Andere beliebte Artikel

Learn all about Vitamin A

Also indexed as: A Vitamin, Retinol (Vitamin A)

How to take Vitamin A

For most people, up to 25,000 IU (7,500 mcg) of vitamin A per day is considered safe. However, people over age 65 and those with liver disease should probably not supplement with more than 15,000 IU per day, unless supervised by a doctor. In women who could become pregnant, the maximum safe intake is being re-evaluated. However, less than 10,000 IU (3,000 mcg) per day is generally accepted as safe. There is concern that larger intakes could cause birth defects. Whether the average person would benefit from vitamin A supplementation remains unclear.

Where to Find It

Liver, dairy products, and cod liver oil are good sources of vitamin A. Vitamin A is also available in supplement form.

Possible Deficiencies

People who limit their consumption of liver, dairy foods, and beta-carotene-containing vegetables can develop a vitamin A deficiency. Extremely low birth weight babies (2.2 pounds or less) are at high risk of being born with a deficiency, and vitamin A shots given to these infants have been reported in double-blind research to reduce the risk of lung disease. The earliest deficiency sign is poor night vision. Deficiency symptoms can also include dry skin, increased risk of infections, and metaplasia (a precancerous condition). Severe deficiencies causing blindness are extremely rare in Western societies.

Less severe deficiencies are more likely to occur with a variety of conditions causing malabsorption. A high incidence of vitamin A deficiency in people infected with HIV has also been reported. People with hypothyroidism have an impaired ability to convert beta-carotene to vitamin A. For this reason, some doctors suggest taking supplemental vitamin A (perhaps 5,000–10,000 IU per day) if they are not consuming adequate amounts in their diet.

Very old people with type 2 diabetes have shown a significant age-related decline in blood levels of vitamin A, irrespective of their dietary intake.

References

1. Little DR. Ambulatory management of common forms of anemia. Am Fam Physician 1999;59:1598–604 [review].

2. Hodges RE, Sauberlich HE, Canham JE, et al. Hematopoietic studies in vitamin A deficiency. Am J Clin Nutr 1978;31:876–85 [review].

3. Bloem MW. Interdependence of vitamin A and iron: an important association for programmes of anaemia control. Proc Nutr Soc 1995;54:501–8 [review].

4. Lane M, Alfrey CP. The anemia of human riboflavin deficiency. Blood 1965;25:432–42.

5. Orehek AJ, Kollas CD. Refractory postpartum anemia due to vitamin B6 deficiency. Ann Intern Med 1997;126(10):834–5 [letter].

6. Iwama H, Iwase O, Hayashi S, et al. Macrocytic anemia with anisocytosis due to alcohol abuse and vitamin B6 deficiency. Rinsho Ketsueki 1998;39:1127–30 [in Japanese].

7. Hirschmann JV, Raugi GJ. Adult scurvy. J Am Acad Dermatol 1999;41:895–906 [review].

8. Summerfield AL, Steinberg FU, Gonzalez JG. Morphologic findings in bone marrow precursor cells in zinc-induced copper deficiency anemia. Am J Clin Pathol 1992;97:665–8.

9. Freycon F, Pouyau G. Rare nutritional deficiency anemia: deficiency of copper and vitamin E. Sem Hop 1983;59:488–93 [review] [in French].

10. Borgna-Pignatti C, Marradi P, Pinelli L, et al. Thiamine-responsive anemia in DIDMOAD syndrome. J Pediatr 1989;114:405–10.

11. Neufeld EJ, Mandel H, Raz T, et al. Localization of the gene for thiamine-responsive megaloblastic anemia syndrome, on the long arm of chromosome 1, by homozygosity mapping. Am J Hum Genet 1997;61:1335–41.

12. Benn CS, Aaby P, Bale C, et al. Randomised trial of effect of vitamin A supplementation on antibody response to measles vaccine in Guinea-Bissau, west Africa. Lancet 1997;350:101–5.

13. Semba RD. Vitamin A as “anti-infective” therapy, 1920–1940. J Nutr 1999;129:783–91 [review].

14. Molina EL, Patel JA. A to Z: vitamin A and zinc, the miracle duo. Indian J Pediatr 1996;63:427–31 [review].

15. Malvy D. Micronutrients and tropical viral infections: one aspect of pathogenic complexity in tropical medicine. Med Trop (Mars) 1999;59:442–8 [review; in French].

16. World Health Organization. Expanded programme on immunization: programme for the prevention of blindness nutrition. Joint WHO/UNICEF statement. Vitamin A for measles. Wkly Epidemiol Rec 1987;62:133–4.

17. Coutsoudis A, Broughton M, Coovadia HM. Vitamin A supplementation reduces measles morbidity in young African children: a randomized, placebo-controlled, double-blind trial. Am J Clin Nutr 1991;54:890–5.

18. Rosales FJ, Kjolhede C. A single 210-mumol oral dose of retinol does not enhance the immune response in children with measles. J Nutr 1994;124:1604–14.

19. Rahmathullah L. Effect of receiving a weekly dose of vitamin A equivalent to the recommended dietary allowances among pre school children on mortality in south India. Indian J Pediatr 1991;58:837–47.

