Iodine Biofortification of Vegetables Could Improve Iodine Supplementation Status

Abstract

Iodine is an essential trace element for both humans and animals. It is essential to produce important hormones by the thyroid gland. In most inland areas, the soils are iodine deficient and its amount is insufficient to produce agricultural crops with adequate iodine content to cover the recommended daily intake. In connection with the occurrence of iodine deficiency disorders (IDDs), it has been the subject of intensive research in the past. However, following the introduction of iodized table salt in the food industry, problems related to IDD were not solved and studies on iodine mobility and bioavailability from soils are rare even today and have remained insufficiently investigated. In many countries, mainly in Europe, the prescription rate of medicaments used to treat goiter is still high. Thus, there are a considerable amount of studies looking for alternative methods for iodine supplementation in foodstuffs among the use of iodized table salt. In most cases, the subject of these studies are agricultural crops. This mini review presents the consequences of inadequate and excess iodine intake, the current status of iodine supplementation and the most recent alternative methods of the application of iodine in agriculture and its effect on the quality of used plant species.

Joint Biofortification of Plants with Selenium and Iodine: New Field of Discoveries

“…Though neither Se nor I are essential to most known plants, they are vital for several sea microalgae species [ 10 ]. Although I compounds are transferred with aerosols to remarkable distances from the seashore, the inland regions in the world always suffer from lack of I causing global problems of I deficiency [ 11 ], which along with the wide distribution of Se-deficient soils, results in serious ecological risks.…”

“…In general, Se content in most agricultural crops, known to be non-accumulators of Se, may be increased up to 0.2–3000 mg kg −1 d.w. without growth inhibition, depending on the Se form and dose [ 12 ], as it also happens for I supplementation [ 11 ]. Considering the 80–90% water content in most vegetables and the daily Se and I requirements ( Table 2 ), such biofortification values are capable to fulfill up to 100% of the Se and I adequate consumption levels.…”

“…All these forms of Se and I are used for producing vegetables fortified either with Se or I [ 11 , 31 ].…”

Targeted knockout of the gene OsHOL1 removes methyl iodide emissions from rice plants

“…Iodine is traditionally not considered an essential element for higher plants, even if very recent studies have indicated its involvement in plant metabolism as a micronutrient 32 . Although several experiments showed how high concentrations of this element can be toxic for plants 8 , 33 , at low concentrations iodine can act as a growth enhancer, positively influencing growth and nutritional parameters 33 – 36 . It was also hypothesized that, by inducing an antioxidant response, low levels of iodine may protect plants from both biotic and abiotic stress conditions, such as salinity or heavy metals 8 , 37 .…”

“…It was also hypothesized that, by inducing an antioxidant response, low levels of iodine may protect plants from both biotic and abiotic stress conditions, such as salinity or heavy metals 8 , 37 . The impact of iodine on vegetables strongly depends on the species, the iodine form, the application method, and the properties of the substrate where plants are grown 36 , 37 . It is, however, undoubted that plants are able to take up iodine from the soil through the root system and from the air through the leaves, and that the quantity taken up is usually dependent on the amount of iodine available in the environment 8 , 37 .…”