Impairment of taste and olfaction in patients with cirrhosis: the role of vitamin A.

Taste and olfaction sensory modalities and the response to vitamin A replenishment were studied in 37 vitamin A deficient patients (determined by low serum levels and abnormal dark adaptation) with stable alcoholic cirrhosis. Among this group of patients, 11 also had low serum zinc levels which ranged from 45 to 63 micrograms/dl. Initial taste and olfaction mean detection thresholds for all test substances were significantly higher (less sensitive) in all patients as compared to 21 sex-matched healthy subjects of the same age range (P less than 0.05). Twenty-seven patients including the 11 patients with low serum zinc were treated with oral vitamin A (10 000 micrograms/d) for 4 weeks. Among the vitamin a deficient patients there was significant improvement following vitamin A treatment in the mean detection and mean recognition thresholds for bitter and salty taste (P less than 0.01) and for pyridine olfaction (P less than 0.05) regardless of zinc status. Improvement in taste and olfaction correlated with a reversal of serum vitamin A levels and dark adaptation toward normal. The mechanism whereby vitamin A affects specific taste and smell (ie salty and bitter taste; pyridine smell) modalities is at present unknown.