20. Vijayaraghavan K, Rashmiah G, Suryaprakasam B, et al. Effect of massive dose of vitamin A on morbidity and mortality in Indian children. Lancet 1990;336:1342–53.

21. Glasziou PP, Mackerras DE. Vitamin A supplementation in infectious diseases: a meta-analysis. BMJ 1993;306:366–70 [review].

22. Frieden TR, Sowell AL, Henning JK, et al. Vitamin A levels and severity of measles: New York City. Am J Dis Child 1992;146:182–6.

23. Committee on Infectious Diseases, American Academy of Pediatrics. Vitamin A treatment of Measles. Pediatrics 1993;91:1014–5.

24. Coutsoudis A, Coovadia HM, Broughton M, et al. Micronutrient utilisation during measles treated with vitamin A or placebo. Int J Vitam Nutr Res 1991;61:199–204.

25. Campos FA, Flores H, Underwood BA. Effect of an infection on vitamin A status of children as measured by the relative dose response. Am J Clin Nutr 1987;46:91–4.

26. Ozsoylu S, Cemeroglu AP, Gunay M. Vitamin A for varicella. J Pediatr 1994;125:1017–8 [letter].

27. Turck D, Michaud L. Cystic fibrosis: nutritional consequences and management. Baillieres Clin Gastroenterol 1998;12:805–22 [review].

28. Lindemans J, Neijens HJ, Kerrebijn KF, Abels J. Vitamin B12 absorption in cystic fibrosis. Acta Paediatr Scand 1984;73:537–40.

29. Gueant JL, Vidailhet M, Pasquet C, et al. Effect of pancreatic extracts on the faecal excretion and on the serum concentration of cobalamin and cobalamin analogues in cystic fibrosis. Clin Chim Acta 1984;137:33–41.

30. Semba RD. Vitamin A, immunity, and infection. Clin Infect Dis 1994;19:489–99 [review].

31. Glasziou PP, Mackerras DEM. Vitamin A supplementation in infectious diseases: a meta-analysis. BMJ 1993;306:366–70.

32. Stephensen CB, Franchi LM, Hernandez H, et al. Adverse effects of high-dose vitamin A supplements in children hospitalized with pneumonia. Pediatrics 1998;101(5):E3 [abstract].

33. Bresee JS, Fischer M, Dowell SF, et al. Vitamin A therapy for children with respiratory syncytial virus infection: a multicenter trial in the United States. Pediatr Infect Dis J 1996;15:777–82.

34. Quinlan KP, Hayani KC. Vitamin A and respiratory syncytial virus infection. Serum levels and supplementation trial. Arch Pediatr Adolesc Med 1996;150:25–30.

35. Kjolhede CL, Chew FJ, Gadomski AM, et al. Clinical trial of vitamin A as adjuvant treatment for lower respiratory tract infections. J Pediatr 1995;126:807–12.

36. Pinnock CB, Douglas RM, Badcock NR. Vitamin A status in children who are prone to respiratory tract infections. Aust Paediatr J 1986;22:95–9.

37. Murphy S, West KP Jr, Greenough WB 3d, et al. Impact of vitamin A supplementation on the incidence of infection in elderly nursing-home residents: a randomized controlled trial. Age Ageing 1992;21:435–9.

38. Fawzi WW, Mbise R, Spiegelman D, et al. Vitamin A supplements and diarrheal and respiratory tract infections among children in Dar es Salaam, Tanzania. J Pediatr 2000;137:660–7.

39. Ross AC. Vitamin A supplementation as therapy—are the benefits disease specific? Am J Clin Nutr 1998;68:8–9 [review].

40. Fawzi WW, Mbise RL, Fataki MR, et al. Vitamin A supplementation and severity of pneumonia in children admitted to the hospital in Dar es Salaam, Tanzania. Am J Clin Nutr 1998;68:187–92.

41. Stich HF, Rosin MP, Hornby AP, et al. Remission of oral leukoplakias and micronuclei in tobacco/betel quid chewers treated with beta-carotene and with beta-carotene plus vitamin A. Int J Cancer 1988;42:195–9.

42. Garewal HS, Katz RV, Meyskens F, et al. ß-Carotene produces sustained remission in patients with oral leukoplakia. Arch Otolaryngol Head Neck Surg 1999;125:1305–10.

43. Liede K, Hietanen J, Saxen L, et al. Long-term supplementation with alpha-tocopherol and beta-carotene and prevalence of oral mucosal lesions in smokers. Oral Dis 1998;4:78–83.

44. Toma S, Benso S, Albanese E, et al. Treatment of oral leukoplakia with beta-carotene. Oncology 1992;49:77–81.

45. Garewal HS, Meyskens FL Jr, Killen D, et al. Response of oral leukoplakia to beta-carotene. J Clin Oncol 1990;8:1715–20.

46. Lippman SM, Batsakis JG, Toth BB, et al. Comparison of low-dose isotretinoin with beta carotene to prevent oral carcinogenesis. N Engl J Med 1993;328:15–20.

47. Johnson J, Ringsdorf W, Cheraskin E. Relationship of vitamin A and oral leukoplakia. Arch Derm 1963;88:607–12.

48. Stich HF, Mathews B, Sankaranarayanan R, Nair MK. Remission of precancerous lesions in the oral cavity of tobacco chewers and maintenance of the protective effect of ß-carotene or vitamin A. Am J Clin Nutr 1991;53:298S–304S.

