Higher zinc intake buffers the impact of stress on depressive symptoms in pregnancy

Race as a determinant of prenatal depressive symptoms: analysis of data from the 'All Our Families' study

OBJECTIVES

Prenatal depression is a serious maternal-child health concern. Risk factors and health consequences appear more prevalent in Indigenous communities and ethnic minority groups; however, research on these populations is limited. We examined the following questions: (A) How do pregnant Indigenous women, ethnic minority women, and White women compare on levels of depressive symptoms and possible clinical depression, and on major risk and protective factors? (B) Is non-dominant (non-White) race associated with higher depressive symptoms and possible clinical depression? (C) What factors mediate and moderate the relationship between race and depression?

DESIGN

Data were from the All Our Families study (n = 3354 pregnant women from Alberta, Canada). Depressive symptoms were measured with the Edinburgh Postnatal Depression Scale (EPDS). Descriptive statistics and multivariable regression methods were used to assess the hypotheses that Indigenous and ethnic minority women would have significantly higher mean EPDS score estimates and higher proportions scoring above cut-offs for possible clinical depression, relative to White women. The association between race and depressive symptoms was hypothesised to be partially mediated by risk factors of socioeconomics, health background, discrimination, domestic violence, and psychosocial stress. Potential confounders were age, marital status, and parity. Diet and social support were hypothesised as protective buffers between stress and depressive symptoms.

RESULTS

A higher proportion of White women were married, had family income over $80,000, were employed, and had adequate social support, relative to other women. They had significantly lower mean depressive symptom score, and a smaller proportion scored above cut-offs for possible clinical depression. The positive association between race and depressive symptoms appeared to be partially mediated by socioeconomic factors and psychosocial stress. Social support appeared to moderate the association between stress and depressive symptoms.

CONCLUSIONS

Strategies to address socioeconomic status, stress, and social support among racialized minority women may reduce the risk for prenatal depression.

The role of stress in perinatal depression and anxiety - A systematic review

Perinatal depression (PND) and anxiety affect around 20% of women, but available pharmacotherapy is not sufficiently effective in 20-60% of them, indicating a need for better understanding of these diseases. Since stress is a significant risk factor for PND, the aim was to examine the role of biological, environmental and psychological stress in PND and anxiety through a systematic literature search. Overall 210 studies were included, among which numerous rodent studies showed that perinatal stress induced depressive-like and anxious behavior, which was associated with HPA-axis alterations and morphological brain changes. Human studies indicated that the relationship between cortisol and perinatal depression/anxiety was not as clear and with many contradictions, although social and psychological stress were clearly positively associated with PND. Finally, oxytocin, synthetic neuroactive steroid and n-3 PUFA diet have been identified as potentially beneficial in the therapy of PND and anxiety, worth to be investigated in the future.

Mitochondrial might: powering the peripartum for risk and resilience

The peripartum period, characterized by dynamic hormonal shifts and physiological adaptations, has been recognized as a potentially vulnerable period for the development of mood disorders such as postpartum depression (PPD). Stress is a well-established risk factor for developing PPD and is known to modulate mitochondrial function. While primarily known for their role in energy production, mitochondria also influence processes such as stress regulation, steroid hormone synthesis, glucocorticoid response, GABA metabolism, and immune modulation - all of which are crucial for healthy pregnancy and relevant to PPD pathology. While mitochondrial function has been implicated in other psychiatric illnesses, its role in peripartum stress and mental health remains largely unexplored, especially in relation to the brain. In this review, we first provide an overview of mitochondrial involvement in processes implicated in peripartum mood disorders, underscoring their potential role in mediating pathology. We then discuss clinical and preclinical studies of mitochondria in the context of peripartum stress and mental health, emphasizing the need for better understanding of this relationship. Finally, we propose mitochondria as biological mediators of resilience to peripartum mood disorders.

Biomarkers of Postpartum Depression: A Narrative Review

Postpartum depression (PPD) is a disorder that impairs the formation of the relationship between mother and child, and reduces the quality of life for affected women to a functionally significant degree. Studying markers associated with PPD can help in early detection, prevention, or monitoring treatment. The purpose of this paper is to review biomarkers linked to PPD and to present selected theories on the pathogenesis of the disease based on data from biomarker studies. The complex etiology of the disorder reduces the specificity and sensitivity of markers, but they remain a valuable source of information to help clinicians. The biggest challenge of the future will be to translate high-tech methods for detecting markers associated with postpartum depression into more readily available and less costly ones. Population-based studies are needed to test the utility of potential PPD markers.

Immune System and Psychological State of Pregnant Women during COVID-19 Pandemic: Are Micronutrients Able to Support Pregnancy?

