Serum concentrations of zinc and selenium in elderly people: results in healthy nonagenarians/centenarians.

Abstract

Trace elements such as zinc (Zn) and selenium (Se) play an important role in maintaining the metabolic homeostasis in elderly people and the risk of deficiency seems to increase in proportion to the age. Zn and Se concentrations, as indices of the micronutrient status in healthy subjects over 90 years, are scarcely analyzed and could represent a model for studying the physiology of successful aging. Our aim was to investigate Zn and Se concentrations in the healthy persons over the age of 90 years. One hundred and fifty two subjects volunteered for the study. They were divided into two groups: 90 non-institutionalized nonagenarians/centenarians (91-110 years) (group A) and 62 elderly subjects (60-90 years) used for comparison (group B). Serum concentrations of Zn and Se were determined, respectively, by flame atomic absorption spectrophotometry (FAAS) and electrothermal atomic absorption spectrophotometry (ETAAS). The effect of age and sex on ion concentrations was investigated. Mean values+/-standard deviation of Zn and Se concentrations in the group A were 11.97+/-2.00 and 0.87+/-0.28 micromol/l, respectively. A significant decrease of Se and Zn values was demonstrated in group A, when compared with group B, in both males and females. However, 84.4% of the 'healthy' nonagenarians/centerians had both Zn and Se concentrations equal to or greater than the lowest values of the elderly group and only 3.3% of cases showed both Zn and Se deficiencies. Consequently, a prospective and follow-up evaluation of Zn and Se could be proposed as a good index for a correct monitoring of the micronutrient deficiencies, that could represent an early sign of disease.