Ja övedoser av A-vitamin är farligt för levern.. och sådant får man om man äter rå isbjörnslever elelr medeciner som innehåller högdos.. används mest mot svår acne.

Du lär alldrig kunna äta vanlig lever eller morötter i den mängd att giftverkan uppstår.

http://sv.wikipedia.org/wiki/A-vitamin

Morötter är ingen användbar källa. Får att få i oss a-vitamin är det animalier som gäller.

"Hypervitaminosis A occurs when the maximum limit for liver stores of retinoids is exceeded. The excess vitamin A enters the circulation causing systemic toxicity. Betacarotene, a precursor form of vitamin A typical of vegetable sources such as carrots, is selectively converted into retinoids, so it does not cause toxicity; however, overconsumption can cause carotenosis, a benign condition in which the skin turns orange.

Although hypervitaminosis A can occur when large amounts of liver (including cod liver oil and other fish oils) are regularly consumed, most cases of vitamin A toxicity result from an excess intake of vitamin A in the form of vitamin supplements. Toxic symptoms can also arise after consuming very large amounts of preformed vitamin A over a short period of time. (See Polar-bear liver below.) The U.S.Institute of Medicine says that the Lowest Observed Adverse Effect Level (LOAEL) for vitamin A, when taken over an extended period of time is 21,600 IU.[7] Most multivitamins contain vitamin A doses below 10,000 IU, therefore multi-vitamins are unlikely to cause vitamin A toxicity when taken at their recommended dosages. But in high doses, its central nervous system toxicity can be enhanced by itslipid solubility because it is readily transported across the blood brain barrier and concentrated in the brain.[citation needed]

Vitamin A causes cells to swell with fluid; too much vitamin A causes them to rupture in hyposmotic environments, hence the toxicity. Toxicity has been shown to be mitigated through vitamin E (tocopherol), cholesterol, zinc, taurine, and calcium.[8] Cholesterol has been shown to prevent retinol induced golgi fragmentation.

http://en.wikipedia.org/wiki/Hypervitaminosis_A