The immune system is highly dynamic and susceptible to many alterations throughout pregnancy. Since December 2019, a pandemic caused by coronavirus disease 19 (COVID-19) has swept the globe. To contain the spread of COVID-19, immediate measures such as quarantine and isolation were implemented. These containment measures have contributed to exacerbate situations of anxiety and stress, especially in pregnant women, who are already particularly anxious about their condition. Alterations in the psychological state of pregnant women are related to alterations in the immune system, which is more vulnerable under stress. COVID-19 could therefore find fertile soil in these individuals and risk more severe forms. Normally a controlled dietary regimen is followed during pregnancy, but the use of particular vitamins and micronutrients can help counteract depressive-anxiety states and stress, can improve the immune system, and provide an additional weapon in the defense against COVID-19 to bring the pregnancy to fruition. This review aims to gather data on the impact of COVID-19 on the immune system and psychological condition of pregnant women and to assess whether some micronutrients can improve their psychophysical symptoms.

The Possible Effects of Zinc Supplementation on Postpartum Depression and Anemia

Background and Objectives: The effects of postpartum zinc supplementation are still unclear. Our purpose in this study is to investigate the association between Zn supplementation and postpartum depression, defined by an Edinburgh Postnatal Depression Scale (EPDS) score ≥ 9, and the effect on the hematological status of postpartum women. Materials and Methods: We first investigated whether zinc supplementation affected the perioperative levels of zinc, hemoglobin, and hematocrit in 197 cases who underwent cesarean section and had postpartum anemia. Next, logistic regression analyses were performed on 148 eligible cases to determine the association between zinc supplementation and postpartum depression. Results: Postpartum zinc supplementation significantly improved the status of maternal blood zinc levels and reduced the risk of developing postpartum depression (adjusted odds ratio: 0.249; 95% confidence interval: 0.062–0.988; p = 0.048). Iron supplementation is a standard and effective strategy for treating anemia; however, the combination of oral iron plus zinc supplementation resulted in slightly significant negative effects on postpartum hemoglobin and hematocrit compared to oral iron supplementation only. Conclusions: Postpartum zinc supplementation causes a significant positive effect on postpartum depression (EPDS score ≥ 9). Zinc supplementation had a negative but transient influence on the hematological status in women with postpartum anemia treated with oral iron supplementation; however, the differences were not clinically significant. Thus, we did not regard it as an adverse effect to be considered, and postpartum zinc supplementation may be viewed as beneficial in postpartum women.

Zinc deficiency as a possible risk factor for increased susceptibility and severe progression of Corona Virus Disease 19

The importance of Zn for human health becomes obvious during Zn deficiency. Even mild insufficiencies of Zn cause alterations in haematopoiesis and immune functions, resulting in a proinflammatory phenotype and a disturbed redox metabolism. Although immune system malfunction has the most obvious effect, the functions of several tissue cell types are disturbed if Zn supply is limiting. Adhesion molecules and tight junction proteins decrease, while cell death increases, generating barrier dysfunction and possibly organ failure. Taken together, Zn deficiency both weakens the resistance of the human body towards pathogens and at the same time increases the danger of an overactive immune response that may cause tissue damage. The case numbers of Corona Virus Disease 19 (COVID-19) are still increasing, which is causing enormous problems for health systems and economies. There is an urgent need to reduce both the number of severe cases and the resulting deaths. While therapeutic options are still under investigation, and first vaccines have been approved, cost-effective ways to reduce the likelihood of or even prevent infection, and the transition from mild symptoms to more serious detrimental disease, are highly desirable. Nutritional supplementation might be an effective option to achieve these aims. In this review, we discuss known Zn deficiency effects in the context of an infection with Severe Acute Respiratory Syndrome-Coronavirus-2 and its currently known pathogenic mechanisms and elaborate on how severe pre-existing Zn deficiency may pre-dispose patients to a severe progression of COVID-19. First published clinical data on the association of Zn homoeostasis with COVID-19 and registered studies in progress are listed.

Analysis of 19 Minerals and Cortisol in Red Deer Hair in Two Different Areas of the Stelvio National Park: A Preliminary Study

Simple Summary

Minerals play an important role in animals’ health and nutritional status and are associated with cortisol, a hormone involved in several physiological processes and with a fundamental role in allostasis, the process of achieving homeostasis. The aim of the present study is to perform a preliminary investigation on the concentration of 19 minerals and cortisol in the hair of red deer coming from two different areas of the Stelvio National Park. Results showed a close association between hair minerals and cortisol concentrations and an effect of deer origin. Hair minerals and cortisol assessment is an easy, rapid, and low cost screening method and it is useful in wildlife management programs, in order to investigate wild animals’ health status, to perform environmental studies, to assess the presence of contaminants in wild species and to determine risks for humans. In addition, it could be helpful in public health programs to estimate contamination risks linked to wild animal meat consumption or to assess the presence of contaminants in food-producing animals.

