Vitamin A overdose can occur if a person consumes at least twice the recommended daily dosage of vitamin A for a significant and sustained period of time. Overdose can also occur if an extremely high dose is consumed over a short span of time. The best way to treat this potentially serious overdose is to stop taking vitamin A supplements, which helps the body to clear itself of the toxicity over time, and to contact your doctor or a poison control center. Severe cases may require treatment with intravenous fluids.
Symptoms of a vitamin A overdose can include nausea, vomiting, stomach upset, diarrhea, joint pain, insomnia or trouble sleeping, confusion, loss of appetite, and headache. If the vomiting and diarrhea trigger dehydration, intravenous fluids will also be needed to help the body recover. A doctor may also prescribe medication to help the body shed the toxicity more quickly.
Left unchecked, excessive consumption of A vitamins may cause skin dryness and hair loss, liver function loss, hypertension, and brittle bones or arrested bone growth. Pregnant women are advised to closely monitor their intake of vitamin A, because large doses have been linked to birth defects. One of the most telling signs of a vitamin A overdose is yellow or orange skin, which results when there is too much of the vitamin in the body to be absorbed or metabolized efficiently.
While it is typically difficult to ingest enough vitamin A to cause vitamin poisoning, athletes with specialized dietary regimens and people with anorexia nervosa and other eating disorders may be more at risk. If you are concerned that you or someone else is at risk for vitamin A overdose, visit a doctor to rule out other possible diagnoses. A doctor can determine if your level of toxicity is too high and will recommend a course of treatment that likely includes reducing your vitamin A intake.
The vitamin A family includes a large class of fat-soluble vitamins, including retinol. It occurs most commonly in natural sources such as orange fruits and vegetables, especially carrots, and in animal sources such as fish oil. Because it can contribute to healthy functioning of the body, it is considered an essential nutrient and is included in many dietary supplements. It is so common in a healthy diet that many people easily exceed the recommended daily dosage, but few people will consume enough to cause an overdose. There have been rare reports of vitamin A overdose from people eating animal livers — including polar bear, seal, and walrus liver — that contain extremely high doses of the vitamin.
Vitamins in the A family are sometimes prescribed — often in levels above the recommended daily allowance — to promote healthier skin or teeth. Vitamin A also is a key ingredient in some acne medications, though dermatologists prescribing medications containing vitamin A are typically careful to monitor the patient for signs of overdose. The vitamin also has been linked to healthy eye function, and doctors may recommend that people whose diets lack sufficient qualities of fat-dissolved oils take a vitamin A supplement to strengthen their eyesight, particularly night vision; this is particularly true of people following a vegetarian or vegan diet.