49. Stich HF, Rosin MP, Hornby AP, et al. Remission of oral leukoplakias and micronuclei in tobacco/betel quid chewers treated with beta-carotene and with beta-carotene plus vitamin A. Int J Cancer 1988;42:195–9.

50. Rumore MM. Vitamin A as an immunomodulating agent. Clin Pharm 1993;12:506–14 [review].

51. West CE. Vitamin A and measles. Nutr Rev 2000;58:S46–S54.

52. Glasziou PP, Mackerras DE. Vitamin A supplementation in infectious diseases: a meta-analysis. BMJ 1993;306:366–70.

53. Markowitz LE, Nzilambi N, Driskell WJ, et al. Vitamin A levels and mortality among hospitalized measles patients, Kinshasa, Zaire. J Trop Pediatr 1989;35:109–12.

54. Arrieta AC, Zaleska M, Stutman HR, Marks MI. Vitamin A levels in children with measles in Long Beach, California. J Pediatr 1992;121:75–8.

55. Butler JC, Havens PL, Sowell AL, et al. Measles severity and serum retinol (vitamin A) concentration among children in the United States. Pediatrics 1993;91:1176–81.

56. Frieden TR, Sowell AL, Henning KJ, et al. Vitamin A levels and severity of measles. New York City. Am J Dis Child 1992;146:182–6.

57. Glasziou PP, Mackerras DE. Vitamin A supplementation in infectious diseases: a meta-analysis. BMJ 1993;306:366–70.

58. Fawzi WW, Chalmers TC, Herrera MG, Mosteller F. Vitamin A supplementation and child mortality. A meta-analysis. JAMA 1993;269:898–903.

59. Barclay AJ, Foster A, Sommer A. Vitamin A supplements and mortality related to measles: a randomised clinical trial. BMJ 1987;294:294–6.

60. Glasziou PP, Mackerras DE. Vitamin A supplementation in infectious diseases: a meta-analysis. BMJ 1993;306:366–70.

61. Hussey GD, Klein M. A randomized, controlled trial of vitamin A in children with severe measles. N Engl J Med 1990;323:160–4.

62. Kawasaki Y, Hosoya M, Katayose M, Suzuki H. The efficacy of oral vitamin A supplementation for measles and respiratory syncytial virus (RSV) infection. Kansenshogaku Zasshi 1999;73:104–9 [in Japanese].

63. Ellison JB. Intensive vitamin A therapy in measles. BMJ 1932;2:708–11.

64. Russell RM, Smith VC, Multak R, et al. Dark-adaptation testing for diagnosis of subclinical vitamin-A deficiency and evaluation of therapy. Lancet 1973;2:1161–4.

65. Singh RB, Niaz MA, Sharma JP, et al. Plasma levels of antioxidant vitamins and oxidative stress in patients with acute myocardial infarction. Acta Cardiol 1994;49:441–52.

66. Levy Y, Bartha P, Ben-Amotz A, et al. Plasma antioxidants and lipid peroxidation in acute myocardial infarction and thrombolysis. J Am Coll Nutr 1998;17:337–41.

67. Singh RB, Niaz MA, Rastogi SS, Tastogi S. Usefulness of antioxidant vitamins in suspected acute myocardial infarction (the Indian experiment of infarct survival-3). Am J Cardiol 1996;77:232–6.

68. Kardinaal AFM, Kok FJ, Ringstad J, et al. Antioxidants in adipose tissue and risk of myocardial infarction: the EURAMIC study. Lancet 1993;342:1379–84.

69. Tavani A, Negri E, D’Avanzo B, La Vecchia C. Beta-carotene intake and risk of nonfatal acute myocardial infarction in women. Eur J Epidemiol 1997;13:631–7.

70. Rapola JM, Virtamo J, Ripatti S, et al. Randomised trial of alpha-tocopherol and beta-carotene supplements on incidence of major coronary events in men with previous myocardial infarction. Lancet 1997;349:1715–20.

71. Virtamo J, Rapola JM, Ripatti S, et al. Effect of vitamin E and beta carotene on the incidence of primary nonfatal myocardial infarction and fatal coronary heart disease. Arch Intern Med 1998;158:668–75.

72. Klipstein-Grobusch K, Geleijnse JM, den Breeijen JH, et al. Dietary antioxidants and risk of myocardial infarction in the elderly: the Rotterdam Study. Am J Clin Nutr 1999;69:261–6.

73. Semba RD. Vitamin A, immunity, and infection. Clin Infect Dis 1994;19:489–99 [review].

74. Glasziou PP, Mackerras DEM. Vitamin A supplementation in infectious diseases: a meta-analysis. BMJ 1993;306:366–70.

75. Stephensen CB, Franchi LM, Hernandez H, et al. Adverse effects of high-dose vitamin A supplements in children hospitalized with pneumonia. Pediatrics 1998;101(5):E3 [abstract].

76. Bresee JS, Fischer M, Dowell SF, et al. Vitamin A therapy for children with respiratory syncytial virus infection: a multicenter trial in the United States. Pediatr Infect Dis J 1996;15:777–82.