Abstract

The aim of the study was to perform an investigation on the concentration of 19 minerals and cortisol in red deer (Cervus elaphus) hair, a matrix that is easy to collect with non-invasive and painless sampling, able to represent an integrative values of long-term substance concentrations, and able to give useful information, also when performed on dead animals, given its extreme stability over time. In the study thirty-five animals were included, coming from two different sides of a valley in the Stelvio National Park, where official water analysis had pointed out elevated concentrations of As in one of the two orographic sides. Hair cortisol concentrations were measured using a RIA(Radio Immuno Assay), while minerals were detected using ICP-MS (Inductively Coupled Plasma- Mass Spectrometry). Results showed a negative relationship between cortisol and some mineral concentrations (Li, Co, As, Cd, Cr and Tl) and significant differences in some mineral concentrations between park areas (Al, Co, Cu, Cd and Ni). As, Cr and cortisol differences approached statistical significance. This preliminary study represents a step forward in the study of wildlife allostatic load and a valid method for applications in wildlife management programs, in environmental studies and in public health programs.

Prenatal stress and the development of psychopathology: Lifestyle behaviors as a fundamental part of the puzzle

Maternal psychological stress, depression, and anxiety during pregnancy (prenatal stress; PNS) are thought to impact fetal development with long-term effects on offspring outcome. These effects would include physical and mental health, including psychopathology. Maternal sleep, diet, and exercise during pregnancy are lifestyle behaviors that are understudied and often solely included in PNS studies as confounders. However, there are indications that these lifestyle behaviors may actually constitute essential mediators between PNS and fetal programming processes. The goal of this theoretical review was to investigate this idea by looking at the evidence for associations between PNS and sleep, diet, and exercise, and by piecing together the information on potential underlying mechanisms and causal pathways through which these factors may affect the offspring. The analysis of the literature led to the conclusion that sleep, diet, and exercise during pregnancy, may have fundamental roles as mediators between PNS and maternal pregnancy physiology. By integrating these lifestyle behaviors into models of prenatal programming of development, a qualitatively higher and more comprehensive understanding of the prenatal origins of psychopathology can be obtained. The review finalizes by discussing some of the present challenges facing the field of PNS and offspring programming, and offering solutions for future research.

Association of Mood Disorders with Serum Zinc Concentrations in Adolescent Female Students

Among various factors influencing mood disorders, the impact of micronutrient deficiencies has attracted a great attention. Zinc deficiency is considered to play a crucial role in the onset and progression of mood disorders in different stages of life. The main objective of this study was to assess the correlation between serum zinc levels and mood disorders in high school female students. This cross-sectional study was conducted on a random sample of 100 representative high school female students. The participants completed 24-h food recall questionnaires to assess the daily zinc intakes. Serum zinc status was assessed using flame atomic absorption spectrometry, and zinc deficiency was defined accordingly. Mood disorders were estimated by calculating the sum of two test scores including Beck's depression inventory (BDI) and hospital anxiety depression scale (HADS) tests. General linear model (GLM) and Pearson's regression test were applied to show the correlation of serum zinc levels and mood disorder scores and the correlation between zinc serum levels and BDI scores, respectively. Dietary zinc intake was higher in subjects with normal zinc concentrations than that of zinc-deficient group (p = 0.001). Serum zinc levels were inversely correlated with BDI and HADS scores (p < 0.05). Each 10 μg/dL increment in serum zinc levels led to 0.3 and 0.01 decrease in depression and anxiety scores, respectively (p < 0.05). Serum zinc levels were inversely correlated with mood disorders including depression and anxiety in adolescent female students. Increasing serum levels of zinc in female students could improve their mood disorders.

Manganese intake is inversely associated with depressive symptoms during pregnancy in Japan: Baseline data from the Kyushu Okinawa Maternal and Child Health Study

BACKGROUND

One epidemiological study in Canada has addressed the association between zinc intake and depressive symptoms during pregnancy while another epidemiological study in Korea has examined the association between iron intake and depressive symptoms during pregnancy. The present cross-sectional study in Japan examined the association between intake of zinc, magnesium, iron, copper, and manganese and depressive symptoms during pregnancy.

METHODS

Study subjects were 1745 pregnant women. Dietary intake during the preceding month was assessed using a self-administered diet history questionnaire. Depressive symptoms were defined as a score ≥16 on the Center for Epidemiologic Studies Depression Scale. Adjustment was made for age, gestation, region of residence, number of children, family structure, history of depression, family history of depression, smoking, secondhand smoke exposure at home and at work, employment, household income, education, body mass index, and intake of saturated fatty acids, eicosapentaenoic acid plus docosahexaenoic acid, calcium, vitamin D, and isoflavones.

RESULTS

In crude analysis, significant inverse associations were observed between intake levels of zinc, magnesium, iron, copper, and manganese and the prevalence of depressive symptoms during pregnancy. After adjustment for confounding factors, only manganese intake was independently inversely associated with depressive symptoms during pregnancy: the adjusted prevalence ratio between extreme quartiles was 0.74 (95% confidence interval:0.56-0.97, P for trend=0.046).

LIMITATIONS

Information was obtained between the 5th and 39th week of pregnancy.

CONCLUSIONS

The current cross-sectional study of Japanese women demonstrated higher manganese intake to be independently associated with a lower prevalence of depressive symptoms during pregnancy.

