A Novel Method of Assessment of the Zinc Nutrition Status and Zinc Deficiency-Induced Taste Impairment

Abstract

We developed the ratio of the apo/holo activities of angiotensin-converting enzyme (ACE ratio) in the serum as an index of the zinc nutrition status. The zinc nutrition status in patients with taste impairment was estimated based on the dietary zinc intake, serum zinc concentration and the ACE ratio in the serum. The results obtained in a series of our studies suggested that zinc deficiency is the predominant factor underlying taste impairment, even when the serum zinc concentrations were within the normal range, and that the ACE ratio is a more sensitive indicator of the zinc nutrition status than the serum zinc concentration. There were no differences in the dietary intake of zinc after adjustment for the energy intake or the serum zinc concentration between patients with taste impairment and age-matched healthy subjects. On the other hand, the ACE ratio in patients with taste impairment was significantly higher than that in age-matched healthy subjects. These findings suggest that zinc deficiency in patients with taste impairment is due to malabsorption of dietary zinc from the duodenum and jejunum, and not because of low dietary intake of zinc.