77. Quinlan KP, Hayani KC. Vitamin A and respiratory syncytial virus infection. Serum levels and supplementation trial. Arch Pediatr Adolesc Med 1996;150:25–30.

78. Kjolhede CL, Chew FJ, Gadomski AM, et al. Clinical trial of vitamin A as adjuvant treatment for lower respiratory tract infections. J Pediatr 1995;126:807–12.

79. Pinnock CB, Douglas RM, Badcock NR. Vitamin A status in children who are prone to respiratory tract infections. Aust Paediatr J 1986;22:95–9.

80. Murphy S, West KP Jr, Greenough WB 3d, et al. Impact of vitamin A supplementation on the incidence of infection in elderly nursing-home residents: a randomized controlled trial. Age Ageing 1992;21:435–9.

81. Fawzi WW, Mbise R, Spiegelman D, et al. Vitamin A supplements and diarrheal and respiratory tract infections among children in Dar es Salaam, Tanzania. J Pediatr 2000;137:660–7.

82. Ross AC. Vitamin A supplementation as therapy--are the benefits disease specific? Am J Clin Nutr 1998;68:8–9 [review].

83. Fawzi WW, Mbise RL, Fataki MR, et al. Vitamin A supplementation and severity of pneumonia in children admitted to the hospital in Dar es Salaam, Tanzania. Am J Clin Nutr 1998;68:187–92.

84. American Academy of Pediatrics Committee on Infectious Diseases. Vitamin A treatment of measles. Pediatrics 1993,91:1014–5.

85. Penn ND, Purkins L, Kelleher J, et al. The effect of dietary supplementation with vitamins A, C and E on cell-mediated immune function in elderly long-stay patients: a randomized controlled trial. Age Ageing 1991;20:169–74.

86. de la Fuente M, Ferrandez MD, Burgos MS, et al. Immune function in aged women is improved by ingestion of vitamins C and E. Can J Physiol Pharmacol 1998;76:373–80.

87. Lithgow DM, Politzer WM. Vitamin A in the treatment of menorrhagia. S Afr Med J 1977;51:191–3.

88. Patty I, Benedek S, Deak G, et al. Controlled trial of vitamin A therapy in gastric ulcer. Lancet 1982;2(8303):876 [letter].

89. Patty I, Tarnok F, Simon L, et al. A comparative dynamic study of the effectiveness of gastric cytoprotection by vitamin A, De-Nol, sucralfate and ulcer healing by pirenzepine in patients with chronic gastric ulcer (a multiclinical and randomized study). Acta Physiol Hung 1984;64:379–84.

90. Molina EL, Patel JA. A to Z: vitamin A and zinc, the miracle duo. Indian J Pediatr 1996;63:427–31 [review].

91. Malvy D. Micronutrients and tropical viral infections: one aspect of pathogenic complexity in tropical medicine. Med Trop (Mars) 1999;59:442–8 [review; in French].

92. World Health Organization. Expanded programme on immunization: programme for the prevention of blindness nutrition. Joint WHO/UNICEF statement. Vitamin A for measles. Wkly Epidemiol Rec 1987;62:133–4.

93. Coutsoudis A, Broughton M, Coovadia HM. Vitamin A supplementation reduces measles morbidity in young African children: a randomized, placebo-controlled, double-blind trial. Am J Clin Nutr 1991;54:890–5.

94. Rosales FJ, Kjolhede C. A single 210-mumol oral dose of retinol does not enhance the immune response in children with measles. J Nutr 1994;124:1604–14.

95. Rahmathullah L. Effect of receiving a weekly dose of vitamin A equivalent to the recommended dietary allowances among pre school children on mortality in south India. Indian J Pediatr 1991;58:837–47.

96. Vijayaraghavan K, Rashmiah G, Suryaprakasam B, et al. Effect of massive dose of vitamin A on morbidity and mortality in Indian children. Lancet 1990;336:1342–53.

97. Glasziou PP, Mackerras DE. Vitamin A supplementation in infectious diseases: a meta-analysis. BMJ 1993;306:366–70 [review].

98. Frieden TR, Sowell AL, Henning JK, et al. Vitamin A levels and severity of measles: New York City. Am J Dis Child 1992;146:182–6.

99. Committee on Infectious Diseases, American Academy of Pediatrics. Vitamin A treatment of Measles. Pediatrics 1993;91:1014–5.

100. Coutsoudis A, Coovadia HM, Broughton M, et al. Micronutrient utilisation during measles treated with vitamin A or placebo. Int J Vitam Nutr Res 1991;61:199–204.

101. Campos FA, Flores H, Underwood BA. Effect of an infection on vitamin A status of children as measured by the relative dose response. Am J Clin Nutr 1987;46:91–4.

102. Ozsoylu S, Cemeroglu AP, Gunay M. Vitamin A for varicella. J Pediatr 1994;125:1017–8 [letter].

103. Hunt TK. Vitamin A and wound healing. J Am Acad Dermatol 1986;15:817–21 [review].

104. Hunt TK. Vitamin A and wound healing. J Am Acad Dermatol 1986;15:817–21 [review].

105. Hunt TK, Ehrlich HP, Garcia JA, et al. Effect of vitamin A on reversing the inhibitory effect of cortisone on healing of open wounds in animals and man. Ann Surg 1969;170:633–41.