The role of diet and nutritional supplementation in perinatal depression: a systematic review

This article presents a systematic literature review on whether dietary intake influences the risk for perinatal depression, i.e. depression during pregnancy or post-partum. Such a link has been hypothesized given that certain nutrients are important in the neurotransmission system and pregnancy depletes essential nutrients. PubMed, EMBASE and CINAHL databases were searched for relevant articles until 30 May 2015. We included peer-reviewed studies of any design that evaluated whether perinatal depression is related to dietary intake, which was defined as adherence to certain diets, food-derived intake of essential nutrients or supplements. We identified 4808 studies, of which 35 fulfilled inclusion criteria: six randomized controlled trials, 12 cohort, one case-control and 16 cross-sectional studies, representing 88 051 distinct subjects. Studies were grouped into four main categories based on the analysis of dietary intake: adherence to dietary patterns (nine studies); full panel of essential nutrients (six studies); specific nutrients (including B vitamins, Vitamin D, calcium and zinc; eight studies); and intake of fish or polyunsaturated fatty acids (PUFAs; 12 studies). While 13 studies, including three PUFA supplementation trials, found no evidence of an association, 22 studies showed protective effects from healthy dietary patterns, multivitamin supplementation, fish and PUFA intake, calcium, Vitamin D, zinc and possibly selenium. Given the methodological limitations of existing studies and inconsistencies in findings across studies, the evidence on whether nutritional factors influence the risk of perinatal depression is still inconclusive. Further longitudinal studies are needed, with robust and consistent measurement of dietary intake and depressive symptoms, ideally starting before pregnancy.

Zinc transporters protein level in postmortem brain of depressed subjects and suicide victims

BACKGROUND

Major depressive disorder (MDD) is a serious psychiatric illness, associated with an increasing rate of suicide. The pathogenesis of depression may be associated with the disruption of zinc (Zn) homeostasis. In the brain, several proteins that regulate Zn homeostasis are present, including Zn transporters (ZnTs) which remove Zn from the cytosol. The present study was designed to investigate whether depression and suicide are associated with alterations in the expression of the ZnTs protein.

METHODS

Protein levels of ZnT1, ZnT3, ZnT4, ZnT5 and ZnT6 were measured in postmortem brain tissue from two different cohorts. Cohort A contained 10 subjects diagnosed with MDD (7 were suicide victims) and 10 psychiatrically-normal control subjects and cohort B contained 11 non-diagnosed suicide victims and 8 sudden-death control subjects. Moreover, in cohort A we measured protein level of NMDA (GluN2A subunit), AMPA (GluA1 subunit) and 5-HT1A receptors and PSD-95. Proteins were measured in the prefrontal cortex (PFC) using Western blotting. In addition, Zn concentration was measured using a voltammetric method.

RESULTS

There was a significant increase in protein levels of ZnT1, ZnT4, ZnT5 in the PFC in MDD, relative to control subjects, while ZnT3 protein level was decreased in MDD. There was no significant difference in the Zn concentration in the PFC between control and MDD subjects. Similarly, in the PFC of suicide victims (non-diagnosed), an increase in protein levels of ZnT1, ZnT4, ZnT5 and ZnT6 was observed. Conversely, protein levels of ZnT3 were decreased in both suicide victims and subjects with MDD, in comparison with control subjects. There was also a significant decrease in the protein level of GluA1, GluN2A, PSD-95 and 5-HT1A in MDD.

CONCLUSIONS

Our studies suggest that alterations in Zn transport proteins are associated with the pathophysiology of MDD and suicide.

Serum zinc concentrations and depression in persons with Human Immunodeficiency Virus infection: The positive living with HIV (POLH) study

Low levels of serum zinc concentrations and depression are common in persons infected with Human Immunodeficiency Virus (HIV). Low levels of serum zinc concentrations may increase risk of depression in general population. However, research on the role of zinc in depression among HIV- infected person is limited. We assessed the association between serum zinc concentrations and depression in HIV-infected persons. A cross-sectional survey was conducted among 311 HIV-positive people (177 men and 134 women) aged 18-60 years residing in Kathmandu, Nepal. The atomic absorption method was used to measure serum zinc concentrations and the Beck Depression Inventory (BDI)-Ia method was used to measure depression, with cut off score 20 or higher consistent with clinically significant depression. Relationships were assessed using multiple linear and logistic regression analyses. Serum zinc concentrations were significantly inversely associated with depression in all participants and in men but not in women. Participants with the highest tertile of serum zinc concentrations had a significantly decreased risk of depression in men but not in women. Serum zinc concentrations were inversely associated with depressive symptoms scores in HIV-infected men. Further prospective studies are needed to confirm the role of zinc in depression among persons infected with HIV.

