| Abstract [eng] |
Relevance of the problem: Iodine and selenium are microelements important for growth and development, thyroid hormone production, immune system function and antioxidant processes. Adequate intake of these microelements with food is essential; therefore, various fortification strategies are applied, including iodized salt and selenium-enriched tea. Despite public and healthcare education about the importance of these microelements and the consequences of deficiency, insufficient iodine and selenium intake remains relevant, especially among risk groups – young children, pregnant women and individuals following plant-based diets. Geographical factors are also important, as iodine and selenium deficiency affects populations differently depending on regional soil composition and dietary habits. Objective of the work: To analyze the scientific literature and determine the importance of iodine and selenium for human body functions, the prevalence of their deficiency and prevention strategies. Objectives: 1. To determine the prevalence of iodine and selenium deficiency, risk groups and consequences for society. 2. To assess the mechanisms of action of iodine and selenium in the human body and their interaction. 3. To summarize methods for assessing iodine and selenium status in individuals and populations. 4. To determine individual and population-based prevention measures and their effectiveness. Material and methods: Scientific literature was searched in the PubMed database using English keywords and their combinations: iodine AND selenium, iodine and selenium functions, iodine deficiency, selenium deficiency, iodine AND thyroid function, selenium AND thyroid function, iodine status assessment, iodine AND pregnancy, selenium AND pregnancy, maternal iodine status, universal salt iodization, iodine fortification, iodine intake, selenium AND selenoproteins. English-language scientific articles relevant to the aim of the work were included. Guidelines on iodine and selenium intake, food composition data and Lithuanian legislation were also used. Results: In total, 53 publications meeting the criteria were included in the final literature analysis. The analyzed sources show that about 30–50% of the European population still has insufficient iodine intake. A particularly high risk is observed among vegans, whose iodine intake may be 50–70% lower than that of omnivores due to the exclusion of major iodine sources such as dairy products and seafood. The literature analysis showed an important interaction between iodine and selenium: selenium deficiency may reduce the effectiveness of iodine intake, as selenium-containing enzymes, particularly iodothyronine deiodinases, are necessary for the conversion of T4 into the active hormone T3. The most reliable population-level indicator of iodine status is urinary iodine concentration (UIC), with a median below 100 µg/L indicating iodine deficiency. Serum selenoprotein P concentration is most often used to assess selenium status. Conclusions: Iodine deficiency remains relevant in Europe, especially among pregnant women and individuals following plant-based diets. Selenium deficiency is more common in regions with low selenium content in soil. Iodine and selenium have a synergistic role in thyroid hormone metabolism. Median urinary iodine concentration is the most reliable population-level indicator of iodine status, although it is insufficient for individual assessment. Selenium status should be assessed not only by total selenium concentration but also by selenoprotein P. Universal salt iodization remains the most effective and cost-efficient population-based measure for iodine deficiency prevention, while selenium deficiency prevention may include fertilizer enrichment, selenium-enriched tea or targeted supplementation in risk groups. |
