Vitamin A deficiency

About: Vitamin A deficiency is a research topic. Over the lifetime, 3626 publications have been published within this topic receiving 90394 citations. The topic is also known as: hypovitaminosis A & Deficiency, Vitamin A.

Vitamin A, infection, and immune function.

Abstract: In populations where vitamin A availability from food is low, infectious diseases can precipitate vitamin A deficiency by decreasing intake, decreasing absorption, and increasing excretion. Infectious diseases that induce the acute-phase response also impair the assessment of vitamin A status by transiently depressing serum retinol concentrations. Vitamin A deficiency impairs innate immunity by impeding normal regeneration of mucosal barriers damaged by infection, and by diminishing the function of neutrophils, macrophages, and natural killer cells. Vitamin A is also required for adaptive immunity and plays a role in the development of T both-helper (Th) cells and B-cells. In particular, vitamin A deficiency diminishes antibody-mediated responses directed by Th2 cells, although some aspects of Th1-mediated immunity are also diminished. These changes in mucosal epithelial regeneration and immune function presumably account for the increased mortality seen in vitamin A-deficient infants, young children, and pregnant women in many areas of the world today.

Vitamin A Deficiency: Health, Survival, and Vision

Abstract: This book on vitamin A deficiency not only addresses ocular manifestations but also the broader context of child health and survival. The introduction examines the historical and modern perspectives of vitamin deficiency what vitamin A is and the relationship of xerophthalmia (severe vitamin A deficiency) to vitamin A status. The second section of the book discusses consequences of vitamin A deficiency. Chapter 2 looks at mortality associated with moderate to severe deficiency and the fact that vitamin A supplementation reduces preschool-age mortality and measles mortality. Chapter 3 covers infectious morbidity particularly diarrhea measles respiratory disease urinary tract infection otitis and other infections (e.g. HIV). Chapter 4 examines ocular manifestations (xerophthalmia keratomalacia night blindness and conjunctiva). The effect of vitamin A on anemia and iron metabolism and the extent of vitamin A deficiency-associated anemia are discussed in chapter 5. Chapter 6 examines vitamin As role in growth in animals and children. The third section of the book is dedicated to mechanisms of vitamin A. Chapter 7 looks at contributory and precipitating events (i.e. systemic infections and protein energy malnutrition). Chapter 8 addresses the biochemistry of vitamin A and carotenoids. Chapter 9 examines the relationship between immunocompetence and vitamin A status particularly lymphoid organs and hematopoiesis cell-mediated immunity humoral immunity effect of vitamin A administration on immune response and identification of and requirements for immunoregulatory retinoids. The fourth section chapter 10 is dedicated to treatment of vitamin A deficiency and xerophthalmia. The last section covers assessment and prevention. Chapters 11 and 12 discuss assessment of vitamin A status and epidemiology of deficiency respectively. The last three chapters examine prevention interventions: dietary interventions supplementation and fortification of dietary items with vitamin A.

A Food-Based Approach Introducing Orange-Fleshed Sweet Potatoes Increased Vitamin A Intake and Serum Retinol Concentrations in Young Children in Rural Mozambique

Abstract: Vitamin A deficiency is widespread and has severe consequences for young children in the developing world. Food-based approaches may be an appropriate and sustainable complement to supplementation programs. Orange-fleshed sweet potato (OFSP) is rich in b-carotene and is well accepted by young children. In an extremely resource poor area in Mozambique, the effectiveness of introduction of OFSP was assessed in an integrated agriculture and nutrition intervention, which aimed to increase vitamin A intake and serum retinol concentrations in young children. The 2-y quasiexperimental intervention study followed households and children (n ¼ 741; mean age 13 mo at baseline) through 2 agricultural cycles. In y 2, 90% of intervention households produced OFSP, and mean OFSP plot size in intervention areas increased from 33 to 359 m 2 . Intervention children (n ¼ 498) were more likely than control children (n ¼ 243) to eat OFSP 3 or more d in the last wk (55% vs. 8%, P , 0.001) and their vitamin A intakes were much higher than those of control children (median 426 vs. 56 mg retinol activity equivalent, P , 0.001). Controlling for infection/inflammation and other confounders, mean serum retinol increased by 0.100 mmol/L (SEM 0.024; P , 0.001) in intervention children and did not increase significantly in control subjects. Integrated promotion of OFSP can complement other approaches and contribute to increases in vitamin A intake and serum retinol concentrations in young children in rural Mozambique and similar areas in Sub-Saharan Africa. J. Nutr. 137: 1320‐1327, 2007.