The Role of Micronutrients in Depressive Symptoms and Mood: An Investigation of Iron and Selenium

Abstract

Previous studies have reported that low micronutrient levels are associated with increased depressive symptoms and poorer mood. Few studies have tested associations between micronutrient levels and mood specifically in young adult populations. Furthermore, two micronutrients, iron and selenium, have received relatively less attention. This thesis examined associations between iron levels and selenium concentrations and depressive symptoms in a non-clinical sample of young adults. Participants were university students aged 17 to 25 years who were recruited as part of the Daily Life Study. On the first day of the study, participants completed a series of questionnaires, including the Centre for Epidemiologic Studies Depression scale. After this initial series of questionnaires, participants completed an Internet daily diary for 13 days, which included daily mood ratings. On the 14th day of the study participants attended a clinic to give a non-fasting venous blood sample. In Study 1, associations between iron levels and depressive symptoms, daily mood, and tiredness were examined separately in women and men. There were no associations between body iron levels and mood for young adult women, although young adult men with higher body iron reported higher levels of depressive symptomatology. In Study 2, associations between selenium concentrations and both depressive symptoms and daily mood were examined for women and men together. Both low and high selenium concentrations were found to be associated with higher levels of depressive symptoms and daily negative mood, and less positive mood. Taken together, the results of these two studies suggest that iron levels and selenium concentrations may be associated with depressive symptoms in young adults. These findings add to the growing evidence base that micronutrient levels may play a significant role in mental health.