thurlow RA, Winichagoon P, Green T, Wasantwisut E, Pongcharoen T, Bailey KB, Gibson RS. Only a small proportion of anemia in northeast Thai schoolchildren is associated with iron deficiency. Am J Clin Nutr 2005; 82:380-7. [PMID: 16087982 DOI: 10.1093/ajcn.82.2.380] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Iron deficiency is assumed to be the major cause of anemia in northeast Thailand, but other factors may be involved. OBJECTIVE We determined the prevalence of anemia among schoolchildren in northeast Thailand and the role of hemoglobinopathies, selected micronutrient deficiencies, and other factors in hemoglobin status. DESIGN Blood samples were collected from 567 children aged 6-12.9 y attending 10 primary schools for the determination of a complete blood count and hemoglobin type [Hb AA (normal hemoglobin), Hb AE (heterozygous for Hb type E), and Hb EE (homozygous for Hb type E)] and the measurement of serum ferritin, transferrin receptor, retinol, vitamin B-12, and plasma and erythrocyte folate concentrations. Children with a C-reactive protein concentration > or = 10 mg/L (n = 12), which indicated infection, were excluded. RESULTS The prevalence of anemia was 31%. Age, hemoglobin type, and serum retinol were the major predictors of hemoglobin concentration. Hb AA and Hb AE children with anemia had lower (P < 0.01) hematocrit, mean cell volume, and serum retinol values than did their nonanemic counterparts; no significant differences in serum ferritin were found by hemoglobin type. Only 16% (n = 22) of the anemic Hb AA and Hb AE children were iron deficient. Hb AA and Hb AE children with a serum retinol concentration <0.70 micromol/L (n = 14) had a significantly higher geometric mean serum ferritin concentration than did those with a retinol concentration > or = 0.70 micromol/L (P = 0.009); no significant difference in transferrin receptor concentrations was found between these 2 groups. CONCLUSIONS Hemoglobinopathies, suboptimal vitamin A status, and age were the major predictors of hemoglobin concentration. The contribution of iron deficiency to anemia was low, and its detection was complicated by coexisting suboptimal vitamin A status.
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Vasconcelos M, Datta K, Oliva N, Khalekuzzaman M, Torrizo L, Krishnan S, Oliveira M, Goto F, Datta SK. Enhanced iron and zinc accumulation in transgenic rice with the ferritin gene. PLANT SCIENCE 2003. [PMID: 0 DOI: 10.1016/s0168-9452(02)00421-1] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
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Strube YNJ, Beard JL, Ross AC. Iron deficiency and marginal vitamin A deficiency affect growth, hematological indices and the regulation of iron metabolism genes in rats. J Nutr 2002; 132:3607-15. [PMID: 12468596 DOI: 10.1093/jn/132.12.3607] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Iron deficiency and marginal vitamin A (VA) deficiency frequently coexist and affect billions of people, mostly children and women, worldwide. The effects of these micronutrient deficiencies alone and in combination on hematologic, biochemical and molecular indices of iron and VA status were investigated in a 2 x 2 randomized blocked study conducted in growing male Sprague-Dawley rats. From 3-8 wk of age, rats were fed one of four purified diets that were either adequate or restricted in iron (Fe) and adequate or marginal in VA: (+)Fe(+)VA, 20.3 and 0.367 micro g/g, respectively, denoted control diet; (-)Fe(+)VA, 3.34 and 0.405 micro g/g; (+)FeVA(m), 22.2 and 0.051 micro g/g; or (-)FeVA(m), 3.03 and 0.055 micro g/g. Weight-matched rats fed adequate micronutrients were included to control for possible confounding effects of Fe deficiency on growth and feed efficiency. Iron restriction reduced (P < 0.05) weight gain, feed efficiency, blood hemoglobin and hematocrit. Plasma and liver iron and plasma transferrin saturation were reduced by approximately 50%, whereas liver transferrin mRNA and protein and transferrin receptor mRNA were elevated, as was liver ferritin light-chain protein and light-chain mRNA. Liver heavy-chain ferritin mRNA, hemopexin, ceruloplasmin and cellular retinol-binding protein mRNA were not affected by iron or VA restriction. Although marginal VA deficiency did not exacerbate indices of poor iron status during iron deficiency, iron deficiency was associated with lower plasma retinol and elevated liver VA concentrations. These results are consistent with an impaired mobilization of liver retinol during iron deficiency as well as multiple alterations in iron metabolism.
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Affiliation(s)
- Yi Ning J Strube
- The Graduate Program in Nutrition and the Department of Nutritional Sciences, The Pennsylvania State University, University Park 16802, USA
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Semba RD, Bloem MW. The anemia of vitamin A deficiency: epidemiology and pathogenesis. Eur J Clin Nutr 2002; 56:271-81. [PMID: 11965502 DOI: 10.1038/sj.ejcn.1601320] [Citation(s) in RCA: 199] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2001] [Revised: 07/04/2001] [Accepted: 07/12/2001] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To gain insight into vitamin A deficiency as a cause of anemia. METHODS Comprehensive review of the scientific literature. RESULTS Although vitamin A deficiency is recognized to cause anemia, 'vitamin A deficiency anemia' lacks complete characterization as a distinct clinical entity. Vitamin A appears to be involved in the pathogenesis of anemia through diverse biological mechanisms, such as the enhancement of growth and differentiation of erythrocyte progenitor cells, potentiation of immunity to infection and reduction of the anemia of infection, and mobilization of iron stores from tissues. Epidemiological surveys show that the prevalence of anemia is high in populations affected by vitamin A deficiency in developing countries. Improvement of vitamin A status has generally been shown to reduce anemia, but the actual public health impact on anemia is unclear. CONCLUSIONS Further work is needed to elucidate the biological mechanisms by which vitamin A causes anemia. The inclusion of anemia as an outcome measure in future micronutrient intervention studies should help provide further insight into the anemia of vitamin A deficiency.
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Affiliation(s)
- R D Semba
- Department of Ophthalmology Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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