Lower Serum Zinc and Higher CRP Strongly Predict Prenatal Depression and Physio-somatic Symptoms, Which All Together Predict Postnatal Depressive Symptoms

Pregnancy and delivery are associated with activation of immune-inflammatory pathways which may prime parturients to develop postnatal depression. There are, however, few data on the associations between immune-inflammatory pathways and prenatal depression and physio-somatic symptoms. This study examined the associations between serum zinc, C-reactive protein (CRP), and haptoglobin at the end of term and prenatal physio-somatic symptoms (fatigue, back pain, muscle pain, dyspepsia, obstipation) and prenatal and postnatal depressive and anxiety symptoms as measured using the Edinburgh Postnatal Depression Scale (EPDS), Beck Depression Inventory (BDI), Hamilton Depression Rating Scale (HAMD), and Spielberger's State Anxiety Inventory (STAI). Zinc and haptoglobin were significantly lower and CRP increased at the end of term as compared with non-pregnant women. Prenatal depression was predicted by lower zinc and lifetime history of depression, anxiety, and premenstrual tension syndrome (PMS). The latter histories were also significantly and inversely related to lower zinc. The severity of prenatal EDPS, HAMD, BDI, STAI, and physio-somatic symptoms was predicted by fatigue in the first and second trimesters, a positive life history of depression, anxiety, and PMS, and lower zinc and higher CRP. Postnatal depressive symptoms are predicted by prenatal depression, physio-somatic symptoms, zinc and CRP. Prenatal depressive and physio-somatic symptoms have an immune-inflammatory pathophysiology, while postnatal depressive symptoms are highly predicted by prenatal immune activation, prenatal depression, and a lifetime history of depression and PMS. Previous episodes of depression, anxiety disorders, and PMS may prime pregnant females to develop prenatal and postnatal depressive symptoms via activated immune pathways.

Activation of mTOR dependent signaling pathway is a necessary mechanism of antidepressant-like activity of zinc

The rapid antidepressant response to the N-methyl-D-aspartate (NMDA) receptor antagonists is mediated by activation of the mammalian target of the rapamycin (mTOR) signaling pathway, an increase in the synthesis of synaptic proteins and formation of new synapses in the prefrontal cortex (PFC) of rats. Zinc (Zn), which is a potent NMDA receptor antagonist, exerts antidepressant-like effects in screening tests and models of depression. We focused these studies in investigating whether activation of the mTOR signaling pathway is also a necessary mechanism of the antidepressant-like activity of Zn. We observed that a single injection of Zn (5 mg/kg) induced an increase in the phosphorylation of mTOR and p70S6K 30 min and 3 h after Zn treatment at time points when Zn produced also an antidepressant-like effect in the forced swim test (FST). Furthermore, Zn administered 3 h before the decapitation increased the level of brain derived neurotrophic factor (BDNF), GluA1 and synapsin I. An elevated level of GluA1 and synapsin I was still observed 24 h after the Zn treatment, although Zn did not produce any effects in the FST at that time point. We also observed that pretreatment with rapamycin (mTORC1 inhibitor), LY294002 (PI3K inhibitor), H-89 (PKA inhibitor) and GF109203X (PKC inhibitor) blocked the antidepressant-like effect of Zn in FST in rats and blocks Zn-induced activation of mTOR signaling proteins (analyzed 30 min after Zn administration). These studies indicated that the antidepressant-like activity of Zn depends on the activation of mTOR signaling and other signaling pathways related to neuroplasticity, which can indirectly modulate mTOR function.

The association between diet quality and mental health during the perinatal period. A systematic review

BACKGROUND

While maternal nutrition during pregnancy is known to play a critical role in the health of both mother and offspring, the magnitude of this association has only recently been realized. Novel, epigenetic data suggest that maternal dietary intake has permanent phenotypic consequences for offspring, highlighting the potency of antenatal diet. To date, the relationship between poor antenatal diet and maternal mental health specifically, remains poorly understood. Therefore, we aimed to systematically review evidence that has examined associations between antenatal diet quality and the experience of depressive, anxiety and stress symptoms during the perinatal period.

METHODS

A search for peer-reviewed papers was conducted using Medline Complete, PsycINFO, CINAHL, Academic Search Premiere and Psychology and Behavioral Science Collection.

RESULTS

Nine studies (cohort = 4, cross-sectional = 5) published between 2005 and 2013 were eligible for inclusion in this review. A synthesis of findings revealed positive associations between poor quality and unhealthy diets and antenatal depressive and stress symptoms. Healthy diets were inversely associated with antenatal depressive and anxiety symptoms. Postnatal depressive symptoms demonstrated inconsistent results.

CONCLUSIONS

Given the paucity of research examining diet quality and mental health in women during the perinatal period, further sufficiently powered studies are urgently required to examine this association.

Low dietary intake of magnesium is associated with increased externalising behaviours in adolescents

OBJECTIVE

Adequate Zn and Mg intakes may be beneficial for the prevention and treatment of mental health problems, such as depression, anxiety and attention-deficit hyperactivity disorder. We aimed to investigate the prospective association between dietary intakes of Zn and Mg and internalising and externalising behaviour problems in a population-based cohort of adolescents.

