Vitamin A, also known as retinol, is an important vitamin that helps preserve the health of many of the body's tissues. These include the teeth, bones, skin and mucous membranes such as the mouth, nose, lips, genital area and anus. It's also important in the formation of the pigments in the retina of the eye, promoting color and low-light vision. A person taking too much vitamin A can develop vitamin A toxicity, also known as hypervitaminosis A.
Bone Pain, Blurred Vision, Drowsiness
Vitamin A toxicity can result from an acute ingestion, such as when a child accidentally takes a large amount of vitamin A supplements; or chronic toxicity resulting from taking too much vitamin A over a long period. According to Medline Plus, symptoms of vitamin A toxicity include bone pain, blurred vision, softening of the skull bones in children and infants, double vision, drowsiness and headaches. Acute toxicity can cause increased intracranial pressure, a rise in the fluid pressure inside the brain. A rash with subsequent skin peeling can also result from acute ingestion.
Joint Pain, Itching, Failure to Gain Weight
Chronic toxicity results in coarse hair, loss of eyebrow hair, dry eyes and cracked lips. The skin becomes rough to the touch. Pseudotumor cerebri, in which the pressure inside the head increases for no initially obvious reason, can also occur. Children with chronic toxicity can develop joint pain, itching, failure to gain weight, delayed growth, and inflammation of the liver and the spleen. Elderly people can develop fractures easier than normal. Babies of pregnant women taking chronic high doses of vitamin A have a higher risk of developing birth defects.
Warning
Because the liver and fatty tissues store vitamin A for a long time, vitamin A supplements aren't necessary as long as the person ingests a balanced diet that includes leafy green vegetables and fruits containing beta-carotene. If taking multivitamins, check the label. According to the National Institutes of Health, the recommended daily allowance of vitamin A for adult females is 700mcg retinol activity equivalent or RAE; for men, it's 900mcg RAE. Birth defects can also occur in pregnant women taking synthetic retinoids, which are similar to vitamin A and are used to treat acne. Women taking retinoids should discuss with their doctor the risk of these medicines if they become pregnant.
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