Iodine biofortification and antioxidant capacity of lettuce: potential benefits for cultivation and human health

Abstract

Iodine is considered an essential trace element for mammals, and its deficiency is related to numerous pathologies as severe as goitre, reproductive failure, mental retardation and brain damage, among others. Currently, about 30% of the world's population are affected by this deficiency, and thus, in an attempt to ameliorate these nutritional disorders, we propose a biofortification programme with iodine by an application of different dosages and forms of this element (iodide versus iodate) in lettuce plants. In this work, a study has been made of the iodine concentration in roots and edible leaves and their influence on nutritional quality through an analysis of its antioxidant capacity. The results showed that the most appropriate application rates in hydroponic cultivation were 40 lM or lower in the form I 2 because these concentrations did not reduce biomass in the treated plants with respect to control plants and caused a foliar accumulation of this element that guarantees the viability of this type of programmes. Furthermore, these data are novel, given that the treated plants show a significant increase in antioxidant compounds after the application of iodine.

Photosynthesis and metabolism of sugars from lettuce plants (Lactuca sativa L. var. longifolia) subjected to biofortification with iodine

“…in the edible parts of crops through agronomic practices or genetic selection (White and Broadley 2005). Although iodine-biofortification programmes have so far succeeded in promoting the intake of this element through plant consumption (Cao et al 1994;Zhu et al 2003;Blasco et al 2008), none of the above works studied whether iodine biofortification influences basic plant physiological processes, such as photosynthesis.…”

Can biofortification of zinc improve the antioxidant capacity and nutritional quality of beans?

“…Ríos et al (2008) conducted a study with Se biofortification in lettuce and they observed that the treatment with 40 µM selenate was the most adequate for lettuce plants, improving the antioxidant activity and accumulation of selenium, which is important in food and consumer health. Likewise, Blasco et al (2008) mentions that biofortified lettuce plants with iodine at a dose of 40 µM under the form of I-improved biomass, antioxidant activity and mineral content of lettuce, ensuring the viability of a program biofortification.…”

Biofortificación con yodo en plantas para consumo humano

“…Por su parte Blasco et al (2008) demostraron que aplicando yodo en concentraciones ≤5.1 mg L -1 de yoduro (I -) en lechuga hidropónica se obtuvo una adecuada acumulación de yodo foliar, la cual fue de 900 µg g -1 de tejido seco, cantidad que es suficiente para cumplir la demanda diaria de consumo de yodo en humanos (150 µg día -1 ) (Charlton et al, 2013) cuando se consumen entre 17 y 200 g de tejido fresco de lechuga por semana, ya que esta concentración no excede la máxima cantidad recomendada la cual es de 2 mg por día. Sin embargo a concentraciones superiores a 5.1 mg L -1 de yoduro se presentaba una reducción significativa en la biomasa, caso que no sucedió aplicando las mismas concentraciones de yodato.…”

“…Meanwhile Blasco et al (2008) demonstrated that applying iodine concentrations ≤5.1 mg L -1 iodide (I -) in hydroponic lettuce obtained an adequate accumulation of foliar iodine, which was 900 µg -1 g dry tissue, amount that is sufficient to meet the daily demand for iodine intake in humans (150 µg day -1 ) (Charlton et al, 2013) when consumed between 17 and 200 g of fresh tissue of lettuce per week, as this concentration does not exceed the maximum recommended amount which is 2 mg per day. However at concentrations above 5.1 mg L -1 iodide a significant reduction in biomass was present, thing that did not happen applying the same concentrations of iodate.…”