DESIGN

Prospective analysis (general linear mixed models) of dietary intakes of Zn and Mg assessed using a validated FFQ and mental health symptoms assessed using the Youth Self-Report (YSR), adjusting for sex, physical activity, family income, supplement status, dietary misreporting, BMI, family functioning and energy intake.

SETTING

Western Australian Pregnancy Cohort (Raine) Study.

SUBJECTS

Adolescents (n 684) at the 14- and 17-year follow-ups.

RESULTS

Higher dietary intake of Mg (per SD increase) was significantly associated with reduced externalising behaviours (β = -1.45; 95% CI -2.40, -0.50; P = 0.003). There was a trend towards reduced externalising behaviours with higher Zn intake (per SD increase; β = -0.73; 95% CI -1.57, 0.10; P = 0.085).

CONCLUSIONS

The study shows an association between higher dietary Mg intake and reduced externalising behaviour problems in adolescents. We observed a similar trend, although not statistically significant, for Zn intake. Randomised controlled trials are necessary to determine any benefit of micronutrient supplementation in the prevention and treatment of mental health problems in adolescents.

Biological consequences of zinc deficiency in the pathomechanisms of selected diseases

From many points of view, zinc is one of the most important trace elements in biological systems. Many articles describe the well-known role of this metal in human physiology and pathophysiology, but in the related literature, there is a lack of current and reliable reviews of the role of zinc deficiency in many diseases. In this article, we describe the role of zinc deficiency in the oxidative stress control, immune response, proliferation, and pathogenesis and pathophysiology of selected diseases such as depression, cardiovascular diseases, diabetes mellitus, Alzheimer's disease, and Wilson's disease.

Dietary zinc is associated with a lower incidence of depression: findings from two Australian cohorts

BACKGROUND

Several animal and human studies have shown that zinc plays a role in reducing depression, but there have been no longitudinal studies in both men and women on this topic. The aim of this study was to investigate dietary zinc, and the zinc to iron ratio, as predictors of incident depression in two large longitudinal studies of mid-age and older Australians.

METHODS

Data were self-reported, as part of the Australian Longitudinal Study on Women׳s Health (women aged 50-61 years) and Hunter Community Study (men and women aged 55-85 years). Validated food frequency questionnaires were used to assess dietary intake. Energy-adjusted zinc was ranked using quintiles and predictors of incident depression were examined using multivariate logistic regression.

RESULTS

Both studies showed an inverse association between dietary zinc intake and risk of depression, even after adjusting for potential confounders. Compared to those with the lowest zinc intake those with the highest zinc intake had significantly lower odds of developing depression with a reduction of about 30-50%. There was no association between the zinc to iron ratio and developing depression in either study.

LIMITATIONS

Dietary assessment was carried out only at baseline and although adjustments were made for all known potential confounders, residual confounding cannot be entirely excluded.

CONCLUSIONS

Low dietary zinc intake is associated with a greater incidence of depression in both men and women, as shown in two prospective cohorts. Further studies into the precise role of zinc compared to other important nutrients from the diet are needed.

Lifestyle management of unipolar depression

OBJECTIVE

To be used in conjunction with 'Pharmacological management of unipolar depression' [Malhi et al. Acta Psychiatr Scand 2013;127(Suppl. 443):6-23] and 'Psychological management of unipolar depression' [Lampe et al. Acta Psychiatr Scand 2013;127(Suppl. 443):24-37]. To provide clinically relevant recommendations for lifestyle modifications in depression, derived from a literature review.

METHOD

A search of pertinent literature was conducted up to August 2012 in the area of lifestyle factors and depression. A narrative review was then conducted.

RESULTS

There is evidence that level of physical activity plays a role in the risk of depression, and there is a large and validated evidence base for exercise as a therapeutic modality. Smoking and alcohol and substance misuse appear to be independent risk factors for depression, while the new epidemiological evidence supports the contention that diet is a risk factor for depression; good quality diets appear protective and poor diets increase risk.

CONCLUSION

Lifestyle modification, with a focus on exercise, diet, smoking and alcohol, may be of substantial value in reducing the burden of depression in individuals and the community.

Dietary zinc intake and the risk of depression in middle-aged men: a 20-year prospective follow-up study

BACKGROUND

Zinc is an immunomodulatory trace element suggested to be beneficial in the augmentation of antidepressant therapy. Cross-sectional studies have also suggested an association between low dietary zinc and depression. This study examined the association between dietary zinc intake and depression in a prospective setting in initially depression-free men during a 20-year follow-up.

METHODS

The study formed a part of the population-based Kuopio Ischemic Heart Disease Risk Factor (KIHD) Study, and comprised 2317 Finnish men aged 42-61 years. Zinc intake was assessed at baseline by a 4-d food record. Baseline depression severity was recorded with the Human Population Laboratory Depression Scale. In the prospective setting, depression was defined as having received a hospital discharge diagnosis of unipolar depressive disorder. Individuals who at baseline had elevated depressive symptoms were excluded (n=283).

