Zinc and the nutritional status in the aged

Abstract

Objective: This study evaluated the plasmatic zinc associated to the nutritional status of 80 elderly subjects, registered at the Rehabilitation Center of Araraquara, São Paulo, Brazil, from 1998 to 1999. Methods: The 24-hour Dietary Recall and Food Frequency Questionnaire were applied and the consumption of nutrients, including mineral zinc, was calculated based on the responses. Induced Coupled Plasma Atomic Emission Spectroscopy, was used to measure plasmatic zinc levels. In addition, the following complementary data for nutrition evaluation were collected: the measurement of body weight, height, and triceps fold thickness. Results: The diet of women was found satisfactory in protein and lipids, but low in carbohydrate and energy. Men had adequate intake of energy, but with low intake of carbohydrate, and high intake of protein and lipids. The average intake of zinc by women (10.8±4.1mg/d) and men (19.7±7.2mg/d) were in accord to the recommended levels. Plasma zinc averages in women (7.2±3.5μmol/L) and men (6.5±3.8μmol/L) were lower than the reference values. No correlation between zinc intake and zinc level in the plasma was detected, but zinc level in the plasma was positively correlated to protein intake; nonetheless, this correlation was found negative respective to age. Conclusions: High intake of legumes and low intake of animal protein, associated to poor energy diets for women, apparently decreased the bioavailability of zinc in the diet. The diet of the elderly should be nutritionally controlled, in order to improve the bioavailability of micronutrients such as zinc, and to prevent or correct any deficiency by supplementation.