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

Collagene Collagenase Gene Promoters

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...