RESULTS

Altogether, 60 (2.7%) individuals received a hospital discharge diagnosis of depression during the 20-year follow-up. In Cox regression analysis adjusted for age, baseline depression severity, smoking, alcohol use, physical exercise and the use of dietary supplements, belonging to the lowest tertile of energy-adjusted zinc intake was not associated with an increased depression risk (RR 1.06, 95% CI 0.59-1.90).

LIMITATIONS

These observations may not be generalizable to women, or to individuals with a depression level not warranting hospitalization.

CONCLUSIONS

Our findings suggest that a low dietary zinc intake may not longitudinally precede depression in men. Dietary zinc intake may not have relevance for the prevention of depression in middle-aged men with a sufficient dietary zinc intake.

Zinc homeostasis and neurodegenerative disorders

Zinc is an essential trace element, whose importance to the function of the central nervous system (CNS) is increasingly being appreciated. Alterations in zinc dyshomeostasis has been suggested as a key factor in the development of several neuropsychiatric disorders. In the CNS, zinc occurs in two forms: the first being tightly bound to proteins and, secondly, the free, cytoplasmic, or extracellular form found in presynaptic vesicles. Under normal conditions, zinc released from the synaptic vesicles modulates both ionotropic and metabotropic post-synaptic receptors. While under clinical conditions such as traumatic brain injury, stroke or epilepsy, the excess influx of zinc into neurons has been found to result in neurotoxicity and damage to postsynaptic neurons. On the other hand, a growing body of evidence suggests that a deficiency, rather than an excess, of zinc leads to an increased risk for the development of neurological disorders. Indeed, zinc deficiency has been shown to affect neurogenesis and increase neuronal apoptosis, which can lead to learning and memory deficits. Altered zinc homeostasis is also suggested as a risk factor for depression, Alzheimer's disease (AD), aging, and other neurodegenerative disorders. Under normal CNS physiology, homeostatic controls are put in place to avoid the accumulation of excess zinc or its deficiency. This cellular zinc homeostasis results from the actions of a coordinated regulation effected by different proteins involved in the uptake, excretion and intracellular storage/trafficking of zinc. These proteins include membranous transporters (ZnT and Zip) and metallothioneins (MT) which control intracellular zinc levels. Interestingly, alterations in ZnT and MT have been recently reported in both aging and AD. This paper provides an overview of both clinical and experimental evidence that implicates a dysfunction in zinc homeostasis in the pathophysiology of depression, AD, and aging.

Placental Corticotropin-Releasing Hormone Mediates the Association Between Prenatal Social Support and Postpartum Depression

Three decades of research point to both biological and psychological risk factors for postpartum depression, but very little research integrates the two. This study bridged this gap by testing whether prenatal social support predicted depressive symptoms at 8 weeks postpartum in a multiethnic sample of 210 women and whether the stress hormone placental corticotropin-releasing hormone (pCRH), measured at 19, 29, and 37 weeks' gestation, mediated this relationship. We found that prenatal family support predicted significantly fewer depressive symptoms postpartum and more gradual increases in pCRH from 29 to 37 weeks' gestation. Furthermore, steeper increases in pCRH during this same period predicted more depressive symptoms postpartum. Finally, these changes in pCRH in late pregnancy mediated the relationship between prenatal family support and postpartum depressive symptoms. These results suggest that social and biological risk factors for postpartum depressive symptoms are intertwined and move us closer to an integrated biopsychosocial understanding of postpartum depression.

Cross-sectional relationship between chronic stress and mineral concentrations in hair of elementary school girls

Chronic stress exposure is associated with diverse negative health outcomes. It has been hypothesised that stress may also negatively affect the body's mineral status. This study investigates the association between chronic stress and long-term mineral concentrations of calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), phosphorus (P) and zinc (Zn) in scalp hair among elementary school girls. Complete information on child-reported stress estimates (Coddington Life Events Scale (CLES)), hair cortisone and hair mineral concentrations, and predefined confounders in the stress-mineral relationship (i.e. age, body mass index, physical activity, diet, hair colour and parental education) was provided cross-sectionally for 140 girls (5-10 years old). The relationship between childhood stress measures (predictor) and hair minerals (outcome) was studied using linear regression analysis, adjusted for the abovementioned confounders. Hair cortisone concentrations were inversely associated with hair mineral concentrations of Ca, Mg, Zn and the Ca/P ratio. Children at risk by life events (CLES) presented an elevated Ca/Mg ratio. These findings were persistent after adjustment for confounders. This study demonstrated an independent association between chronic stress measures and hair mineral levels in young girls, indicating the importance of physiological stress-mineral pathways independently from individual or behavioural factors. Findings need to be confirmed in a more heterogeneous population and on longitudinal basis. The precise mechanisms by which stress alters hair mineral levels should be further elucidated.