106. Romney SL, Palan PR, Duttagupta C, et al. Retinoids and the prevention of cervical dysplasias. Am J Obstet Gynecol 1981;141:890–4.

107. Kligman AM, Mills OH Jr, Leyden JJ, et al. Oral vitamin A in acne vulgaris. Preliminary report. Int J Dermatol 1981;20:278–85.

108. Morgan MY, Levine JA. Alcohol and nutrition. Proc Natl Acad Sci 1988;47:85–98.

109. Chapman K, Prabhudesai M, Erdman JW. Vitamin A status of alcoholics upon admission and after two weeks of hospitalization. J Am Coll Nutr 1993;12:77–83.

110. Leo MA, Lieber CS. Alcohol, vitamin A, and beta-carotene: adverse interactions, including hepatotoxicity and carcinogenicity. Am J Clin Nutr 1999;69:1071–85 [review].

111. Chen M, Boyce W, Hsu JM. Effect of ascorbic acid on plasma alcohol clearance. J Am Coll Nutr 1990;9:185–9.

112. Rankov BG. Vitamin A and carotene concentration in serum in persons with chronic conjunctivitis and pterygium. Int J Vitam Nutr Res 1976;46:454–7 [in German].

113. Dvorak AM. Vitamin A in Crohn’s disease. Lancet 1980;i:1303–4.

114. Skogh M, Sundquist T, Tagesson C. Vitamin A in Crohn’s disease. Lancet 1980; i:766 [letter].

115. Dvorak AM. Vitamin A in Crohn’s Disease. Lancet 1980;i:1303–4 [letter].

116. Wright JP, Mee AS, Parfitt A, et al. Vitamin A therapy inpatients with Crohn’s disease. Gastroenterology 1985;88:512–4.

117. Fawzi WW, Mbise R, Spiegelman D, et al. Vitamin A supplements and diarrheal and respiratory tract infections among children in Dar es Salaam, Tanzania. J Pediatr 2000;137:660–7.

118. Frommer DJ. The healing of gastric ulcers by zinc sulphate. Med J Aust 1975;22(21):793–6.

119. Keyvani F, Yassai M, Kimiagar M. Vitamin A status and endemic goiter. Int J Vitam Nutr Res 1988;58:155–60.

120. Mesaros-Kanjski E, Kontosic I, Kusic Z, et al. Endemic goitre and plasmatic levels of vitamins A and E in the school-children on the island of Krk, Croatia. Coll Antropol 1999;23:729–36.

121. Mesaros-Kanjski E, Kontosic I, Kusic Z, et al. Endemic goitre and plasmatic levels of vitamins A and E in the school-children on the island of Krk, Croatia. Coll Antropol 1999;23:729–36.

122. Mutaku JF, Many MC, Colin I, et al. Antigoitrogenic effect of combined supplementation with dl-alpha-tocopherol, ascorbic acid and beta-carotene and of dl-alpha-tocopherol alone in the rat. J Endocrinol 1998;156:551–61.

123. Semba RD, Graham NMH, Caiaffa WT, et al. Increased mortality associated with vitamin A deficiency during human immunodeficiency virus type 1 infection. Arch Intern Med 1993;153:2149–54.

124. Semba RD, Miotti PG, Chiphangwi JD, et al. Maternal vitamin A deficiency and mother-to-child transmission of HIV-1. Lancet 1994;343:1593–7.

125. Coutsoudis A, Pillay K, Spooner E, et al. Randomized trial testing the effect of vitamin A supplementation on pregnancy outcomes and early mother-to-child HIV-1 transmission in Durban, South Africa. South African Vitamin A Study Group. AIDS 1999;13:1517–24.

126. Kennedy CM, Coutsoudis A, Kuhn L, et al. Randomized controlled trial assessing the effect of vitamin A supplementation on maternal morbidity during pregnancy and postpartum among HIV-infected women. J Acquir Immune Defic Syndr 2000;24:37–44.

127. Fawzi WW, Msamanga G, Hunter D, et al. Randomized trial of vitamin supplements in relation to vertical transmission of HIV-1 in Tanzania. J Acquir Immune Defic Syndr 2000;23:246–54.

128. Coutsoudis A, Bobat RA, Coovadia HM, et al. The effects of vitamin A supplementation on the morbidity of children born to HIV-infected women. Am J Public Health 1995;85:1076–81.

129. Hanekom WA, Yogev R, Heald LM, et al. Effect of vitamin A therapy on serologic responses and viral load changes after influenza vaccination in children infected with the human immunodeficiency virus. J Pediatr 2000;136:550–2.

130. Humphrey JH, Quinn T, Fine D, et al. Short-term effects of large-dose vitamin A supplementation on viral load and immune response in HIV-infected women. J Acquir Immune Defic Syndr Hum Retrovirol 1999;20:44–51.

131. Smolle J, Wawschinek O, Hayn H, Eber O. Vitamin A and carotene in thyroid disease. Acta Med Austriaca 1983;10:71–3 [in German].

