de zinc se puede originar como resultado de una ingesta dietética inadecuada, especialmente en periodos que aumentan los requerimientos, como en periodos de crecimiento rápido (infancia y adolescencia), por malabsorción, por el incremento de las pérdidas y/o por impedimentosd en su utilización (1). Sin embargo, en la mayoría de los casos la causa primaria de deficiencia de zinc es una ingesta inadecuada del zinc absorbible, la cual comúnmente ocurre como resultado de la combinación de una baja ingesta dietética y el consumo frecuente de alimentos con bajo contenido de este elemento y/o de formas de zinc poco absorbibles (1).Se ha estimado que aproximadamente un tercio de la población mundial vive en países identificados por tener un alto riesgo de deficiencia de zinc (2) (figura 1). Los grupos que se encuentran en alto riesgo de ser deficientes en zinc son: a) lactantes nacidos pre-término, b) lactantes pequeños para su edad gestacional, c) los niños en la etapa de destete, d) los niños en recuperación de una desnutrición, e) los adolescentes, f) las mujeres ABSTRACT Zinc is a divalent cation with multiple functions in the human body. Zinc absorption occurs in the small intestine and is, together with its excretion via faeces, the point of control for zinc homeostasis. Zinc is an essential nutrient with a specific role in more than 300 enzymes which participate in all important biochemical reactions of the human body. Therefore, zinc status has a direct effect in growth, neurological and behavioural development and in the immune system. The diagnosis of zinc deficiency in individuals is not yet possible given that there still is no indicator with adequate sensitivity. Nevertheless, it is acceptable to use serum zinc levels to evaluate populations. Finally, intervention strategies such as supplementation, food fortification and/or dietary modification can be used to control and/or prevent zinc deficiency.

Helicobacter pylori infection could impair iron absorption from fortified products. The objective of the study was to determine the effect of H. pylori infection on iron absorption from asymptomatic adults consuming wheat flour fortified with iron and zinc. The (13)C urea breath test was used to assess H. pylori infection. Twenty-four H. pylori-positive and 26 H. pylori-negative volunteers completed the study. On day 1, the subjects were randomized to receive for breakfast bread fortified with either ferrous sulfate and zinc sulfate or ferrous fumarate and zinc oxide. Bread fortified with ferrous sulfate was labeled with (59)Fe as sulfate, and bread fortified with ferrous fumarate was labeled with (55)Fe as fumarate. On day 3, they received the other type of bread, with the respective tracers. On days 18-23, a proton pump inhibitor was administered to all subjects. On day 24, all subjects received bread fortified with ferrous fumarate and zinc oxide labeled with (55)Fe as fumarate. H. pylori prevalence was 77.6%. The geometric mean (±1 SD) of iron absorption was significantly higher for ferrous sulfate than fumarate (6.9 ± 2.9% vs. 0.5 ± 3.5%, p < 0.001). The H. pylori-negative subjects absorbed significantly more iron from bread fortified with either ferrous sulfate (10.5 ± 3.1% vs. 4.4 ± 2.2%, p < 0.001) or ferrous fumarate (0.6 ± 3.9% vs. 0.4 ± 3.1%, p < 0.001). Iron absorption was not significantly different between groups after administration of a proton pump inhibitor (0.3 ± 3.3% vs. 0.3 ± 2.7%, p = 0.11). H. pylori infection has a negative effect on iron absorption in asymptomatic adults consuming iron- and zinc-fortified wheat flour.

ZINC COMO NUTRIENTE EN HUMANOS La importancia del zinc como un nutriente esencial para la salud humana es de amplio conocimiento. A comienzos de la década de 1930 estudios en animales mostraron la importancia del zinc en el crecimiento y supervivencia de los animales (1). Más adelante, en 1961, Prasad y colaboradores reconocieron la importancia de la deficiencia de zinc en humanos (2). Ahora se conoce que más de 100 enzimas necesitan zinc para su función catalítica. A diferencia de otros elementos traza, se pueden encontrar ejemplos de enzimas que requieren zinc en las seis clases de enzimas (oxidoreductasas, transferasas, hidrolasas, lisasas, isomerasas y ligasas) (3). Por ende, el zinc participa en una gama de procesos bioquímicos relacionados con el metabolismo humano y no es extraño que múltiples funciones fisiológicas y metabólicas se vean alteradas cuando ocurre su deficiencia. El zinc tiene funciones catalíticas, estructurales y reguladoras. La anhidrasa carbónica, carboxipeptidasas, fosfatasa alcalina y la β-lactamasa son algunas enzimas en las que el rol catalítico del zinc es necesario para su función biológica. En su rol estructural el zinc estabiliza

IntroductionMicronutrient deficiencies and Helicobacter pylori (HP) infection are prevalent and co‐exist in several countries.ObjectiveThe objective of the study was to determine the effect of HP on iron absorption in asymptomatic adults consuming iron and zinc fortified wheat.Materials/MethodsHP was assessed using the C13‐urea breath test. On day 1 subjects received for breakfast bread fortified, per Kg flour, with either 55 mg ferrous sulfate and 60 mg zinc sulfate, labeled with 59Fe, as sulfate, or same amounts of ferrous fumarate and zinc oxide, labeled with 55Fe, as fumarate. On day 3 they received the other type of bread. On day 17 blood (20 ml) was drawn to assess circulating radioactivity. Iron absorption was determined using Eakins and Brown's double isotopic technique.Results/FindingsPrevalence of HP was 78%. Fourteen HP negative and 16 HP positive individuals completed absorption studies. There were no significant differences in the mean iron absorption of either ferrous sulfate or ferrous fumarate by infection status.ConclusionHP has no effect on iron absorption in asymptomatic adults consuming iron and zinc fortified wheat.Support by FONDECYT grant 1080032