Prevalence of iodine deficiency among vegan compared to vegetarian and omnivore children in the Czech Republic: cross-sectional study.

BACKGROUND: The intake and homeostasis of iodine, an essential micronutrient that plays a vital role in thyroid physiology, is of particular concern with the increasing popularity of vegetarian (VG) and vegan (VN) diets. Children on these restrictive diets may be at risk of possible adverse effects on growth and development, but there is currently a lack of recent epidemiological studies on this topic. METHODS: We gathered clinical, anthropometric, and blood/urine data on iodine status and thyroid function from children aged 0-18 years who followed either a VG diet (n = 91), VN diet (n = 75), or omnivore diet (OM, n = 52). Cross-sectional comparison of the groups and linear regression was used. Stratified analyses were performed based on age (according to WHO): 0-5 years and 6-18 years. RESULTS: Our study revealed no significant differences in levels of thyroid-stimulating hormone (TSH), triiodothyronine (fT3), thyroglobulin (TG) or anti-thyroid peroxidase antibody (ATPOc) between the VG, VN, and OM groups. However, thyroxine (fT4) levels were found to be higher in the VN group compared to the OM group (15.00 ± 1.73 vs. 16.17 ± 1.82 pmol/l, p < 0.001). The presence of anti-thyroglobulin antibodies (AhTGc) was notably more common in the VG (18.2%)/VN (35.0%) groups than in the OM group (2.1%) (p < 0.001). Regarding iodine status, the concentration of iodine in spot urine (UIC) was found to be highest in the OM group (197.28 ± 105.35 vs. VG: 177.95 ± 155.88 vs. VN: 162.97 ± 164.51 µg/l, p < 0.001). Notably, the lowest (5.99 µg/l) and highest (991.80 µg/l) levels were measured in the VN group. Of the participants, 31 VN, 31 VG and 10 OM children met the criteria for iodine deficiency (i.e., UIC < 100 µg/l). We found that children with regular iodine supplementation had higher UIC (p < 0.001). Importantly, the median UIC was above 100 µg/l in all three groups, through the recommended intake (RDI) of iodine was rarely met throughout the groups. CONCLUSION: We have observed a trend to lower UIC values in VN as compared to OM. This trend is also reflected in the median UIC values, even though the median UIC values were above the WHO cut-off (e.g., 100 µg/l) for iodine deficiency in all dietary groups. These results suggest that VN and VG children may be more at higher risk of iodine deficiency, this theory is also supported by higher prevalence of AhTGc positivity. Further research is needed to investigate the long-term impact of these dietary patterns on iodine status and thyroid function in children. Given our findings, it may also be necessary to consider new guidelines for supplementing children following VG and VN diets to ensure their iodine needs are met.

Cross-Sectional Study of the Prevalence of Cobalamin Deficiency and Vitamin B12 Supplementation Habits among Vegetarian and Vegan Children in the Czech Republic.

Vegetarian (VG) and vegan (VN) diets in childhood are of growing interest due to their perceived health and environmental benefits. Concerns remain due to the possible disruption of healthy growth and development of children because of the scarcity of evidence-based studies. Among the nutrients of special concern is vitamin B12. Therefore, the Czech Vegan Children Study (CAROTS) decided to examine the relationship between B12 metabolism parameters and B12 intake through diet and supplementation. We analyzed laboratory parameters within n = 79 VG, n = 69 VN, and n = 52 omnivores (OM) children (0−18 years old). There were no significant differences in levels of holotranscobalamin (aB12), folate, homocysteine (hcys), or mean corpuscular volume. However, there was a significant difference in levels of cyanocobalamin (B12) (p = 0.018), even though we identified only n = 1 VG and n = 2 VN children as B12 deficient. On the other hand, we identified n = 35 VG, n = 28 VN, and n = 9 OM children with vitamin B12 hypervitaminosis (p = 0.004). This finding was related to a high prevalence of over-supplementation in the group (mean dose for VG 178.19 ± 238.5 µg per day; VN 278.35 ± 394.63 µg per day). Additionally, we found a significant (p < 0.05) difference between B12, aB12, and hcys levels of supplemented vs. non-supplemented VG/VN children. This can show that the intake of vitamin B12 via diet in the VG group might not be sufficient. Secondly, we analyzed a relation between supplement use in pregnancy and breastfeeding and its impact on vitamin B12 levels of children aged 0−3 years. Out of n = 46 mothers, only n = 3 (e.g., 6.5%) were not supplemented at all. We have not identified any clinical manifestation of B12 deficiency and only n = 1 child with low serum cobalamin, a child who did not receive vitamin B12 supplementation and whose mother took only low doses of vitamin B12 (25/µg/day).To conclude, we did not observe any life-threatening or severe consequences of laboratory-stated vitamin B12 deficiency; thus, our group was well supplemented. On the other hand, we have identified many subjects with vitamin B12 hypervitaminosis of unknown impact on their health. Further research and new guidelines for B12 supplementation among VG and VN children are needed.

Iodine intake monitoring in neonatal population in the Czech Republic: alarming numbers in 2020.

