Leukemia and Vitamin A Overview

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Vitamin A is a fat-soluble vitamin, which is derived from two sources: preformed retinoids and provitamin carotenoids. Retinoids, such as retinal and retinoic acid, are found in animal sources such as livers, kidneys, eggs, and dairy produce. Carotenoids like beta-carotene (which has the highest vitamin A activity) are found in plants such as dark or yellow vegetables and carrots. The prescription drug All-Trans-Retinoic Acid (ATRA, Vesanoid®) is a vitamin A derivative that is an established treatment for acute promyelocytic leukemia and improves median survival in this disease. Treatment should be under strict medical supervision. Vitamin A supplements should not be used simultaneously with ATRA due to a risk of increased toxicity.

Vitamin A toxicity, or hypervitaminosis A, is rare in the general population. Vitamin A toxicity can occur with excessive amounts of vitamin A taken over short or long periods of time. Consequently, toxicity can be acute or chronic. An infant with acute toxicity can develop a bulging fontalle (the soft spot on the head) and symptoms similar to a brain tumor. Adults experience less specific symptoms such as headache, dizziness, fatigue, malaise, blurry vision, bone pain and swelling, nausea, and/or vomiting. Severe toxicity can lead to eye damage, high levels of calcium, and liver damage. Persons with liver disease and high alcohol intake may be at risk for hepatotoxicity from vitamin A supplementation. Smokers who consume alcohol and beta-carotene may be at an increased risk for lung cancer or cardiovascular disease. At recommended doses, vitamin A is generally considered non-toxic.