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vitamin A is stored in the liver and deficiency of the vitamin occurs only after prolonged lack of dietary intake. An early symptom of vitamin A deficiency is night blindness. Additional early symptoms include follicular hyperkeratinosis, increased susceptibility to infections and cancer, and anemia &endash;equivalent to iron- deficiency anemia. Prolonged lack of vitamin A leads to deterioration of the eye tissue through progressive keratinization (hardened cell layers) of the cornea, a condition known as xerophthalmia. The increased risk of cancer is thought to be the result of a depletion in vitamin A reserves. β-carotene is a very effective antioxidant and is suspected to reduce the risk of cancers known to be initiated by the production of free radicals. Of particular interest is the potential benefit of increased β-carotene intake to reduce the risk of lung cancer in smokers. However, caution must be exercised when increasing the intake of any of the lipid soluble vitamins. Excess accumulation of vitamin A in the liver can lead to toxicity which manifests itself as bone pain, hepatosplenomegaly (enlarged liver), nausea and diarrhea.