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Background: Vegetarian (VG) and vegan (VN) diets are becoming increasingly popular among children. These restrictive types of diet remain a concern as they may impair growth and development, although up-to-date epidemiological studies are lacking. Iodine, an essential micronutrient, is of specific concern due to its important role in thyroid gland physiology. Methods: We collected clinical, anthropometric, and blood/urine parameters of iodine status as well as thyroid function among children following VG (n = 91), VN (n = 75), and omnivores (OM, n = 52), aged 5.4 (± 4.3) years. Results: We found no significant differences in levels of thyroid-stimulating hormone (TSH), triiodothyronine (fT3), or thyroglobulin (TG) between the groups. Thyroxine (fT4) levels were higher in OM compared to VN (15.00 ± 1.73 vs. 16.17 ± 1.82 pmol/L, p < 0.001). There were strong differences in anti-thyroglobulin antibodies (AhTGc) between groups (OM: 2.54 ± 8.31 vs. VG: 16.24 ± 44.46 vs. VN: 13.93 ± 9.16 UI/L, p < 0.001). Iodine concentration in spot urine (UIC) was highest in OM (195.31 ± 105.28 vs VG: 177.27 ± 155.13 vs. VN: 162.94 ± 163.39 µg/L, p < 0.001). The lowest (5.99 µg/L) but also the highest (991.80 µg/L) levels were measured in VN. 31 VN and 31 VG children met the criteria for iodine deficiency (i.e., UIC < 100 µg/L). Children with regular iodine supplementation had higher UIC (p < 0.001). Conclusion: We observed a higher prevalence of iodine deficiency in VN and VG group than in OM, with possible impact on thyroidal health (i.e., positivity of antibodies). Further research and new guidelines for iodine supplementation among VG and VN children are therefore warranted.

Background Hyperglycaemia was shown to be among the features of severe acute COVID-19 infection both in the acute and convalescence period. Mechanisms contributing to its development and/or maintenance in a post-COVID phase are still unclear. Materials and Methods Survivors of severe COVID-19 but without a known history of diabetes were examined at baseline (T0) and after 3 (T3) and 6 (T6) months: indirect calorimetry and OGTT. Insulin response and sensitivity (IS) were expressed as insulinogenic (IGI), disposition (DI), and Matsuda insulin sensitivity index (ISI), respectively. Resting energy expenditure (REE) was calculated using the Weir and Harris-Benedict equation and substrate preference using the respiratory quotient (RQ) and nitrogen losses. Results Thirty-two patients (12 women) were available for the analyses at T0 and 26 at T6. Baseline examination was within 21±6.5 days after COVID-19 diagnosis. Patients were hypermetabolic at baseline (30.7 ± 4.3 kcal/kg lean mass/day, ~120% predicted values) but REE declined over the 6 months (ΔT6-T0 mean difference (95% CI): -5.4 (-6.8, -4.1) kcal/kg lean mass/day, pH=3.07 ± 1.18, ISIN=3.23 ± 1.72, p=0.66), whereas insulin response was lower in the H group only (DIH=3.19 ± 2.16 vs DIN=8.78 ± 6.37, p=0.005). Over the 6 months, IS improved in the H group (ΔT6-T0 mean difference for ISI (95% CI): 1.84 (0.45, 3.24), p=0.01)), whereas IGI and DI did not improve in either group. Conclusions Severe COVID-19 infection was associated with hypermetabolism that did not persist over the follow-up. Patients were insulin resistant in the acute phase, but only those with insufficient insulin response developed hyperglycaemia. Insufficient beta cell response was a possible mechanism leading to hyperglycaemia.

It has been shown that many molecules released by adipose tissue (AT) into interstitial fluid can reach the bloodstream preferentially via lymphatic system. Worsened lymphatic drainage may alter interstitial fluid (ISF) composition and thus affect microenvironment of adipocytes. Nevertheless, the effect of lymphatic drainage on AT functions remains unknown. Therefore, we analyzed the lipolytic activity of femoral AT in two groups of premenopausal women similar in adiposity but differing in the efficiency of lymphatic drainage of lower body as assessed by lymphoscintigraphy. Levels of lipolytic markers were assessed in plasma and ISF collected by skin blister technique in femoral area. In addition, microdialysis was used to monitor lipolysis of AT in vivo. Our results indicate that worsened lymphatic drainage is associated with lower in vivo lipolytic index and reduced lipolytic responsiveness of femoral AT to adrenergic stimuli. Thus, efficiency of lymphatic drainage appears to play a role in the regulation of AT metabolism. Accordingly, worsened lymphatic drainage could contribute to the resistance of lower body AT to intentional weigh loss.