Selenium deficiency is linearly associated with hypoglycemia in healthy adults.

OBJECTIVE: The trace element selenium (Se) is needed for regular biosynthesis of selenoproteins, which contribute to antioxidative defense systems and affect redox-regulated signaling. Elevated Se intake and selenoprotein expression levels have been associated with impaired hydrogen peroxide-dependent signaling by insulin, leading to hyperglycemia and insulin resistance. The relation of low Se intake with glucose status and carbohydrate metabolism is poorly known. RESEARCH DESIGN AND METHODS: A cross sectional analysis among healthy subjects residing in two Chinese counties with different habitual Se intakes was conducted. Fasted glucose levels were related to Se concentrations of 5686 adults by linear regression analysis with Se, body mass index, age, thyroid status, insulin and sex as independent variables. RESULTS: Serum Se correlated strongly and positively with glucose in the Se-deficient population. There was no strong relationship of Se and glucose in the non-deficient population. Overt hypoglycemia (serum glucose < 2.8 mM) was observed in 19.2% of this random sample of subjects in the Se-deficient and in 1.4% of the moderately supplied population, respectively. CONCLUSIONS: An adequate Se supply constitutes an important factor for glucose homeostasis in human subjects. The interaction between Se status and glucose control is not limited to hyperglycemia, but apparently extends to hypoglycemia risk in Se deficiency. This newly identified relationship may be of relevance for the course of severe disease including major trauma, sepsis and COVID-19, where Se deficiency has been associated with mortality risk.

Low Population Selenium Status Is Associated With Increased Prevalence of Thyroid Disease.

CONTEXT: Epidemiological studies have supported the premise that an adequate selenium intake is essential for thyroid gland function. OBJECTIVE: The objective was to investigate whether the prevalence of thyroid disease differed in two areas that were similar, except for very different soil/crop selenium concentrations. DESIGN: Cross-sectional observational study. SETTING: The setting was two counties of Shaanxi Province, China, here defined as adequate- and low-selenium. PARTICIPANTS: A total of 6152 participants were selected by stratified cluster-sampling. MAIN OUTCOME MEASURES: Participants completed demographic and dietary questionnaires and underwent physical and thyroid ultrasound examinations. Serum samples were analyzed for thyroid function parameters and selenium concentration. Serum selenium was compared between different demographic, dietary, and lifestyle categories in the two counties. The relationship between selenium status, dietary factors, and pathological thyroid conditions was explored by logistic regression. RESULTS: Complete data sets were available from 3038 adequate-selenium participants and 3114 low-selenium participants in whom median (interquartile range) selenium concentrations differed almost 2-fold (103.6 [79.7, 135.9] vs 57.4 [39.4, 82.1] µg/L; P = .001). The prevalence of pathological thyroid conditions (hypothyroidism, subclinical hypothyroidism, autoimmune thyroiditis, and enlarged thyroid) was significantly lower in the adequate-selenium county than in the low-selenium county (18.0 vs 30.5%; P < .001). Higher serum selenium was associated with lower odds ratio (95% confidence interval) of autoimmune thyroiditis (0.47; 0.35, 0.65), subclinical hypothyroidism (0.68; 0.58, 0.93), hypothyroidism (0.75; 0.63, 0.90), and enlarged thyroid (0.75; 0.59, 0.97). CONCLUSIONS: Low selenium status is associated with increased risk of thyroid disease. Increased selenium intake may reduce the risk in areas of low selenium intake that exist not only in China but also in many other parts of the world.