Zinc deficiency in infants and children: a review of its complex and synergistic interactions

Abstract

Zinc deficiency is estimated to contribute to over half a million deaths per year in infants and children under 5 years of age. This paper reviews the features of mild-to-moderate zinc deficiency, which include growth faltering, deficits in immune function and altered integrity and function of the gastro-intestinal tract. Sub-clinical features include oxidative stress and a pro-inflammatory state. The homeostatic response to low dietary zinc intake by increasing absorption is limited, especially if the source of zinc is of poor bioavailability, and conservation of endogenous intestinal losses is a critical component of adaptation. Owing to low zinc intakes, older breastfed infants, especially those of low birthweight, are predictably at risk of zinc deficiency if complementary food choices are unfortified and/or low in zinc. Host factors such as young age, poor intra-uterine zinc accretion owing to poor maternal status and/or prematurity, and gastro-intestinal dysfunction also potently predispose to zinc deficiency. Environmental enteropathy, which is prevalent in low-resource settings, may substantially impair zinc absorption and/or increase endogenous losses, and thus lead to relatively high zinc requirements. Emerging evidence highlights common features between chronic inflammation and zinc deficiency, and each may exacerbate the other. More investigations of zinc homeostasis in populations in low-resource settings are needed to better quantify absorption capacity and losses. Effective preventive strategies must address potentially higher zinc requirements as well as the underlying context that perpetuates a vicious cycle of zinc deficiency and multiple adverse outcomes.

Parameters Influencing Zinc in Experimental Systems in Vivo and in Vitro

“…Therefore, serum zinc seems to be the best indicator of the zinc status in a population [15,36]. The measurement of different proteins in peripheral blood cells to determine the long-term zinc status is promising, but still difficult to implement on a large scale in a clinical and especially field setting in particular [37].…”

“…Miller et al developed a mathematical model to estimate zinc absorption including basic characteristics of the intestinal biochemistry [69], and according to this model, the negative effect of phytates explains more than 80% of the variation found when measuring absorption of dietary zinc in adults [70]. However, for children, data on this effect is rare [36]. Miller et al even showed an independence between zinc absorption and phytate:zinc molar ratio in young children.…”

Determinantes dietéticos del consumo de zinc en menores de cinco años con retardo de crecimiento en comunidades mayas de Guatemala

“…Las variables estudiadas fueron: fuentes alimentarias de zinc, gramos de zinc y proteína, prácticas culinarias y La deficiencia de zinc es un problema de salud pública cuando su prevalencia supera el 20% (3) . En Guatemala, esta alcanza 34,9% e, incluso, 46,7% en algunas regiones (4) , zonas que también presentan prevalencias elevadas de RC (5) .…”

Bioaccumulation of zinc in Rana tigrina in different aquatic habitats

“…Zinc is necessary for standard growth, development and normal functions for all animal species. Death, tumor growth and some chromosomal aberrations is caused by Zinc deficit (Hrabeta et al, 2016;Krebs et al, 2014). It must be mentioned here that lead, cadmium, chromium, mercury etc.…”