Thanks to comprehensive and long-term preventive programs, the Czech Republic has taken its place among the countries with a resolved iodine deficiency at all population levels since 2004. A sensitive indicator of iodine supply to the population, which can also be used to monitor the efficiency of prophylactic programs, is the TSH assessment in the nationwide neonatal screening of congenital hypothyroidism. Nevertheless, recent results of neonatal TSH show that newborns and pregnant women remain very risky groups and their iodine saturation is borderline. In recent years, the percentage of newborns with TSH 5-15 mIU/l has already risen above the 3% mark, i.e. mild iodine deficiency in major part of the Czech Republic (3.8 % in Bohemia, 2.8% in Moravia in 2019 and 4.7 % in Bohemia, 2.9% in Moravia in 2020). For some smaller areas, the values are even higher, which can be related, for example, to the social patterns of the population. The result may be not only the exclusion of the Czech Republic from the list of countries with resolved iodine deficiency, but especially adverse consequences for the cognitive development of the future generation. Therefore, it is essential to intensify nation-wide intervention among both the professional and general public. In this regard, adherence to the supplementation of pregnant and breastfeeding women is crucial with 150-200 μg of iodide in addition to nutritional iodine intake.

Problematics of iodine saturation among children on the vegan diet.

Plant-based diets, which includes veganism, is now rapidly gaining popularity. In the absence of the knowledge how to provide all the risky nutrients, this style of eating can lead to nutritional deficits that result in disruption of the physiological development of the child. One of the risk elements also includes iodine. The vegan population is at risk not only of developing an iodine deficiency, but also of complications from its excessive consumption, since vegan alternatives, such as these made of seaweed, contain an excess amount of it. Iodine is essential for the proper functioning of the thyroid gland, whose hormones are involved in the development of the nervous system during intrauterine and postnatal development, and in the regulation of metabolism, as well as growth in children. Several physical (thyroid palpation), imaging (ultrasound) and laboratory methods (TSH, fT3/fT4 ratio, TG level, median of ioduria) are used to investigate iodine supply. For vegans it is essential to closely monitor iodine saturation and to edify the need to adequately supplement the diet of vegan diets. A possible vegan iodine source are precisely measured doses of mineral water (Vincentka) or iodine tablets. On the contrary, uncontrolled consumption of seaweed must be strictly discouraged. In terms of iodine supply, vegans are a risk group, and pregnant and breastfeeding women and children on vegan diets deserve increased attention.

Novel presentation of the c.1856A > G (p.Asp619Gly) TSHR gene-activating variant: relapsing hyperthyroidism in three subsequent generations manifesting in early childhood and an in vitro functional study.

BACKGROUND: Familial non-autoimmune hyperthyroidism is a rare disease caused by germline activating variants in the thyroid-stimulating hormone receptor (TSHR) gene. The c.1856A > G (p.Asp619Gly) pathogenic variant has been described in cases of toxic adenoma but never before, to our knowledge, in a case of familial non-autoimmune hyperthyroidism. PATIENT FINDINGS: A 3-year-old boy was admitted for acute gastroenteritis presenting with goiter and tall stature. Laboratory findings revealed peripheral hyperthyroidism and negativity for thyroid autoantibodies. Antithyroid drug treatment was effective, but relapses occurred shortly after attempts to decrease the drug dose. As the boy's father and paternal grandmother also experienced relapsing hyperthyroidism manifesting in early childhood, genetic testing of TSHR was indicated. The c.1856A > G (p.Asp619Gly) pathogenic variant was found in all three affected family members. Functional in vitro characterization of the variant verified that it enhances constitutional activation of the receptor, leading to increased production of cyclic adenosine monophosphate. Total thyroidectomy was indicated in the boy due to an unsatisfactory prognosis. Due to persistent positive thyroglobulin serum concentration, a diagnostic radioiodine scan was performed approximately 2 years later. Residual thyroid tissue was revealed; therefore, radioiodine ablative therapy was performed. Despite adequate thyroxine substitution over a long period of follow-up, TSH remained suppressed. CONCLUSIONS: Unlike Graves' disease, familial non-autoimmune hyperthyroidism cases present with antithyroid drug-dependence. Not ultrasound but positive thyroglobulin serum concentration indicated residual thyroid tissue. Early detection of residual thyroid tissue and radioiodine ablation prevented the subject from experiencing relapsing hyperthyroidism and undergoing unnecessary repeated surgery. Life-long hormone substitution should be adjusted to free thyroxine rather than TSH serum concentrations.

Problematics of iodine saturation among children on the vegan diet.

Plant-based diets, which includes veganism, is now rapidly gaining popularity. In the absence of the knowledge how to provide all the risky nutrients, this style of eating can lead to nutritional deficits that result in disruption of the physiological development of the child. One of the risk elements also includes iodine. The vegan population is at risk not only of developing an iodine deficiency, but also of complications from its excessive consumption, since vegan alternatives, such as these made of seaweed, contain an excess amount of it. Iodine is essential for the proper functioning of the thyroid gland, whose hormones are involved in the development of the nervous system during intrauterine and postnatal development, and in the regulation of metabolism, as well as growth in children. Several physical (thyroid palpation), imaging (ultrasound) and laboratory methods (TSH, fT3/fT4 ratio, TG level, median of ioduria) are used to investigate iodine supply. For vegans it is essential to closely monitor iodine saturation and to edify the need to adequately supplement the diet of vegan diets. A possible vegan iodine source are precisely measured doses of mineral water (Vincentka) or iodine tablets. On the contrary, uncontrolled consumption of seaweed must be strictly discouraged. In terms of iodine supply, vegans are a risk group, and pregnant and breastfeeding women and children on vegan diets deserve increased attention.