A Randomized Trial of Selenium Supplementation and Risk of Type-2 Diabetes, as Assessed by Plasma Adiponectin
What this study found
Selenium supplementation did not change plasma adiponectin, suggesting no diabetogenic effect in this population. Compared with placebo, adiponectin decreased by 4% with 100 mg/d, 1% with 200 mg/d, and remained unchanged with 300 mg/d; the overall comparison of the three active groups versus placebo was not significant (P = 0.96). Plasma selenium increased significantly and proportionally to dose in the active groups, but no serious adverse events occurred. Twelve adverse events were reported, mainly stomach or abdominal discomfort, and were similarly associated with selenium and placebo.
- Study & population
- Randomized, placebo-controlled, double-blind trial in elderly volunteers recruited from four general practices in the United Kingdom, with relatively low baseline selenium status.
- Intervention
- Participants received oral high-selenium yeast (SelenoPrecise, Pharma Nord) at 100 mg/d, 200 mg/d, or 300 mg/d for a minimum of six months, compared with identical placebo.
- Key limitation
- Per-arm randomized and analyzed sample sizes were not reported in the excerpt, and adiponectin data were incomplete: 473 participants had at least one plasma sample and 340 had both baseline and six-month measurements.
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Open PDFOriginal abstract
Background Evidence that selenium affects the risk of type-2 diabetes is conflicting, with observational studies and a few randomized trials showing both lower and higher risk linked to the level of selenium intake and status. We investigated the effect of selenium supplementation on the risk of type-2 diabetes in a population of relatively low selenium status as part of the UK PRECISE (PREvention of Cancer by Intervention with SElenium) pilot study. Plasma adiponectin concentration, a recognised independent predictor of type-2 diabetes risk and known to be correlated with circulating selenoprotein P, was the biomarker chosen. Methods In a randomized, double-blind, placebo-controlled trial, five hundred and one elderly volunteers were randomly assigned to a six-month intervention with 100, 200 or 300 µg selenium/d as high-selenium or placebo yeast. Adiponectin concentration was measured by ELISA at baseline and after six months of treatment in 473 participants with one or both plasma samples available. Results Mean (SD) plasma selenium concentration was 88.5 ng/g (19.1) at baseline and increased significantly in the selenium-treatment groups. In baseline cross-sectional analyses, the fully adjusted geometric mean of plasma adiponectin was 14% lower (95% CI, 0–27%) in the highest than in the lowest quartile of plasma selenium (P for linear trend = 0.04). In analyses across randomized groups, however, selenium supplementation had no effect on adiponectin levels after six months of treatment (P = 0.96). Conclusions These findings are reassuring as they did not show a diabetogenic effect of a six-month supplementation with selenium in this sample of elderly individuals of relatively low selenium status. Trial Registration Controlled-Trials.com ISRCTN25193534