132. Aktuna D, Buchinger W, Langsteger W, et al. Beta-carotene, vitamin A and carrier proteins in thyroid diseases. Acta Med Austriaca 1993;20:17–20 [in German].

133. Mazzotta MY. Nutrition and wound healing. J Am Podiatr Med Assoc 1994;84:456–62 [review].

134. Swartz-Basile DA, Rubin DC, Levin MS. Vitamin A status modulates intestinal adaptation after partial small bowel resection. JPEN J Parenter Enteral Nutr 2000;24:81–8.

135. Ehrlich H, Hunt TK. Effects of cortisone and vitamin A on wound healing. Ann Surg 1968;167:324–8.

136. Hunt TK, Ehrlich HP, Garcia JA, Dunphy JE. Effect of vitamin A on reversing the inhibitory effect of cortisone on healing of open wounds in animals and man. Ann Surg 1969;170:633–40.

137. Ehrlich HP, Tarver H, Hunt TK. Effects of vitamin A and glucocorticoids upon inflammation and collagen synthesis. Ann Surg 1973;177:222–7.

138. Hunt TK, Ehrlich HP, Garcia JA, Dunphy JE. Effect of vitamin A on reversing the inhibitory effect of cortisone on healing of open wounds in animals and man. Ann Surg 1969;170:633–40.

139. Hunt TK. Vitamin A and wound healing. J Am Acad Dermatol 1986;15:817–21.

140. Block E. The use of vitamin A in premenstrual tension. Acta Obstet Gynecol Scand 1960;39:586–92.

141. Argonz J, Abinzano C. Premenstrual tension treated with vitamin A. J Clin Endocrinol 1950;10:1579–89.

142. Tangney CC, Phillips G, Bell RA, et al. Selected indices of micronutrient status in adult patients with sickle cell anemia (SCA). Am J Hematol 1989;32:161–6.

143. Chiu D, Vichinsky E, Ho SL, et al. Vitamin C deficiency in patients with sickle cell anemia. Am J Pediatr Hematol Oncol 1990;12:262–7.

144. Jain SK, Ross JD, Duett J, Herbst JJ. Low plasma prealbumin and carotenoid levels in sickle cell disease patients. Am J Med Sci 1990;229:13–5.

145. Jain SK, Williams DM. Reduced levels of plasma ascorbic acid (vitamin C) in sickle cell disease patients: its possible role in the oxidant damage to sickle cells in vitro. Clin Chim Acta 1985;149:257–61.

146. Natta C, Stacewicz-Sapuntzakis M, Bhagavan H, Bowen P. Low serum levels of carotenoids in sickle cell anemia. Eur J Haematol 1988;41:131–5.

147. Essein, EU. Plasma levels of retinol, ascorbic acid and alpha-tocopherol in sickle cell anemia. Centr Afr J Med 1995;41:48–50.

148. Ndombi IO, Kinoti SN. Serum vitamin E and the sickling status in children with sickle cell anemia. East Afr Med J 1990;67:720–5.

149. Phillips G, Tangney CC. Relationship of plasma alpha tocopherol to index of clinical severity in individuals with sickle cell anemia. Am J Hematol 1992;41:227–31.

150. Natta CL, Machlin LJ, Brin M. A decrease in irreversibly sickled erythrocytes in sickle cell anemia patients given vitamin E. Am J Clin Nutr 1980;33:968–71.

151. Crary EJ, McCarty MF. Potential clinical applications for high-dose nutritional antioxidants. Med Hypotheses 1984;13:77–98.

152. Crary EJ, McCarty MF. Potential clinical applications for high-dose nutritional antioxidants. Med Hypotheses 1984;13:77–98.

153. Crary EJ, McCarty MF. Potential clinical applications for high-dose nutritional antioxidants. Med Hypotheses 1984;13:77–98.

154. Hussey GD, Klein M. A randomized, controlled trial of vitamin A in children with severe measles. N Engl J Med 1990;323:160–4.

155. Fuchs J. Potentials and limitations of the natural antioxidants RRR-alpha-tocopherol, L-ascorbic acid and beta-carotene in cutaneous photoprotection. Free Radic Biol Med 1998;25:848–73.

156. Werninghaus K, Meydani M, Bhawan J, et al. Evaluation of the photoprotective effect of oral vitamin E supplementation. Arch Dermatol 1994;130:1257–61.

157. Fuchs J, Kern H. Modulation of UV-light-induced skin inflammation by D-alpha-tocopherol and L-ascorbic acid: a clinical study using solar simulated radiation. Free Radic Biol Med 1998;25:1006–12.

158. Eberlein-Konig B, Placzek M, Przybilla B. Protective effect against sunburn of combined systemic ascorbic acid (vitamin C) and d-alpha-tocopherol (vitamin E). J Am Acad Dermatol 1998;38:45–8.

159. McArdle F, Rhodes LE, Parslew RA, et al. Effects of oral vitamin E and beta-carotene supplementation on ultraviolet radiation-induced oxidative stress in human skin. Am J Clin Nutr 2004;80:1270–5.

160. Garmyn M, Ribaya-Mercado JD, Russel RM, et al. Effect of beta-carotene supplementation on the human sunburn reaction. Exp Dermatol 1995;4:104–11.

