Increased Infectious Disease Morbidity and Mortality

Vitamin A deficiency increases susceptibility to some types of infections, and there is currently an extensive literature regarding vitamin A deficiency and infection in experimental animal models, as can be found in reviews elsewhere (440,474-477). Vitamin A supplementation or fortification has been shown to reduce the morbidity and mortality of diarrheal diseases among preschool children in developing countries. The reduction in diarrheal disease mortality appears to account for most of the...

Risk Factors for Vitamin A Deficiency

Vitamin A deficiency is more common among poor families in developing countries, and along with poverty are many associated risk factors such as low maternal and paternal education, lack of land, crowding, poor hygiene, increased infectious disease morbidity, geographic isolation, lack of a home garden, and inadequate intake of vitamin A. Infants, preschool, and primary school-aged children are at higher risk for vitamin A deficiency, Fig. 17. Risk factors for vitamin A deficiency. Fig. 17....

Growth Retardation

Growth retardation is common among children in developing countries and is considered the best global indicator of physical well-being in children (498). It has long been known that vitamin A-deficient animals exhibit growth failure. Retinoic acid is known to regulate growth hormone gene expression (499). In Indonesia, children with xerophthalmia had reduced linear and ponderal growth (500). Clinical trials show that vitamin A supplementation has an impact on growth, but these effects are...

Dietary Requirements for Vitamin A

The Food and Nutrition Board of the Institute of Medicine has made new recommendations of vitamin A intake by life stage and gender group (Table 2) (246). These Dietary Reference Intakes (DRIs) are reference values that are quantitative estimates of nutrient intakes to be used for planning and assessing diets in apparently healthy people and include Recommended Dietary Allowances (RDAs), Estimated Average Requirement (EAR), and Adequate Intake (AI) (246). The RDA is defined as the dietary...

Retinoic Acid Receptors and Gene Regulation

Vitamin A exerts its effects via retinoic acid and retinoid receptors, which are found in the nucleus of the cell. Retinol is converted to all-trans-retinoic acid and 9-cis retinoic acid in the cytoplasm. Retinoic acid influences gene activation through specific receptors which belong to the superfamily of thyroid and steroid receptors (231). Retinoic acid receptors (RARs) act as transcriptional activators for many specific target genes. The R AR is expressed as isoforms, referred to as RAR a,...

Clinical Diagnosis

Vitamin A deficiency can be diagnosed on the basis of clinical signs and symptoms as described under Subheading 3. The most commonly used clinical indicators of vitamin A deficiency are night blindness and Bitot spots. Although the earlier literature may refer to night blindness and Bitot spots as mild vitamin A deficiency, the presence of clinical vitamin A deficiency actually represents a later, more severe state of vitamin A deficiency. A simple history of night blindness can be used as a...

Vitamin A Deficiency Infection and Mortality in Developing Countries A Recurring Theme

With improvements in nutrition, hygiene, and living standards, vitamin A deficiency gradually disappeared from Europe and the United States. The Joint Food and Agricultural Organization (FAO) WHO) Expert Committee on Nutrition focused on vitamin A deficiency as a public health problem in developing countries in the 1950s. The FAO WHO Expert Committee on Nutrition recognized that dried skimmed milk production had increased greatly after World War II, and that it was a surplus food being...

Characterization of Vitamin A

The existence of vitamin A was shown through a long process that spanned a period of over 130 yr. More than 60 yr after Magendie's experiments with dogs, Nicolai Lunin (1853-1937) and Carl Socin at the University of Dorpat showed that mice could not survive on purified protein, fat, carbohydrate, and mineral salts alone, but were able to survive if supplemented with milk or egg yolk (28,29). Cornelis Pekelharing (1848-1922) and Frederick Hopkins (1861-1947) both conducted studies that also...

Ellisons Landmark Trial and Other Therapeutic Trials of Vitamin A the Anti Infective Vitamin 19201940

Vitamin A became known as the anti-infective vitamin, and from 1920 through 1940, this vitamin underwent considerable evaluation in at least 30 therapeutic trials, from dental caries to pneumonia to measles. These studies were conducted during a period when there was an increased awareness of the problem of infant and child mortality in Europe Fig. 2. Frequency distribution of 72 children admitted to the Rigshospital, Copenhagen for xerophthalmia from 1912 to 1919. (Reprinted from ref. 48.)...

Dietary Sources and Metabolism of Vitamin A 321 Food Sources of Vitamin A

Vitamin A is available in dietary sources as either preformed vitamin A or as provitamin A carotenoids. Rich dietary sources of preformed vitamin A include egg yolk, liver, butter, cheese, whole milk, and cod-liver oil. In animal foods, vitamin A is mostly in the form of retinyl esters, such as retinyl palmitate. In many developing countries, the consumption of foods containing preformed vitamin A is limited, and provitamin A carotenoids often comprise the major dietary source of vitamin A...

