[Iodine supply of pregnant women in the Czech Republic]. / Zásobení jodem u tehotných zen v Ceské republice.

INTRODUCTION: Iodine deficiency is a global public health problem which is particularly noticeable in pregnant or breastfeeding women and their children. Even mild iodine deficiency during pregnancy can lead to damage to the developing brain and thus affecting the fetus intelligence, his cognitive and neurological function, embryogenesis and growth. PATIENTS: In the period 2010-2015 was determined by spectrophotometry at the Institute of Endocrinology the basal urinary iodine in 532 pregnant women at the age of 32 ± 5 (18-44) years, which came from Prague, Hradec Kralove and Mlada Boleslav. It was located 349 women in the first trimester, 112 in the second trimester, and 71 women in the third trimester. In the monitoring of pregnant women in the first trimester 218 basal urine samples of women were determined by mass spectrometry with inductively coupled plasma (ICP MS) in The National Institute of Public Health (NIPH). Women came from the 6 areas in the Czech Republic. Development of urinary iodine in the general population in the period 1994-2015 was observed in patients who underwent Institute of Endocrinology and from population studies conducted in 7 regions of the Czech Republic. It performed 52 648 spectrophotometric analysis of urinary iodine in the general population. METHODS: Urinary iodine was determined by alkali melting of urine samples, followed by spectrophotometric determination of iodine in the form of iodide using the Sandell-Kolthoff reaction in the Institute of Endocrinology or determination was performed by ICP-MS in the laboratory of NIPH. RESULTS: On average, only 21.8 % of pregnant women had urinary iodine values determined by spectrophotometry higher than 150 µg/L. The results of iodine nutrition of pregnant women in the first trimester analyzed using ICP-MS are better, but even so, only 50.5 % of pregnant women have urinary iodine higher than 150 µg/L. CONCLUSION: The results of iodine nutrition of pregnant women are alarming, on average, only 30 % of the total of 750 examined women have urinary iodine values greater than 150 µg/L and therefore meet the requirements of the WHO for pregnant women. Our results, however, show that iodine deficiency is not major public health problem in the general population.Key words: ICP-MS - pregnant women - Sandell-Kolthoff reaction - urinary iodine.

The presence of monoiodinated derivates of daidzein and genistein in human urine and its effect on thyroid gland function.

Dietary supplements used by women during menopause are usually based on plant extracts containing isoflavonoids, daidzein and genistein. Genistein is a known inhibitor of many enzymes, including thyroid peroxidase (TPO). In the thyroid follicle, genistein acts as its alternate substrate for the formation of genistein iodinated derivatives. The aim of this study was to search for daidzein- and genistein-iodinated derivatives in urine of isoflavonoid-supplemented women. Additionally, selected phytoestrogens, steroid and thyroid hormones before and after three months of phytoestrogen supplementation were estimated. Urinary levels of free phytoestrogen increased significantly after therapy. They ranged between 0.3-1600, 0.6-670 and 0-206 nmol/L for daidzein, genistein and S-equol, respectively. Monoiodinated derivatives of genistein were observed (0-504 pmol/L) in 60% of the investigated samples. Steroid and thyroid hormone levels were within the normal range and were not significantly altered. The presence of monoiodinated derivates in human urine confirmed that genistein and daidzein may enter human thyroid follicles and influence TPO. Since the levels of the free thyroid hormones were not affected, we propose that the use of phytoestrogen dietary supplements is not associated with the development of thyroid-gland disorders in subjects with adequate iodine intake.