161. Wolf C, Steiner A, Honigsmann H, et al. Do oral carotenoids protect human skin against UV erythema, psoralen phototoxicity, and UV-induced DNA damage? J Invest Dermatol 1988;90:55–57.

162. Mathews-Roth MM, Pathak MA, Parrish J, et al. A clinical trial of the effects of oral beta-carotene on the responses of human skin to solar radiation. J Invest Dermatol 1972;59:349–53.

163. Gollnick HP, Hopfenmuller W, Hemmes C, et al. Systemic B-carotene plus topical sunscreen are an optimal protection against harmful effects of natural UV-sunlight. Eur J Dermatol 1996;6:200–5.

164. Lee J, Jiang S, Levine N, Watson RR. Carotenoid supplementation reduces erythema in human skin after simulated solar radiation exposure. Proc Soc Exp Biol Med 2000;223:170–4.

165. Heinrich U, Gartner C, Wiebusch M, et al. Supplementation with beta-carotene or a similar amount of mixed carotenoids protects humans from UV-induced erythema. J Nutr 2003;133:98–101.

166. Aust O, Stahl W, Sies H, et al. Supplementation with tomato-based products increases lycopene, phytofluene, and phytoene levels in human serum and protects against UV-light-induced erythema. Int J Vitam Nutr Res 2005;75:54–60.

167. Cesarini JP, Michel L, Maurette JM, et al. Immediate effects of UV radiation on the skin: modification by an antioxidant complex containing carotenoids. Photodermatol Photoimmunol Photomed 2003;19:182–9.

168. Greul AK, Grundmann JU, Heinrich F, et al. Photoprotection of UV-irradiated human skin: an antioxidative combination of vitamins E and C, carotenoids, selenium and proanthocyanidins. Skin Pharmacol Appl Skin Physiol 2002;15:307–15.

169. La Ruche G, Cesarini JP. Protective effect of oral selenium plus copper associated with vitamin complex on sunburn cell formation in human skin. Photodermatol Photoimmunol Photomed 1991;8:232–5.

170. Sies H, Stahl W. Nutritional protection against skin damage from sunlight. Annu Rev Nutr 2004;24:173–200 [review].

171. Sies H, Stahl W. Carotenoids and UV protection. Photochem Photobiol Sci 2004;3:749-52 [review].

172. Fuchs J. Potentials and limitations of the natural antioxidants RRR-alpha-tocopherol, L-ascorbic acid and beta-carotene in cutaneous photoprotection. Free Radic Biol Med 1998;25:848–73.

173. Werninghaus K, Meydani M, Bhawan J, et al. Evaluation of the photoprotective effect of oral vitamin E supplementation. Arch Dermatol 1994;130:1257–61.

174. Fuchs J, Kern H. Modulation of UV-light-induced skin inflammation by D-alpha-tocopherol and L-ascorbic acid: a clinical study using solar simulated radiation. Free Radic Biol Med 1998;25:1006–12.

175. Eberlein-Konig B, Placzek M, Przybilla B. Protective effect against sunburn of combined systemic ascorbic acid (vitamin C) and d-alpha-tocopherol (vitamin E). J Am Acad Dermatol 1998;38:45–8.

176. McArdle F, Rhodes LE, Parslew RA, et al. Effects of oral vitamin E and beta-carotene supplementation on ultraviolet radiation-induced oxidative stress in human skin. Am J Clin Nutr 2004;80:1270–5.

177. Garmyn M, Ribaya-Mercado JD, Russel RM, et al. Effect of beta-carotene supplementation on the human sunburn reaction. Exp Dermatol 1995;4:104–11.

178. Wolf C, Steiner A, Honigsmann H, et al. Do oral carotenoids protect human skin against UV erythema, psoralen phototoxicity, and UV-induced DNA damage? J Invest Dermatol 1988;90:55–57.

179. Mathews-Roth MM, Pathak MA, Parrish J, et al. A clinical trial of the effects of oral beta-carotene on the responses of human skin to solar radiation. J Invest Dermatol 1972;59:349–53.

180. Gollnick HP, Hopfenmuller W, Hemmes C, et al. Systemic B-carotene plus topical sunscreen are an optimal protection against harmful effects of natural UV-sunlight. Eur J Dermatol 1996;6:200–5.

181. Lee J, Jiang S, Levine N, Watson RR. Carotenoid supplementation reduces erythema in human skin after simulated solar radiation exposure. Proc Soc Exp Biol Med 2000;223:170–4.

182. Heinrich U, Gartner C, Wiebusch M, et al. Supplementation with beta-carotene or a similar amount of mixed carotenoids protects humans from UV-induced erythema. J Nutr 2003;133:98–101.

183. Aust O, Stahl W, Sies H, et al. Supplementation with tomato-based products increases lycopene, phytofluene, and phytoene levels in human serum and protects against UV-light-induced erythema. Int J Vitam Nutr Res 2005;75:54–60.

184. Cesarini JP, Michel L, Maurette JM, et al. Immediate effects of UV radiation on the skin: modification by an antioxidant complex containing carotenoids. Photodermatol Photoimmunol Photomed 2003;19:182–9.

