Brief reportDietary zinc intake and the risk of depression in middle-aged men: A 20-year prospective follow-up study
Introduction
Zinc is an immunomodulatory trace element that has been suggested to be potentially beneficial in the augmentation of antidepressant therapy (Lai et al., 2012). In addition to immunomodulatory effects, zinc also modulates the functions of the hypothalamus–pituitary–adrenal (HPA) axis, as well as serotonergic and NMDA receptor activity in the central nervous system (Huang, 1997, Szewczyk et al., 2009, Szewczyk et al., 2011, Takeda and Tamano, 2009). The hippocampus and amygdala, which are mood-regulation-related brain areas known to be altered in depression, also have large numbers of zinc-containing neurons (Brown and Dyck, 2004).
Cross-sectional general population studies have suggested that a low dietary zinc intake is associated with depression in women (Jacka et al., 2012, Maserejian et al., 2012), but not in men (Maserejian et al., 2012). An association between depression and zinc intake has also been observed in mixed-gender samples of postgraduate students (Yary and Aazami, 2012) and elderly individuals (Marcellini et al., 2006).
To date, only two large population-based studies have examined the cross-sectional association between dietary zinc intake and depression (Jacka et al., 2012, Maserejian et al., 2012). Furthermore, there have been no prospective studies focusing on the association between the incidence of depression and zinc intake. The objective of this study was to examine the impact of dietary zinc intake on the risk of incident depression in 2317 Finnish middle-aged men.
Section snippets
Study setting and participants
The Kuopio Ischemic Heart Disease Risk Factor Study is a population-based study focusing on risk factors for ischemic heart disease and other outcomes among middle-aged men in the Kuopio region of eastern Finland (Salonen, 1988). A total of 2682 participants aged 42–60 years were recruited for the baseline examination, which occurred between March 1984 and December 1989. Data were incomplete for 82 participants, and complete data were therefore available for 2600 men. All participants provided
Results
A total of 60 (2.7%) men were discharged with a depression diagnosis during the follow-up. Altogether, 2189 (94.5%) of the participants reached the Finnish zinc RDI for men (≥9 mg/d; National Nutrition Council, 2005).
Discussion
To the best of our knowledge, this was the first prospective study examining the association between dietary zinc and the risk of depression. Dietary zinc intake was not associated with an increased risk of depression diagnosed upon hospitalization discharge in a 20-year follow-up in men, regardless of adjustments for age, dietary supplement use and several lifestyle factors.
Our findings indicated a modest but significant inverse correlation between dietary zinc intake and depression in men in
Conflict of interest
None declared.
Role of funding source
The authors conducted this study as part of their work, without external funding. Thus, the funding had no role in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication.
Acknowledgments
The authors thank the personnel of the former Research Institute of Public Health for their valuable contribution to this study.
References (24)
- et al.
Nutrient intakes and the common mental disorders in women
Journal of Affective Disorders
(2012) - et al.
The efficacy of zinc supplementation in depression: systematic review of randomised controlled trials
Journal of Affective Disorders
(2012) - et al.
Lower serum zinc in major depression in relation to changes in serum acute phase proteins
Journal of Affective Disorders
(1999) - et al.
Low dietary or supplemental zinc is associated with depression symptoms among women, but not men, in a population-based epidemiological survey
Journal of Affective Disorders
(2012) - et al.
Higher zinc intake buffers the impact of stress on depressive symptoms in pregnancy
Nutrition Research
(2010) - et al.
The involvement of serotonergic system in the antidepressant effect of zinc in the forced swim test
Progress in Neuro-Psychopharmacology & Biological Psychiatry
(2009) - et al.
The role of zinc in neurodegenerative inflammatory pathways in depression
Progress in Neuro-Psychopharmacology & Biological Psychiatry
(2011) - et al.
Insight into zinc signaling from dietary zinc deficiency
Brain Research Reviews
(2009) - et al.
Compendium of physical activities: classification of energy costs of human physical activities
Medicine & Science in Sports & Exercise
(1993) - et al.
Distribution of zincergic neurons in the mouse forebrain
Journal of Comparative Neurology
(2004)