Vitamin A supplementation

Klamt, F, Dal-Pizzol, F, Roehrs, R, de Oliveira, RB, Dalmolin, R, Henriques, JAP, de Andrades, HHR, Ramos, A, Saffi, J, and Moreira, JCF, 2003. Genotoxicity, recombinogenicity and cellular preneoplasic transformation induced by vitamin A supplementation. Mutat Res Genet Toxicol Environ Mutagen 539, 117-125. 

Studies in humans and animals suggest that carotenoid absorption depends on several factors including vitamin A status. Sklan and others (1989) demonstrated that vitamin A supplementation reduced (3-carotene and canthaxanthin absorption in chickens. Dietary carotenoids absorption and bioconversion to vitamin A varied inversely with the vitamin A status of Philippine children (Ribaya-Mercado and others 2000). Some studies (Lecomte and others 1994 Albanes and others 1997) have suggested a possible negative effect of alcohol consumption on carotenoid absorption however,... 

Vitamin A is essential for growth and development of cells and tissues. In its active form, retinoic acid (RA), it controls the regular differentiation as a ligand for retinoic acid receptors (RAR, RXR) and is involved in the integration (gap junction formation) of cell formations (Biesalski, 1996 Biesalski et al, 1999). Vitamin A plays a substantial role, especially in the respiratory epithelium and the lung. During moderate vitamin A deficiency, the incidence for diseases of the respiratory tract is considerably increased and repeated respiratory infections can be influenced therapeutically by a moderate vitamin A supplementation (Biesalski et ah, 2001 Greenberg et ah, 1997 John et ah, 1997). 

Aukrust, P., Mulle, F., Ueland, T., Svardal, A. M., Berge, R. K., and Froland, S. S. (2000). Decreased vitamin A levels in common variable immunodeficiency Vitamin A supplementation in vivo enhances immunoglobulin production and downregulates inflammatory response. Eur. J. Clin. Invest. 30, 252-259. 

Barreto, M. L., Santos, L. M., Assis, A. M., Araujo, M. P., Farenzena, G. G., Santos, P. A., and Fiaccone, R. L. (1994). Effect of vitamin A supplementation on diarrhoea and acute lower-respiratory-tract infections in young children in Brazil. Lancet 344, 228-231. 

Pearson, E., Bose, C., Snidow, T., Ransom, L., Young, T., Bose, G., and Stiles, A. (1992). Trial of vitamin A supplementation in very low birth weight infants at risk for bronchopulmonary dysplasia. /. Pediatr. 121, 420-427. 

Ramakrishnan, U., Latham, M. C., Abel, R., and Frongillo, E. A., Jr. (1995a). Vitamin A supplementation and morbidity among preschool children in South India. Am. J. Clin. Nutr. 61,1295-1303. 

Rahmathullah, L., Underwood, B. A., Thulasiraj, R. D., and Milton, R. C. (1991). Diarrhea, respiratory infections and growth are not affected by a weekly low-dose vitamin A supplement A masked, controlled field trial in children in Southern India. Am. J. Clin. Nutr. 54, 568-577. 

Sommer, A. (1993). Vitamin A supplementation and childhood morbidity. Lancet 342, 1420-1424. 

Vitamin A can suppress many chemically induced tumors in the laboratory. Epidemiological evidence suggests that foods rich in carotenes or vitamin A are associated with a lower risk of cancer. However, the use of vitamin A supplementation is not advised because of the toxicities produced by large amounts of this vitamin. 

In higher plants, carotenoids are produced in green leaves. In animals, conversion of carotenoids to vitamin A occurs in the intestinal wall. Storage is in the liver also kidney in rat and cat. Target tissues are retina, skin, bone, liver, adrenals, germinal epithelium. Commercial Vitamin A supplements are obtained chemically by extraction of fish liver or synthetically from citral or /3-ionone. 

People with severe hypertriglyceridemia associated with Type V hyperlipoproteinemia may be at increased risk of hypervitaminosis A, even with moderate degrees of vitamin A supplementation (1199). Long-term vitamin A administration is associated with an increase in serum cholesterol and serum triglyceride concentrations (1200) and consequently might be linked with atherosclerosis (SEDA-8, 345) (1201,1202). 

In addition to proteins and calories, the patients with PEM must be replenished with respect to vitamins and micronutrients especially to enhance antioxidant status. Due to heavy vitamin A losses that occur during infections and PEM, vitamin A supplements are necessary to prevent blindness. Selenium, zinc, manganese, and cobalt are important micronutrients deficient in patients with PEM and therefore need to be replaced. These micronutrients play a vital role in the function of several enzymes (e.g., selenium in glutathione peroxidase). Iron must be excluded from the diet in the initial stage since early administration increases the risk of free-radical production and infection. 

The eradication of vitamin A deficiency in Thailand did not arise from a government program focused specifically on vitamin A deficiency but rather from a comprehensive national program to promote primary health care in local communities. Vitamin A supplements were administered only to children who showed eye symptoms but not to all children deemed to be at risk of vitamin A deficiency. The program was... 