185. Greul AK, Grundmann JU, Heinrich F, et al. Photoprotection of UV-irradiated human skin: an antioxidative combination of vitamins E and C, carotenoids, selenium and proanthocyanidins. Skin Pharmacol Appl Skin Physiol 2002;15:307–15.

186. La Ruche G, Cesarini JP. Protective effect of oral selenium plus copper associated with vitamin complex on sunburn cell formation in human skin. Photodermatol Photoimmunol Photomed 1991;8:232–5.

187. Sies H, Stahl W. Nutritional protection against skin damage from sunlight. Annu Rev Nutr 2004;24:173–200 [review].

188. Sies H, Stahl W. Carotenoids and UV protection. Photochem Photobiol Sci 2004;3:749-52 [review].

189. Tyson JE, Wright LL, Oh W, et al. Vitamin A supplementation for extremely-low-birth-weight infants. N Engl J Med 1999;340:1962–8.

190. Smolle J, Wawschinek O, Hayn H, Eber O. Vitamin A and carotene in thyroid disease. Acta Med Austriaca 1983;10:71–3 [in German].

191. Aktuna D, Buchinger W, Langsteger W, et al. Beta-carotene, vitamin A and carrier proteins in thyroid diseases. Acta Med Austriaca 1993;20:17–20 [in German].

192. Polidori MC, Mecocci P, Stahl W, et al. Plasma levels of lipophilic antioxidants in very old patients with type 2 diabetes. Diabetes Metab Res Rev 2000;16:15–9.

193. Mejia LA, Chew F. Hematological effect of supplementing anemic children with vitamin A alone and in combination with iron. Am J Clin Nutr 1988;48:595–600.

194. Muñoz EC, Rosado JL, Lopez P, et al. Iron and zinc supplementation improves indicators of vitamin A status of Mexican preschoolers. Am J Clin Nutr 2000;71:789–94.

195. Rothman KJ, Moore LL, Singer MR, et al. Teratogenicity of high vitamin A intake. N Engl J Med 1995;333:1369–73.

196. Mastroiacovo P, Mazzone T, Addis A, et al. High vitamin A intake in early pregnancy and major malformations: a multicenter prospective controlled study. Teratology 1999;59:7–11.

197. Biesalski HK. Comparative assessment of the toxicology of vitamin A and retinoids in man. Toxicology 1989;57:117–61.

198. Azais-Braesco V, Pascal G. Vitamin A in pregnancy: requirements and safety limits. Am J Clin Nutr 2000;71(5 Suppl):1325S–33S [review].

199. Wiegand UW, Hartmann S, Hummler H. Safety of vitamin A: recent results. Int J Vitam Nutr Res 1998;68:411–6 [review].

200. Fawzi WW, Mbise R, Spiegelman D, et al. Vitamin A supplements and diarrheal and respiratory tract infections among children in Dar es Salaam, Tanzania. J Pediatr 2000;137:660–7.

201. Sibulesky L, Hayes KC, Pronczuk A, et al. Safety of <7500 RE (<25000 IU) vitamin A daily in adults with retinitis pigmentosa. Am J Clin Nutr 1999;69:656–63.

202. Bendich A, Langseth L. Safety of vitamin A. Am J Clin Nutr 1989;49:358–71.

203. Cartmel B, Moon TE, Levine N. Effects of long-term intake of retinol on selected clinical and laboratory indexes. Am J Clin Nutr 1999;69:937–43.

204. Melhus H, Michaelsson K, Kindmark A, et al. Excessive dietary intake of vitamin A is associated with reduced bone mineral density and increased risk for hip fracture. Ann Int Med 1998;129:770–8.

205. Binkley N, Krueger D. Hypervitaminosis A and bone. Nutr Rev 2000;58:138–44 [review].

206. Frame B, Jackson CE, Reynolds WA, Umphrey JE. Hypercalcemia and skeletal effects in chronic hypervitaminosis A. Ann Intern Med 1974;80:44–8.

207. Patel P, Hanning RM, Atkinson SA, et al. Intoxication from vitamin A in an asthmatic child. CMAJ 1988;139:755–6.

Vitamin A Benefits

Here is what people are saying about the benefits of Vitamin A.

Now Foods Vitamin A ~~$8.99~~ $4.85		"I take one a day to stop acne. It works great. ..."
Read Reviews >

Now Foods Vitamin A ~~$17.99~~ $9.71		"Now Foods lo ha vuelto a lograr! Muy alta concentración de vitamina A de origen animal (concretamente procede del hígado de pescados, y no sintético como el retinol que venden en farmacias), lo que aumenta su absorción y eficacia en el organismo. Para mí es un suplemento indispensable y lo usamos toda la familia, incluso se lo doy a los perros! Par..."
Read Reviews >

BioTech Pharmacal A-25 $7.40		"FOUND an excellent price for the best dry vitamin A on the market. As a bariatric patient with significant malabsorption, this is an amazingly easy way to supplement, as the capsules are very tiny! ..."
Read Reviews >

Now Foods Vitamin A ~~$8.99~~ $4.85		"I buy both sizes of NOW Vitamin A. It helps my skin stay smooth...."
Read Reviews >

Nutzen, Dosierung und Sicherheit von Vitamin A

Learn all about Vitamin A

Related Topics

How to take Vitamin A

Where to Find It

Possible Deficiencies