A Historical Review of Progress in the Assessment of Dietary Zinc Intake as an Indicator of Population Zinc Status

Abstract

Dietary components influencing zinc (Zn) bioavailability were implicated in the first cases of human Zn deficiency in the Middle East in the 1960s. It was not until the 1980s that isotope tracer studies in humans quantified the effects of the type and/or quantity of Zn, protein, iron, and phytate (myo-inositol hexaphosphate) on Zn absorption in humans and confirmed the dose-dependent inhibitory effect of phytate on Zn absorption. This led to further analysis of the Zn and phytate content of foods. The use of phytate-to-Zn molar ratios as likely estimates of absorbable dietary Zn followed together with an assessment of their relationship with Zn biomarkers in low-income countries (LIC). In the 1990s, increasing knowledge of factors governing Zn-absorption diets led to refinements of Zn requirements and algorithms to estimate dietary Zn bioavailability. Their use highlighted that inadequate Zn intake from plant-based diets were a major etiological factor in morbidity and stunting in LIC, prompting the need to identify indicators of the population's Zn status. Major advances in analyses of dietary data pioneered by Beaton in 1980s led to the endorsement in 2007 of a dietary Zn indicator based on the prevalence of the population with usual Zn intake below the estimated average requirement for Zn. Risk of Zn deficiency is a public health concern when the prevalence of inadequate Zn intake is >25%. Recent findings that Zn bioavailability from high-phytate, whole-day diets is lower than previous estimates suggest that revision of Zn estimated average requirement for LIC may be warranted.

Parameters Influencing Zinc in Experimental Systems in Vivo and in Vitro

“…However, the utilization of zinc from composited meals is altered by various substances. Meanwhile, it is commonly known that phytates (e.g., in corn, soy beans, legumes and whole wheat bread) notably reduce the intestinal zinc resorption [67,68], whereupon this effect is just elicited by inositol hexa-and pentaphosphates. Lower phosphates induce no effect, or at least a lower one [67].…”

Deficiencia de micronutrientes y enfermedad celíaca en pediatría

“…Las recomendaciones de Zn incluyen un aumento para poblaciones con esas alimentaciones, en especial ante dietas con una relación molar fitatos/Zn > 15:1. Así, en niños y adolescentes, sus requerimientos pueden aumentar hasta 12-15 mg diarios, algo difícil de lograr en esas comunidades; 21 un niño con EC en ellas tiene, por lo tanto, más riesgo de presentar deficiencia de Zn y de mayor gravedad. Con esta base, la deficiencia de Zn ha sido comunicada desde hace décadas en grupos significativos de celíacos, tanto niños como adultos, incluso en las formas silentes.…”

Can Andean potatoes be agronomically biofortified with iron and zinc fertilizers?

“…It has been estimated that more than 60 % of the world's population are iron (Fe) dietary deficient and more than 30 % are zinc (Zn) dietary deficient ). Iron deficiency leads to anemia, reduces physical growth and cognitive development in young children, and is estimated to be responsible for a large proportion of the world's maternal deaths (Gibson 2012). Zinc affects multiple aspects of the human immune system and is critical to the function of more than 300 biological enzymes (McCall et al 2000).…”