WHO, UNICEF, IVACG Task Force Vitamin A Supplements. A Guide to Their Use In the Treatment and Prevention of Vitamin A Deficiency and Xerophthalmia. 2nd ed. World Health Organization, Geneva, 1997. 

Maisey J, Miller K (1986) Assessment of the ability of mice fed on vitamin A supplemented diet to respond to a variety of potential contact sensitizers. Contact Dermatitis 15(1) 17—23... 

Vitamin A deficiency is a major problem of children under five in developing countries, being the single most common preventable cause of blindness. Table 2.1 shows the prevalence of vitamin A deficiency in different regions of the world. The increased susceptibility to infection and impairment of immune responses in vitamin A deficiency causes significant childhood mortality. A number of trials of vitamin A supplementation in areas of endemic deficiency show a 20% to 35% reduction in child mortality. 

A mild infection, such as measles, commonly triggers the development of xerophthalmia in children whose vitamin A status is marginal. In addition to functional deficiency as a result of impaired synthesis of RBP (Section 2.2.3) and transthyretin in response to infection, there may be a considerable urinary loss of vitamin A because of increased renal epithelial permeability and proteinuria, permitting loss of retinol bound to RBP-transthyretin. The American Academy of Pediatrics Committee on Infectious Diseases (1993) recommended vitamin A supplements for aU children who have been hospitalized with measles. 

Kumar MV, Sunvold GD, and Scarpace PJ (1999) Dietary vitamin A supplementation in rats suppression of leptin and induction of UCPl mRNA. Journal of Lipid Research 40, 824-9. 

Arnhold T, Nau H, Meyer S, Rothkoetter HJ, and Lampen AD (2002) Porcine intestinal metabolism of excess vitamin A differs following vitamin A supplementation and liver consumption./owma/ of Nutrition 132,197-203. 

Although rarely encountered in developed countries, vitamin A deficiency remains a global public health problem. The current World Health Organization recommendation for vitamin A treatment in children 1 year of age and older who are at risk (see Table 17-3) is one 200,000 lU oral dose every 3 to 6 months for prophylaxis, and three such doses for treatment and prevention of xerophthalmia. Animal studies (rat model) have shown some improvement in corneal epithelial fimction with topical vitamin A supplementation. In human trials, evidence is contradictory regarding the beneficial role of topical vitamin A application. The apparent mechanism is reduction of inflammatory components. 

Katz J, West KP Jr, Khatry SK, et al. Impact of vitamin A supplementation on prevalence and incidence of xerophthalmia in Nepal. Invest Ophthalmol Vis Sci 1995 36 2577-2583. 

Red palm oil is the richest source of readily available carotenoids and is, therefore, very useful as a pro-Vitamin A supplement. Crude palm oil contains 500-800 ppm of carotenoids, of which (3-carotene and a-carotene account for about 90% (approximately 2 1 w/w), and lycopene, phytoene, and zeacarotenes are inter alias the remaining carotenoids (60). Other vegetable oils contain much lower levels of carotenoids (<100 ppm), but these are removed during the bleaching step in... 

Fraser D R1995 Vitamin D. Lancet 345 104-107 Greenberg E R, Spom M B1996 Antioxidant vitamins, cancer and cardiovascular disease. New England Journal of Medicine 334 1198-1190 Humphrey J H, Rice A L 2000 Vitamin A supplementation in young infants. Lancet 356 422-424... 

Vitamin A supplementation programs have been used in Indonesia, the Phi lip-pi lies, and Africa, where they have resulted in moderate reductions in child mortality and dramatic decreases in the incidence of nightblindness and xerophthalmia. Public health workers have used the following schedule for preventing xerophthalmia and increasing the liver s resen es of vitamin A. Oral retinyl pa Imitate (110 mg), ret In y I acetate (6f> mg), or injected retinyl palmitate (. 5 mg) are administered on each of two successive days, and once a few weeks later if symptoms are not relieved, One approach that seems to be especially workable is to give high-dose capsules at the hme of a scheduled immunization. One clei- er... 

Arthur P, Bahl P, Bhan MK, Kirkwood BR, Martines J, Moulton LH, Panny ME, Ram M, Ram M, Underwood B. Randomised trial to assess benefits and safety of vitamin A supplementation linked to immunisation in early infancy. WHO/CHD Immunisation-Linked Vitamin A Supplementation Study Group. Lancet 1998 352(9136) 1257-63. 

Stephensen CB, Franchi LM, Hernandez H, Campos M, Gilman RH, Alvarez JO. Adverse effects of high-dose vitamin A supplements in children hospitalized with pneumonia. Pediatrics 1998 101(5) E3. 

In alcohohcs vitamin A supplementation, which might be a useful therapeutic measure, is complicated by the hepatotoxicity of large doses of the vitamin and the fact that chronic alcohol consumption results in an enhanced susceptibility to this effect (87). 

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