From suboptimal to supersaturation: Selenium status after bariatric surgery is modulated by supplementation.

Metabolic and bariatric surgery (MBS) is a proven treatment for obesity but increases risk of nutrient deficiencies. Guidelines recommend vitamin and mineral supplementation after MBS but omits selenium. Adequate selenium status is associated with reduced incidence of chronic diseases, including sarcopenia, yet excess selenium intake is not innocuous. Whilst selenoprotein P is the preferred marker of status, no studies have investigated selenoprotein P after MBS. This cross-sectional study compared Selenoprotein P, plasma selenium and dietary selenium in adults older than 65 years with (BAR) or without previous MBS (CON). Dietary selenium intake was calculated using locally available composition data; Selenoprotein P was categorised as suboptimal, saturated, and supersaturated; and plasma selenium as suboptimal, adequate, and replete. Subgroups were created by selenium supplementation practises (supp vs. none) and linear regression was used to investigate predictors of selenoprotein P. Fifty participants were included per group (BAR 40% male, CON 36%) and BAR participants were two years younger and fewer had diabetes (28% vs 52%). Both selenoprotein P and plasma selenium were higher in BAR-supp compared to BAR-none or CON-none. BAR-supp had a lower prevalence of suboptimal selenoprotein P levels compared to BAR-none (7% vs. 43%) but more participants had supersaturated levels (28% vs 0%). The predictors of selenoprotein P were supplemented selenium, dietary selenium, and total weight loss. Whilst the clinical relevance of Selenoprotein P supersaturated remains uncertain, further studies are needed to investigate the ideal supplement dosage and the impact of surgery type on selenium requirements.