Effects of zinc metabolism upon gustatory sensitivity.

A series of experiments was conducted to investigate the relationships between zinc metabolism and gustatory sensitivity. Among hospitalized alcoholic subjects, there was an incidence of decreased taste sensitivity, both subjectively and objectively. These subjects had lower than normal plasma zinc concentration levels at the time of admission to the hospital. Without medication, there were no significant changes in taste perception of these subjects during the first two or three weeks of hospitalization. In a single-blind study of 25 alcoholic subjects, both the subjects treated with zinc sulphate at dosages of 150 mg Zn++ daily and those treated with placebos showed significant improvements in taste sensitivity to sweet, salt and bitter stimuli but not to sour stimuli during the three weeks of therapy. There were no significant differences in taste responses between the subjects in the zinc treatment and placebo groups. An exploratory study into the effects of zinc sulphate solutions, used as mouthrinses, on taste perception was also carried out; the results showed that zinc sulphate had no significant effect on the perception of sweetness of sucrose. The overall results were interpreted as contradictory to the hypothesis that zinc metabolism played a significant role in taste processes. The results were discussed in the light of previous work by Henkin and his associates, which had suggested that zinc played a crucial role in taste acuity