MedWire News: High levels of serum selenium are associated with elevated total and low-density lipoprotein (LDL) cholesterol, report US researchers.
The results add weight to those of a previous UK study, reported by MedWire News, that reported an association between high plasma selenium and an adverse lipid profile.
Eliseo Guallar (Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland) and colleagues carried out a cross-sectional analysis of 1159 individuals aged 56.8 years on average who participated in the National Health and Nutrition Examination Survey (NHANES) 2003–2004.
Levels of serum selenium were measured by the researchers using inductively coupled plasma-dynamic reaction cell-mass spectrometry.
Mean levels for the overall cohort were 136.7 µg/l. When divided into quartiles, serum selenium ranged from below 124 µg/l in the lowest quartile to 147 µg/l and above in the highest.
Writing in the journal Atherosclerosis, the team report that total and LDL cholesterol concentration increased progressively with increasing selenium levels.
Total cholesterol, LDL cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides were 18.9, 12.7, 3.9, and 11.5 mg/dl (0.49, 0.34, 0.10, and 0.30 mmol/l) higher, respectively, in the top than the bottom selenium quartile.
Of note, the association with HDL cholesterol reached a plateau above 120 µg/l selenium and the triglyceride association was U-shaped.
“The use of vitamin/mineral supplements has likely contributed to the increase in selenium levels over the last decade, as reflected by the high percentage of dietary supplement users in the top quartiles of serum selenium in the present study,” say Guallar et al.
“Increasing selenium intake in individuals with a replete selenoprotein status, such as the average NHANES participant, has little potential for additional health benefits but can result in toxic effects.”
They conclude: “The relationship between selenium status and atherosclerosis is more complex than its role as antioxidant and should be clarified to enlighten preventive and therapeutic uses of selenium and to help determine the optimal level of selenium intake in the general population that maximizes the antioxidant benefits but avoids potential subclinical toxic effects of selenium.”
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
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Concern about possible adverse lipid effects of high selenium levels