Control of Infectious Diseases

Given the close relationship between some infectious diseases and vitamin A deficiency, the control of diseases such as measles (598) and diarrheal diseases would likely reduce the risk of xerophthalmia among infants and preschool children. Thus, programs aimed at more effective measles vaccines, prevention of diarrheal diseases, and malaria control would likely have an effect on reducing xerophthalmia. Treatment of intestinal parasites such as Ascaris lumbricoides may help to improve the...

Info

To Tom, Lisa, and Amy, for our wonderful friendship and adventures from Palo Alto to Paris and Puebla Handbook of Nutrition and Ophthalmology, by Richard D. Semba, 2007 Adipose Tiss ue and Adipokines in Health and Disease, edited by Giamila Fantuzzi and Theodore Mazzone, 2007 Nutritional Health Strategies for Disease Prevention, Second Edition, edited by Norman J. Temple, Ted Wilson and David R. Jacobs, Jr., 2006 Nutrients, Stress, and Medical Disorders, edited by Shlomo Yehuda and David I....

Prevalence and Incidence

Worldwide, there are an estimated 140 million preschool children and 7.2 million pregnant women who have vitamin A deficiency (597). In low-income countries worldwide, there are an estimated 453,000 children with blindness or severe visual impairment, and 200,000 have corneal scarring attributed mostly to measles and vitamin A deficiency (2). There is a close synergism between measles and vitamin A deficiency that can result in blindness, and of an estimated 30 million children who develop...

Of Vitamin A Supplementation in the Early 1970s

Community-based high-dose vitamin A supplementation was advocated by several scientists (116-118). A 4-yr field study conducted in India in the late 1960s showed that an annual dose of 300,000 IU of vitamin A to children aged 1 to 5 yr reduced the prevalence of Bitot spots and keratomalacia (119). In 1971, a national program to distribute high-dose vitamin A capsules, 200,000 IU every 6 mo, to all children between the ages of 1 and 5 yr was initiated in India (120,121). The distribution of...

Immune Suppression and Inflammation

Vitamin A modulates many different aspects of immune function, both nonspecific (innate) immunity (i.e., maintenance of mucosal surfaces, natural killer (NK) cell activity, and phagocytosis) and specific (adaptive) immunity (i.e., generation of antibody responses). Some aspects of immunity are not affected by vitamin A deficiency. Much of our knowledge of vitamin A and immune function is based on experimental animal studies involving mice, rats, and chickens, and from in vitro studies involving...

Global Distribution

The prevalence of vitamin A deficiency is higher in developing countries in southeast Asia, south Asia, east Asia and the Pacific region, sub-Saharan Africa, the Middle East, northern Africa, and Central and South America (Fig. 15) (600,601). Vitamin A deficiency is considered a public health problem in about 78 countries worldwide, and the geographical distribution of vitamin A deficiency follows the same general pattern as for poverty, malnutrition, and greater burden of infectious diseases...

Assessment of Vitamin A Status

A wide variety of methods are available to assess vitamin A status, and the more commonly utilized techniques include serum retinol concentrations, breast milk retinol concentrations, conjunctival impression cytology, dark adaptometry, RDR test, and modified relative dose response (MRDR) test (973,974). Liver retinol concentrations are often considered the gold standard for vitamin A status, but liver biopsy is highly invasive and rarely used s. The methods for the assessment of vitamin A...

Xerophthalmia and Keratomalacia

Who And Xerophthalmia

The WHO classification of xerophthalmia is shown in Table 3. This classification was first adopted in 1976 126 , with minor modification in 1982 247 . The ocular signs are Fig. 5. Night blindness in a public health poster from Indonesia. Fig. 5. Night blindness in a public health poster from Indonesia. classified in order of severity from night blindness XN to corneal ulceration and kera-tomalacia that involves one-third of the cornea or greater X3B . A corneal scar XS is not a sign of active...

Vitamin A Deficiency and Increased Mortality in Children Lessons From Denmark

From 1909 to 1920, the Danish ophthalmologist Olaf Blegvad 1888-1961 documented cases of xerophthalmia, or clinical vitamin A deficiency, among children in Denmark 48 . From 1911 to 1917, there was a strong, gradual increase in the number of cases of keratomalacia, the most severe eye lesion of vitamin A deficiency, followed by a decline in 1918 and 1919 and then an increase in 1920. During the same period in neighboring Sweden, there was no epidemic of xerophthalmia. Blegvad showed that the...