Effect of iodine concentration on growth, iodine uptake and antioxidant activityof lettuce (Lactuca sativa L.) biofortified with iodine in nutrient film techniquehydroponic system

According to the National Iodine Deficiency Disorder (IDD), 48.2% of primary school children aged 8 to 10 years have deficiencies in iodine. In fact, a shortage of iodine is one of the causes of goitre problems in 2.1% of youngsters. Furthermore, pregnant women and school pupils have lower than ideal iodine levels. The iodine biofortification of vegetables provides an excellent opportunity to boost human iodine intake. The study conducted at the Plant Factory, Horticulture Research Centre, MARDI aimed to investigate the effect of potassium iodide (KI) on the growth, iodine uptake and antioxidant activity of butterhead lettuce grown in a nutrient film technique (NFT) hydroponic system. The study used different doses of KI (0, 1, 5, 7, 13 and 26 mg/L) for the biofortification of lettuce with iodine. The results of the study showed that the application of 5 mg/L of KI significantly increased the biomass, leaf area, phenolic content, and antioxidant capacity of butterhead lettuce. Additionally, application of KI less than 7 mg/L increased iodine content without toxicity effects on plants. This indicates that the biofortification of lettuce with iodine is easily applicable in a hydroponic growing system and can significantly improve the nutritional quality of the crop. One of the major implications of this study is that the iodine biofortification of vegetables, such as lettuce, can provide an excellent opportunity to boost human iodine intake. The study found that 1 g of iodine-biofortified lettuce would provide 60%, 46%, and 30% of the recommended daily allowance of iodine for children, pregnant women, and adolescents, respectively.