Iodine is a beneficial element for humans, animals and plants. This study was a comparison of the effectiveness of iodosalicylate uptake by lettuce. The experiment included two sub-blocks: organic soil and mineral soil with the addition of the same fertigation of plants (8 times every 7 days) with 10 µM solutions (100 mL/per one plant/one application) of potassium iodate (KIO₃), salicylic acid (SA) alone or together with KIO₃, 5-iodosalicylic acid (5-ISA) or 3,5-diiodosalicylic acid (3,5-diISA). None of the tested iodine compounds negatively affected the yield of lettuce. When growing plants on mineral soil, plants accumulated more iodine in the leaves than plants grown on peat substrate. The use of 5-ISA allowed for achieving better efficiency of plant biofortification in iodine than the application of KIO₃ and 3,5-diISA. The type of soil significantly modified the chemical composition of lettuce.

Iodine deficiency impacts on the development of thyroid disease. Vegetables and fruits usually have a low iodine content; hence, it makes sense to increase their iodine content. Potato is consumed daily by millions of consumers and would, therefore, be a good target for biofortification with iodine programs. The aim of this study was to determine the effects of biofortification via the application of soil solutions of two iodoquinolines [8-hydroxy-7-iodo-5-quinolinic acid (8-OH-7-I-5QSA) and 5-chloro-7-iodo-8-quinoline (5-Cl-7-I-8-Q)] and KIO₃ (as an iodine positive control) on the iodine content and basic chemical composition, macro and micronutrient content, nitrogen compounds, vitamin C, and antioxidant potential of potato tubers Solanum tuberosum L. The biofortification process had no significant effect on the tuber weight in yield. The application of I in forms of KIO₃, 8-OH-7-I-5QSA, 5-Cl-7-I-8-Q resulted in an increase in the I content of tubers (1400.15; 693.65; 502.79, respectively, compared with control, 24.96 µg·kg⁻¹ d.w.). This also resulted in a decrease in elements that are harmful to consumers, such as: Al, Ni, Cr, Ag, Pb and Tl. The enrichment of tubers with 8-OH-7-I-5QSA and 5-Cl-7-I-8-Q resulted in a significant reduction in the content of ammonium ions (from 19.16 to 14.96; 13.52 mg∙kg⁻¹ f.w.) and chlorides (from 423.59 to 264.92; 265.31 mg∙kg⁻¹ f.w.). Biofortification with 8-OH-7-I-5QSA improved the polyphenolic profile of the potato tuber from 197.31 to 233.33 mg GAE·100 g⁻¹ f.w. A significant reduction in the carotenoid content of tubers after the enrichment of the plant with iodine in KIO₃, 8-OH-7-I-5QSA and 5-Cl-7-I-8-Q (from 3.46 to 2.96, 2.45, and 1.47 mg∙100 g⁻¹ d.w., respectively) was observed. It can be postulated that the production of potatoes enriched with iodoquinolines and/or KIO₃ is worthwhile, as it can provide a good source of I in the diet and simultaneously reduce the risk of developing deficiencies.

Many disorders are a result of an inadequate supply of macronutrients and micronutrients in the diet. One such element is iodine. This study used curly kale (Brassica oleracea var. Sabellica L.) biofortified with the 5,7-diiodo-8-quinolinol iodine compound. The effect of the heat treatment on the chemical composition of the curly kale was studied. In addition, iodine bioavailability was evaluated in in vivo studies. Our investigation showed that iodine loss depends on the type of heat treatment as well as on the variety of kale. Curly kale biofortified with iodoquinoline had significantly higher iodine levels after thermal processing (steaming, blanching, boiling) than the vegetable biofortified with KIO₃. Generally, steaming was the best thermal processing method, as it contributed to the lowest iodine loss in curly kale. The red variety of kale, ‘Redbor F₁’, showed a better iodine stability during the heat treatment than the green variety, ‘Oldenbor F₁’. The thermal treatment also significantly affected the dry matter content and the basic chemical composition of the tested varieties of the 5,7-diI-8-Q biofortified kale. The steaming process caused a significant increase in total carbohydrates, fiber, protein and crude fat content (‘Oldenbor F₁’, ‘Redbor F₁’), and antioxidant activity (‘Oldenbor F₁’). On the other hand, boiling caused a significant decrease, while steaming caused a significant increase, in protein and dry matter content (‘Oldenbor F₁’, ‘Redbor F₁’). The blanching process caused the smallest significant decrease in ash compared to the other thermal processes used (‘Oldenbor F₁’). A feeding experiment using Wistar rats showed that iodine from the 5,7-diI-8-Q biofortified kale has a higher bioavailability than that from the AIN-93G diet. A number of promising results have been obtained, which could form the basis for further research.

