Quick look on internet May 2010
Vitamin A toxicity can be acute (usually due to accidental ingestion by children) or chronic. Both types usually cause headache and increased intracranial pressure. Acute toxicity also causes nausea and vomiting. Chronic toxicity also causes changes in skin, hair, and nails; abnormal liver test results; and, in a fetus, birth defects. Diagnosis is usually clinical. Unless birth defects are present, adjusting the dose almost always leads to complete recovery.
Acute vitamin A toxicity in children may result from taking large doses (> 300,000 IU >100,000 RAE), usually accidentally. In adults, acute toxicity has occurred when arctic explorers ingested polar bear or seal livers, which contain several million units of vitamin A.
Chronic toxicity in older children and adults usually develops after doses of > 30,000 RAE (> 100,000 IU)/day have been taken for months. Megavitamin therapy is a possible cause, as are massive daily doses (50,000 to 120,000 RAE 150,000 to 350,000 IU) of vitamin A or its metabolites, which are sometimes given for nodular acne or other skin disorders. Adults who consume > 1500 RAE (> 4500 IU)/day of vitamin A may develop osteoporosis. Infants who are given excessive doses (6,000 to 20,000 RAE 18,000 to 60,000 IU/day) of water-miscible vitamin A may develop toxicity within a few weeks.
Following is from http://emedicine.medscape.com/article/126104-overview
* Mortality is rare from vitamin A toxicity.
* Morbidity is evident by the wide range of complications observed in this condition.
- In acute vitamin A toxicity, a history of some or all of the following may be obtained:
* Altered mental status
* Abdominal pain
* Blurred vision
* Muscle pain with weakness
- In chronic vitamin A toxicity, a history of some or all of the following may be obtained:
* Hair loss
* Dryness of mucus membranes
* Fissures of the lips
* Weight loss
* Bone fracture4
* Bone and joint pains
* Menstrual abnormalities
The 2007 Annual Report of the American Association of Poison Control Centers' National Poison Data System document the total number of exposures for each class of vitamins, the number of patients with major adverse outcomes, and the number of fatalities from that ingestion,3 as follows:
* Adult multiple vitamins without iron or fluoride - 3,000 total exposures, 3 major outcomes, and 0 deaths
* Adult multiple vitamins with iron but without fluoride - 7798 total exposures, 2 major outcomes, and 0 deaths
* Pediatric multiple vitamins without iron or fluoride - 20,774 total exposures, 0 major outcomes, and 0 deaths
* Pediatric multiple vitamins with iron but without fluoride - 15,407 total exposures, 0 major outcome, and 0 deaths
* Vitamin A - 550 total exposures, 0 major outcomes, and 0 deaths
* Niacin - 2,303 total exposures, 4 major outcomes, and 0 deaths
* Pyridoxine - 212 total exposures, 0 major outcomes, and 0 deaths
* Other B complex vitamins - 2,546 total exposures, 3 major outcomes, and 0 deaths
* Vitamin C - 1,531 total exposures, 2 major outcomes, and 0 deaths
* Vitamin D - 596 total exposures, 1 major outcome, and 0 deaths
* Vitamin E - 740 total exposures, 0 major outcome, and 0 deaths
* Overall, 58,622 exposures to different types of vitamins were reported to the poison control centers across the United States in 2007, accounting for 17 major adverse outcomes and 1 death. Of the total exposures, 45,498 incidents occurred in children younger than 6 years old and 7,693 involved individuals aged 6-19 years.
The 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.
The Institute of Medicine has established Daily Tolerable Upper Levels (UL) of intake for vitamin A from supplements that apply to healthy populations, in order to help prevent the risk of vitamin A toxicity. These levels for preformed vitamin A in micrograms (µg) and International Units (IU) are
* 0-3 years: 600 µg or 2000 IU
* 4-8 years: 900 µg or 3000 IU
* 9-13 years: 1700 µg or 5665 IU
* 14-18 years: 2800 µg or 9335 IU
* 19+ years: 3000 µg or 10,000 IU