The impact of selenium supplementation on mood

The possibility that a subclinical deficiency of the trace element selenium might exist in a sample of the British population was examined by giving a selenium supplement for 5 weeks. Using a double-blind cross-over design, 50 subjects received either a placebo or 100 mcg selenium on a daily basis. On three occasions they filled in the Profile of Moods States. A food frequency questionnaire was used to estimate the intake of selenium in the diet. Intake was associated with a general elevation of mood and in particular, a decrease in anxiety. The change in mood when taking the active tablet was correlated with the level of selenium in the diet, which was estimated from a food frequency questionnaire. The lower the level of selenium in the diet the more reports of anxiety, depression, and tiredness, decreased following 5 weeks of selenium therapy. The results are discussed in terms of the low level of selenium in the food chain in some parts of the world.