Background and aim: The metalloid selenium shows an intriguing role with human health, with both nutritional and toxicological effects. In particular, recent studies suggest that high selenium exposure could be associated with impairment of metabolism of lipids, glucose and thyroid function. This study aims at assessing dietary levels of exposure to selenium and assess the correlation between selenium levels and biochemical and metabolic parameters in an Italian community.
Methods: In a sample adult population of ever smokers from Reggio Emilia Province we estimated dietary selenium intake through a food frequency questionnaire, validated for the Northern Italy population. From each participant we collected a fasten blood sample for determination of biochemical parameters and hormone levels, including alanine transaminase, blood glucose, total cholesterol, high-density lipoproteins (HDL), and thyroid-stimulating hormone (TSH). All subjects who participated to this study signed a written informed consent.
Results: In participants recruited from March 2017 to May 2018 the mean (standard deviation) dietary selenium intake was 101.0 (47.3) μg/day. We found negative correlation between selenium intake and HDL levels, while a positive one with TSH levels. Moreover, in sex-stratified analysis, we found a positive association between selenium intake with blood glucose
levels in females.
Discussion: The dietary selenium intake in our Italian population is far above the recommended intake of 70 μg/day by the European Food Safety Authority. Our correlation analyses suggest that even at levels below the upper toxicity limits and generally considered safe, adverse effects on endocrine and metabolic systems could not be excluded, with possible sex-related differences in toxicity susceptibility.
Acknowledgements: We acknowledge the collaboration of the personnel of Transfusion Medicine Unit of AUSL-IRCCS of Reggio Emilia, staff and volunteers of AVIS – Section of Reggio Emilia, and all blood donors who participated to this study.