Iodine (I) is considered a beneficial element or even micronutrient for plants. The aim of this study was to determine the molecular and physiological processes of uptake, transport, and metabolism of I applied to lettuce plants. KIO₃, KIO₃ + salicylic acid, 5-iodosalicylic acid and 3,5-diiodosalicylic acid were applied. RNA-sequencing was executed using 18 cDNA libraries constructed separately for leaves and roots from KIO₃, SA and control plants. De novo transcriptome assembly generated 1937.76 million sequence reads resulting in 27,163 transcripts with N50 of 1638 bp. 329 differentially expressed genes (DEGs) in roots were detected after application of KIO₃, out of which 252 genes were up-regulated, and 77 were down-regulated. In leaves, 9 genes revealed differential expression pattern. DEGs analysis indicated its involvement in such metabolic pathways and processes as: chloride transmembrane transport, phenylpropanoid metabolism, positive regulation of defense response and leaf abscission, and also ubiquinone and other terpenoid-quinone biosynthesis, protein processing in endoplasmic reticulum, circadian rhythm including flowering induction as well as a putative PDTHA (i.e. Plant Derived Thyroid Hormone Analogs) metabolic pathway. qRT-PCR of selected genes suggested their participation in the transport and metabolism of iodine compounds, biosynthesis of primary and secondary metabolites, PDTHA pathway and flowering induction.

Iodine deficiency in the diet globally continues to be a cause of many diseases and disabilities. Kale is a vegetable that has health-promoting potential because of many nutrients and bioactive compounds (ascorbic acid, carotenoids, glucosinolates and phenolic compounds). Brassica vegetables, including kale, have been strongly recommended as dietary adjuvants for improving health. The nutrient and health-promoting compounds in kale are significantly affected by thermal treatments. Changes in phytochemicals upon such activities may result from two contrary phenomena: breakdown of nutrients and bioactive compounds and a matrix softening effect, which increases the extractability of phytochemicals, which may be especially significant in the case of iodine-fortified kale. This study investigated changes of basic composition, iodine, vitamin C, total carotenoids and polyphenols contents as well as antioxidant activity caused by steaming, blanching and boiling processes in the levels of two cultivars of kale (green and red) non-biofortified and biofortified via the application to nutrient solutions in hydroponic of two iodoquinolines [8-hydroxy-7-iodo-5-quinolinesulfonic acid (8-OH-7-I-5QSA) and 5-chloro-7-iodo-8-quinoline (5-Cl-7-I-8-Q)] and KIO₃. Thermal processes generally significantly reduced the content of the components in question and the antioxidant activity of kale, regardless of cultivar and enrichment. It was observed that the red cultivar of kale had a greater ability to accumulate and reduce iodine losses during the culinary processes. 8-hydroxy-7-iodo-5-quinolinesulfonic acid showed a protective effect against the treatments used, compared to other enrichments, thus contributing to the preservation of high iodine content.

Iodine is a key micronutrient essential for the synthesis of thyroid hormone, which regulates metabolic processes and maintains overall health. Despite its importance, iodine deficiency is a global health issue, leading to disorders such as goiter, hypothyroidism, and developmental abnormalities. Biofortification of crops with iodine is a promising strategy to enhance the dietary iodine intake, providing an alternative to iodized salt. Curly kale (Brassica oleracea var. sabellica) is a nutrient-rich vegetable high in vitamins A, C, K; minerals; fiber; and bioactive compounds with antioxidant, anti-inflammatory, and detoxifying properties. This study evaluates the effects of diets containing iodine-biofortified curly kale (‘Oldenbor F₁’ and ‘Redbor F₁’) on iodine content, tissue iodine levels, and various biochemical parameters in laboratory rats. The biofortified curly kale was enriched with 5,7-diiodo-8-quinolinol. The iodine content in the AIN-93G (control) diet and the non-biofortified curly kale diets did not differ significantly. However, diets with 5,7-diiodo-8-quinolinol biofortified kale showed significantly higher iodine levels compared with the control diets. Tissue analysis revealed the highest iodine concentrations in the liver and kidneys of rats fed diets with biofortified curly kale, indicating better iodine bioavailability. Biochemical analysis showed that rats fed the biofortified kale diet had lower total cholesterol (TC) and triglyceride (TG) levels compared with rats fed the control diet. Additionally, the biofortified diet improved the liver function markers (ALAT, ASAT) and reduced oxidative stress markers (TBARS). The study also investigated the expression of thyroid-related genes (Slc5A5, Tpo, Dio1, Dio2) in response to diets containing biofortified kale. The results demonstrated significant changes in gene expression, indicating adaptive mechanisms to dietary iodine levels and the presence of bioactive compounds in the biofortified kale. The study also observed variations in uric acid levels, with lower concentrations in rats fed a diet with biofortified curly kale. Biofortified curly kale supports thyroid function and improves liver and kidney health by reducing oxidative stress and modulating key biochemical and genetic markers. These findings suggest that biofortified curly kale can effectively increase dietary iodine intake as a nutritional intervention to address iodine deficiency and promote overall health.