Inflammatory cytokines in depression: neurobiological mechanisms and therapeutic implications

Mounting evidence indicates that inflammatory cytokines contribute to the development of depression in both medically ill and medically healthy individuals. Cytokines are important for development and normal brain function, and have the ability to influence neurocircuitry and neurotransmitter systems to produce behavioral alterations. Acutely, inflammatory cytokine administration or activation of the innate immune system produces adaptive behavioral responses that promote conservation of energy to combat infection or recovery from injury. However, chronic exposure to elevated inflammatory cytokines and persistent alterations in neurotransmitter systems can lead to neuropsychiatric disorders and depression. Mechanisms of cytokine behavioral effects involve activation of inflammatory signaling pathways in the brain that results in changes in monoamine, glutamate, and neuropeptide systems, and decreases in growth factors, such as brain-derived neurotrophic factor. Furthermore, inflammatory cytokines may serve as mediators of both environmental (e.g. childhood trauma, obesity, stress, and poor sleep) and genetic (functional gene polymorphisms) factors that contribute to depression's development. This review explores the idea that specific gene polymorphisms and neurotransmitter systems can confer protection from or vulnerability to specific symptom dimensions of cytokine-related depression. Additionally, potential therapeutic strategies that target inflammatory cytokine signaling or the consequences of cytokines on neurotransmitter systems in the brain to prevent or reverse cytokine effects on behavior are discussed.

Potential roles of zinc in the pathophysiology and treatment of major depressive disorder

Incomplete response to monoaminergic antidepressants in major depressive disorder (MDD), and the phenomenon of neuroprogression, suggests a need for additional pathophysiological markers and pharmacological targets. Neuronal zinc is concentrated exclusively within glutamatergic neurons, acting as an allosteric modulator of the N-methyl D-aspartate and other receptors that regulate excitatory neurotransmission and neuroplasticity. Zinc-containing neurons form extensive associational circuitry throughout the cortex, amygdala and hippocampus, which subserve mood regulation and cognitive functions. In animal models of depression, zinc is reduced in these circuits, zinc treatment has antidepressant-like effects and dietary zinc insufficiency induces depressive behaviors. Clinically, serum zinc is lower in MDD, which may constitute a state-marker of illness and a risk factor for treatment-resistance. Marginal zinc deficiency in MDD may relate to multiple putative mechanisms underlying core symptomatology and neuroprogression (e.g. immune dysfunction, monoamine metabolism, stress response dysregulation, oxidative/nitrosative stress, neurotrophic deficits, transcriptional/epigenetic regulation of neural networks). Initial randomized trials suggest a benefit of zinc supplementation. In summary, molecular and animal behavioral data support the clinical significance of zinc in the setting of MDD.

Nutrient intakes and the common mental disorders in women

BACKGROUND

There is an increasing recognition of the role of nutrition in depression and anxiety. Magnesium, folate and zinc have all been implicated in depressive illness, however there are few data on these nutrients in anxiety disorders and the data from population-studies are limited.

AIMS

In a large, randomly-selected, population-based sample of women, this study aimed to examine the relationship between the dietary intakes of these three micronutrients and clinically determined depressive and anxiety disorders and symptoms.

METHODS

Nutrient intakes were determined using a validated food frequency questionnaire. The General Health Questionnaire-12 measured psychological symptoms, and a clinical interview (Structured Clinical Interview for DSM-IV-TR, non-patient edition) assessed current depressive and anxiety disorders.

RESULTS

After adjustments for energy intake, each standard deviation increase in the intake of zinc, magnesium and folate was associated with reduced odds ratio (OR) for major depression/dysthymia (zinc: OR=0.52, 95% confidence interval (CI) 0.31 to 0.88; magnesium: OR=0.60, 95% CI 0.37 to 0.96; folate: OR=0.66, 95% CI 0.45 to 0.97). There was also an inverse association between the intake of magnesium and zinc and GHQ-12 scores (zinc: zβ=-0.16, 95% CI -0.29 to -0.04; magnesium: -0.14, 95% CI -0.26 to -0.03). These relationships were not confounded by age, socioeconomic status, education or other health behaviours. There was no relationship observed between any nutrient and anxiety disorders.

CONCLUSION

These results demonstrate an association between the dietary intakes of magnesium, folate and zinc and depressive illnesses, although reverse causality and/or confounding cannot be ruled out as explanations.

Zinc in the central nervous system: From molecules to behavior

The trace metal zinc is a biofactor that plays essential roles in the central nervous system across the lifespan from early neonatal brain development through the maintenance of brain function in adults. At the molecular level, zinc regulates gene expression through transcription factor activity and is responsible for the activity of dozens of key enzymes in neuronal metabolism. At the cellular level, zinc is a modulator of synaptic activity and neuronal plasticity in both development and adulthood. Given these key roles, it is not surprising that alterations in brain zinc status have been implicated in a wide array of neurological disorders including impaired brain development, neurodegenerative disorders such as Alzheimer's disease, and mood disorders including depression. Zinc has also been implicated in neuronal damage associated with traumatic brain injury, stroke, and seizure. Understanding the mechanisms that control brain zinc homeostasis is thus critical to the development of preventive and treatment strategies for these and other neurological disorders.