Daily tolerable upper level Treatment Stopping high vitamin A intake is the standard treatment. Most people fully recover. Phosphatidylcholine (in the form of PPC or DLPC), the substrate for lecithin retinol acyltransferase, which converts retinol into retinyl esters (the storage forms of vitamin A). Vitamin E may alleviate hypervitaminosis A. Liver transplantation may be a valid option if no improvement occurs. If liver damage has progressed into fibrosis, synthesizing capacity is compromised and supplementation can replenish PC. However, recovery is dependent on removing the causative agent: halting high vitamin A intake. History Vitamin A toxicity is known to be an ancient phenomenon; fossilized skeletal remains of early humans suggest bone abnormalities may have been caused by hypervitaminosis A. There are two theories for hypervitaminosis A in the isolated case of KMN-ER 1808. One of these is the increased consumption of meat and the second is an increase in insect consumption, or entomophagy. Vitamin A toxicity has long been known to the Inuit as they will not eat the liver of polar bears or bearded seals due to them containing dangerous amounts of Vitamin A. It has been known to Europeans since at least 1597 when Gerrit de Veer wrote in his diary that, while taking refuge in the winter in Nova Zemlya, he and his men became severely ill after eating polar bear liver. In 1913, Antarctic explorers Douglas Mawson and Xavier Mertz were both poisoned (and Mertz died) from eating the livers of their sled dogs during the Far Eastern Party. Another study suggests, however, that exhaustion and diet change are more likely to have caused the tragedy. Other animals Some Arctic animals demonstrate no signs of hypervitaminosis A despite having 10–20 times the level of vitamin A in their livers as other Arctic animals. These animals are top predators and include the polar bear, Arctic fox, bearded seal, and glaucous gull. This ability to efficiently store higher amounts of vitamin A may have contributed to their survival in the extreme environment of the Arctic. Treatment These treatments have been used to help treat or manage toxicity in animals. Although not considered part of standard treatment, they might be of some benefit to humans. Vitamin E appears to be an effective treatment in rabbits, and prevents side effects in chicks Taurine significantly reduces toxic effects in rats. Retinoids can be conjugated by taurine and other substances. Significant amounts of