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Received Feb 1, 2017; Revised Mar 13, 2017; Accepted Apr 12, 2017
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1. Introduction
Hen’s eggs have long been one of the most important foods for man because of their high nutritional value, low cost, and easy preparation [1]. It is a food that contributes to the intake of nutrients, proteins, vitamins (B1, B2, B12, niacin, biotin, choline, pantothenic acid, A, E, K, and D) and minerals (Se, K, P, I, Zn, Cu, Mn, and Fe) [2]. The nutritional value varies markedly between the yolk and the white. The fat, cholesterol, and some micronutrients are located in the yolk, while the egg white is mainly formed of water and protein. On the other hand, some minerals and water-soluble vitamins are found in higher concentrations in the yolk [3, 4].
Average consumption data for the Spanish regional areas indicate that the consumption of eggs in the Canary Islands is 31.5 g/person/day [5]. On the other hand, the average consumption recommended by the Spanish Agency for Food Safety and Nutrition (AESAN) is 24.3 g/person/day for children between the ages of 7 and 12 years and 31.2 g/person/day for adults over 17 years old [6].
Diet is an important source of metals [7], among which can be found macroelement metals (Ca, K, Na, and Mg) that are required in large quantities, which are found in greater proportion in the tissues of living beings [8].
The trace elements (Mn, Fe, Cu, Zn, Cr, Mo, and Co) are present in small quantities and are necessary for the adequate development of the physiological functions [9–14]. In the case of chromium, some institutions such as the Institute of Medicine, Food and Nutrition Board [15] or the FESNAD (Spanish Federation of Societies of Nutrition and Dietetics) [16] reported in the past that Cr (III) is an essential metal with a function in carbohydrate metabolism and in particular in maintaining normal blood glucose levels. However, a recent assessment by the European Food Safety Authority (EFSA) however highlighted that Cr is not an essential element based on insufficient proofs of a functional...