A review is given of the evaluation of 517 cases of acute
vitamin A intoxication and chronic
hypervitaminosis A. Whereas acute
vitamin A intoxication has lost numerical importance during the past 15 years, chronic
hypervitaminosis-A, especially that caused by
self-medication, has provoked world-wide discussion concerning the safety of
retinol intake. Evaluation of the 132 cases of chronic
hypervitaminosis-A showed that approximately one quarter cannot be considered as genuine cases, whereas the rest is divided almost equally between
vitamin A prescription and
self-medication. A significant positive correlation could be shown between the dose administered and the
duration of treatment. Moreover, with comparable doses the symptoms of chronic
hypervitaminosis-A appear significantly earlier (by
a factor of 6) after emulsified or equivalent preparations than after oily
emulsions because of their better absorbability. As soon as the liver
vitamin A storage capacity is exhausted,
hypervitaminosis-A symptoms appear and the liver
vitamin A concentration is at least 10-fold the normal. The calculated
vitamin A concentration in the liver of the individual cases of
hypervitaminosis-A is highly correlated with the daily intake of
vitamin A per kg of
body-weight and its duration.