A histomorphometric study of the effect of chronic vitamin A deficiency on the circumvallate papilla of the rat.

Although a deterioration of taste sensitivity is known to occur during severe vitamin A depletion, the structural changes in the taste buds themselves have not been described. Circumvallate papillae from rats deprived of vitamin A were examined histomorphometrically at intervals, and changes in the gustatory apparatus were quantitated. The cross-sectional area of the circumvallate trenches increases 30-fold because of keratin accumulation when vitamin A deficiency is extreme. After 190 days on a vitamin A-free diet, 38% of rats had no detectable taste buds and the remaining taste buds appeared atrophied. The involution of the taste buds may be the result of keratin buildup in the adjacent trench or a direct consequence of vitamin A deficiency. The atrophy of the gustatory apparatus during vitamin A deficiency and the consequent presumed loss of taste sensation may contribute to a diminished interest in food and the subsequent protein-calorie malnutrition seen in vitamin A-deficient populations.