Teresa Urbano, Tommaso Filippini, Marcella Malavolti, Bernhard Michalke, Marco Vinceti
8th FESTEM Symposium, Madrid, September 28-October 1, 2022
Abstract
Introduction: Selenium (Se) is an essential trace element with both toxicological and nutritional features, thus both its deficiency and excess may be detrimental to health. Selenium properties also strongly differ depending on the chemical compound in which it exists in nature. In this study we used serum levels as biomarker of selenium exposure and performed speciation analysis in order to assess the association of selected selenium species (selenite, selenate, selenocysteine-bound-Se (Se-Cys), selenomethionine-bound-Se (Se-Met), selenoprotein P-bound-Se (SelenoP), glutathione peroxidase-bound-Se (Se-GPX), thioredoxin reductase-bound-Se (Se-TrxR), and human serum albumin-bound selenium (Se-HSA)) with four dietary patterns, i.e., the DASH diet (Dietary Approach to Stopping Hypertension), the Italian (IMI) and Greek (GMI) Mediterranean diets, and the MIND diet (Mediterranean-DASH Intervention for Neurodegenerative Delay).
Material and methods: 148 eligible subjects aged 35-60 years were recruited in the Transfusion Medicine Center ‘Casa del Dono’ of AUSL-IRCCS of Reggio Emilia from April 2017 to April 2019. Inclusion criteria were to be not affected by any chronic disease and to be non-smokers. A semi-quantitative food frequency questionnaire (EPIC-FFQ) was administered to assess the adherence to the four dietary patterns along with a questionnaire for demographic characteristics. Fasting serum samples were collected at recruitment and used for the quantification of total serum selenium and its species. High-pressure liquid chromatography (HPLC) along with inductively coupled plasma-dynamic reaction cell-mass spectrometry (ICP-DRC-MS) method was used. The associations between adherence to the dietary patterns with total serum and selenium species were assessed through spline regression analyses adjusted for age, sex, and body mass index.
Results: After the withdrawn of four subjects and exclusion of seven because of high urinary cotinine content, 137 participants were eventually enrolled in the study. Our population was composed of 62 men and 75 women with a mean age of 47.4 years. Median total serum selenium levels were 116.50 mcg/L, interquartile range (IQR) 106-128 mcg/L. Adherence to the MIND diet was linearly negative associated with total serum selenium levels, while the association was inverted U-shaped for IMI and GMI and almost null for the DASH diet, which was also negatively associated with selenoP, inverted U-shaped related to selenate, while a clear positive association only emerged with Se-Met above 25-score. The same pattern of associations emerged between the IMI and GMI, which a slight positive association with Se-Met and selenite, inverted U-shaped with selenoP, Se-Cys and selenate, and U-shaped with Se-GPX. The MIND diet was negatively associated with selenoP and with selenite and Se-HSA above 8-score of adherence. U-shaped associations emerged with Se-GPX and Se-Cys.
Conclusion: Our results suggest that a greater adherence to the dietary patterns based on the Mediterranean diet are associated with lower serum levels of the trace element selenium and of selected selenium species, particularly the organic species selenoP, and the inorganic selenate.