Isabelle Herter-Aeberli1, Mohamed Cherkaoui2, Nawal El Ansari3, Riccarda Rohner4, Sara Stinca4, Laila Chabaa5, Arnold von Eckardstein6, Abdelmounaim Aboussad3, Michael B Zimmermann7. 1. Human Nutrition Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland; isabelle.herter@hest.ethz.ch. 2. Laboratory of Human Ecology, Faculty of Sciences Semlalia, and. 3. Medical and Pharmaceutical Faculty, University Cady Ayyad, Marrakesh, Morocco; Mohammed VI University Hospital, Marrakesh, Morocco; 4. Human Nutrition Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland; 5. Mohammed VI University Hospital, Marrakesh, Morocco; 6. Institute for Clinical Chemistry, University Hospital Zurich, Zurich, Switzerland; and. 7. Human Nutrition Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland; Iodine Global Network, Zurich, Switzerland.
Abstract
BACKGROUND: In iodine deficiency, thyrotropin (TSH) may increase to stimulate thyroidal iodine uptake. In iodine-sufficient populations, higher TSH predicts higher total cholesterol. Whether higher TSH caused by iodine deficiency affects serum lipids is uncertain. OBJECTIVE: Our aim was to determine if iodine repletion decreases serum TSH and improves the lipid profile. METHODS: In this randomized controlled intervention, iodine-deficient, overweightor obese Moroccan women (n = 163) received 200 μg oral iodine or a placebo daily for 6 mo. Main outcomes were serum TSH and plasma total and LDL cholesterol. Secondary outcomes included thyroid hormones and measures of lipid and glucose metabolism and urinary iodine concentration (UIC). Data were compared by using mixed-model analysis. RESULTS: In the intervention group, median UIC increased from 38 (95% CI: 34, 45) μg/L to 77 (95% CI: 59, 89) μg/L (P < 0.001). After 6 mo of intervention, TSH was 33% lower in the treatment group than in the placebo group (P = 0.024). The triiodothyronine (T3) to thyroxine (T4) ratio and thyroglobulin decreased with treatment [-15% (P = 0.002) and -32% (P < 0.001), respectively], whereas T4 concentrations were higher in the treatment group (P < 0.001). Total cholesterol in subjects with elevated baseline cholesterol (>5 mmol/L) was reduced by 11% after the intervention (P = 0.034). At 6 mo, only 21.5% of treated women remained hypercholesterolemic (total cholesterol >5 mmol/L) vs. 34.8% of controls (baseline: 44.2% in the intervention and 36.8% in the control group; P = 0.015). The reduction in the prevalence of elevated LDL cholesterol (>3 mmol/L) in the intervention group (50.6% to 35.4% compared with 47.4% to 44.9% in the control group) was not significant (P-interaction = 0.23). CONCLUSIONS: Our findings suggest that moderate to severe iodine deficiency in overweight women elevates serum TSH and produces a more atherogenic lipid profile and that iodine supplementation in this group reduces the prevalence of hypercholesterolemia. Thus, iodine prophylaxis may reduce cardiovascular disease risk in overweight adults. This trial was registered at clinicaltrials.gov as NCT01985204.
RCT Entities:
BACKGROUND: In iodine deficiency, thyrotropin (TSH) may increase to stimulate thyroidal iodine uptake. In iodine-sufficient populations, higher TSH predicts higher total cholesterol. Whether higher TSH caused by iodine deficiency affects serum lipids is uncertain. OBJECTIVE: Our aim was to determine if iodine repletion decreases serum TSH and improves the lipid profile. METHODS: In this randomized controlled intervention, iodine-deficient, overweight or obese Moroccan women (n = 163) received 200 μg oral iodine or a placebo daily for 6 mo. Main outcomes were serum TSH and plasma total and LDL cholesterol. Secondary outcomes included thyroid hormones and measures of lipid and glucose metabolism and urinary iodine concentration (UIC). Data were compared by using mixed-model analysis. RESULTS: In the intervention group, median UIC increased from 38 (95% CI: 34, 45) μg/L to 77 (95% CI: 59, 89) μg/L (P < 0.001). After 6 mo of intervention, TSH was 33% lower in the treatment group than in the placebo group (P = 0.024). The triiodothyronine (T3) to thyroxine (T4) ratio and thyroglobulin decreased with treatment [-15% (P = 0.002) and -32% (P < 0.001), respectively], whereas T4 concentrations were higher in the treatment group (P < 0.001). Total cholesterol in subjects with elevated baseline cholesterol (>5 mmol/L) was reduced by 11% after the intervention (P = 0.034). At 6 mo, only 21.5% of treated women remained hypercholesterolemic (total cholesterol >5 mmol/L) vs. 34.8% of controls (baseline: 44.2% in the intervention and 36.8% in the control group; P = 0.015). The reduction in the prevalence of elevated LDL cholesterol (>3 mmol/L) in the intervention group (50.6% to 35.4% compared with 47.4% to 44.9% in the control group) was not significant (P-interaction = 0.23). CONCLUSIONS: Our findings suggest that moderate to severe iodine deficiency in overweight women elevates serum TSH and produces a more atherogenic lipid profile and that iodine supplementation in this group reduces the prevalence of hypercholesterolemia. Thus, iodine prophylaxis may reduce cardiovascular disease risk in overweight adults. This trial was registered at clinicaltrials.gov as NCT01985204.
Authors: Stellena Mathiaparanam; Adriana Nori de Macedo; Andrew Mente; Paul Poirier; Scott A Lear; Andreas Wielgosz; Koon K Teo; Salim Yusuf; Philip Britz-Mckibbin Journal: Nutrients Date: 2022-06-21 Impact factor: 6.706
Authors: Oliver C Witard; Sarah C Bath; Mariana Dineva; Laury Sellem; Ana-Isabel Mulet-Cabero; Laura H van Dongen; Ju-Sheng Zheng; Carina Valenzuela; Benoit Smeuninx Journal: Front Nutr Date: 2022-02-10