New aspects of the tolerance of retinol in humans
Körner, W.F.; Völlm, J.
International Journal for Vitamin and Nutrition Research. Internationale Zeitschrift für Vitamin- und Ernahrungsforschung. Journal International de Vitaminologie et de Nutrition 45(4): 363-372
1975
ISSN/ISBN: 0300-9831 PMID: 1213862 Document Number: 92107
A total of 517 cases of reported vitamin A intoxication were reviewed and classified as acute or chronic. The acute form included a high proportion of infants 1 month to 3 years old treated with prophylactic preparations (now abandoned) containing excessive amounts of vitamin A. The etiology of chronic hypervitaminosis A was considered in more detail; 71 of 132 cases were positively identified, divided almost equally between those of vitamin A prescription and self-medication. Daily intakes and approximate total amounts ingested were compared and an estimate was made of the total storage capacity of the human liver. For comparable doses of active ingredient, symptoms occurred more rapidly after intake of emulsified preparations because they are absorbed more rapidly. Symptoms appear when the vitamin A content of the liver is in excess of 10 000 IU/g, or about 10 times the normal value. Guidelines are given for safe therapeutic administration of vitamin A, according to which a dose of 5000 IU/kg bodyweight should not be exceeded for more than 200 days.