A decline in inflammation is associated with less depressive symptoms after a dietary intervention in metabolic syndrome patients: a longitudinal study

Peripheral inflammation associated with depression and reduced weight loss: a longitudinal study of bariatric patients

BACKGROUND

Research implicates inflammation in the vicious cycle between depression and obesity, yet few longitudinal studies exist. The rapid weight loss induced by bariatric surgery is known to improve depressive symptoms dramatically, but preoperative depression diagnosis may also increase the risk for poor weight loss. Therefore, we investigated longitudinal associations between depression and inflammatory markers and their effect on weight loss and clinical outcomes in bariatric patients.

METHODS

This longitudinal observational study of 85 patients with obesity undergoing bariatric surgery included 41 cases with depression and 44 controls. Before and 6 months after surgery, we assessed depression by clinical interview and measured serum high-sensitivity C-reactive protein (hsCRP) and inflammatory cytokines, including interleukin (IL)-6 and IL-10.

RESULTS

Before surgery, depression diagnosis was associated with significantly higher serum hsCRP, IL-6, and IL-6/10 ratio levels after controlling for confounders. Six months after surgery, patients with pre-existing depression still had significantly higher inflammation despite demonstrating similar weight loss to controls. Hierarchical regression showed higher baseline hsCRP levels predicted poorer weight loss (β = -0.28, p = 0.01) but had no effect on depression severity at follow-up (β = -0.02, p = 0.9). Instead, more severe baseline depressive symptoms and childhood emotional abuse predicted greater depression severity after surgery (β = 0.81, p < 0.001; and β = 0.31, p = 0.001, respectively).

CONCLUSIONS

Depression was significantly associated with higher inflammation beyond the effect of obesity and other confounders. Higher inflammation at baseline predicted poorer weight loss 6 months after surgery, regardless of depression diagnosis. Increased inflammation, rather than depression, may drive poor weight loss outcomes among bariatric patients.

Efficacy of low carbohydrate and ketogenic diets in treating mood and anxiety disorders: systematic review and implications for clinical practice

BACKGROUND

There is mounting interest in the potential efficacy of low carbohydrate and very low carbohydrate ketogenic diets in various neurological and psychiatric disorders.

AIMS

To conduct a systematic review and narrative synthesis of low carbohydrate and ketogenic diets (LC/KD) in adults with mood and anxiety disorders.

METHOD

MEDLINE, Embase, PsycINFO and Cochrane databases were systematically searched for articles from inception to 6 September 2022. Studies that included adults with any mood or anxiety disorder treated with a low carbohydrate or ketogenic intervention, reporting effects on mood or anxiety symptoms were eligible for inclusion. PROSPERO registration CRD42019116367.

RESULTS

The search yielded 1377 articles, of which 48 were assessed for full-text eligibility. Twelve heterogeneous studies (stated as ketogenic interventions, albeit with incomplete carbohydrate reporting and measurements of ketosis; diet duration: 2 weeks to 3 years; n = 389; age range 19 to 75 years) were included in the final analysis. This included nine case reports, two cohort studies and one observational study. Data quality was variable, with no high-quality evidence identified. Efficacy, adverse effects and discontinuation rates were not systematically reported. There was some evidence for efficacy of ketogenic diets in those with bipolar disorder, schizoaffective disorder and possibly unipolar depression/anxiety. Relapse after discontinuation of the diet was reported in some individuals.

CONCLUSIONS

Although there is no high-quality evidence of LC/KD efficacy in mood or anxiety disorders, several uncontrolled studies suggest possible beneficial effects. Robust studies are now needed to demonstrate efficacy, to identify clinical groups who may benefit and whether a ketogenic diet (beyond low carbohydrate) is required and to characterise adverse effects and the risk of relapse after diet discontinuation.

Does Better Diet Quality Offset the Association between Depression and Metabolic Syndrome?

Several studies have shown that depression increases the risk of metabolic syndrome (MetS), which is often exacerbated by the fact that both exist concurrently. People with depression are more likely to have unhealthy eating habits, which can eventually trigger the development of MetS. This study was to investigate whether diet quality modifies the association between depression and MetS in a total of 13,539 Korean adults aged 19 to 80 from 2014, 2016 and 2018 Korean National Health and Nutrition Examination Surveys. Depression was assessed by the Patient Health Questionnaire-9 (PHQ-9) and subjects were divided into subgroups according to the PHQ-9 scores: normal (<5), mild (5-9), and moderate-to-severe (≥10) groups. Diet quality was measured by the Korean Healthy Eating Index (KHEI). A complex sample multiple logistic regression stratified by tertiles of KHEI scores was used to explore whether diet quality modifies an association between depression severity and metabolic syndrome. Depression severity was positively associated with the risk of MetS (p trend = 0.006) after adjustment for potential confounders. Only the lowest diet quality, moderately-to-severely depressed group, showed a higher risk of MetS (OR: 1.72, 95% CI: 1.24-2.40) compared to the normal group. Our results suggest that healthy diet quality could offset the positive relationship between depression and MetS in the general Korean adult population. Encouraging a healthy diet regime can improve not only physical health but also the mental state of the general public.

TNF-α Mediates the Association between Dietary Inflammatory Index and Depressive Symptoms in Breast Cancer

This study examined the association between the energy-adjusted Dietary Inflammatory Index (E-DII)-based dietary inflammatory potential and depressive symptoms (DepS) among patients with breast cancer and explores whether systemic inflammation mediates this association. We assessed dietary intake and DepS in 220 breast cancer patients by three 24 h dietary recalls and the Center for Epidemiological Studies Depression Scale (CES-D), respectively, and determined plasma levels of C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and interleukin (IL)-1β, IL-4, and IL-6 in 123 blood samples. We found that each one-point increase of E-DII was related to a 53% elevated risk of DepS. Patients with the most pro-inflammatory diets had a 5.13 times higher risk of DepS than those with the most anti-inflammatory diets. Among the E-DII components, vitamin B₂, zinc, and iron were inversely associated with DepS risk. Furthermore, E-DII scores were positively associated with CRP and TNF-α. Higher levels of TNF-α and IL-6 were associated with higher DepS risk. A significant mediating effect of TNF-α was revealed between E-DII and DepS. Our findings suggest that a pro-inflammatory diet is positively associated with breast cancer-related DepS, which may be mediated by TNF-α.

Determination of the relationship between dietary inflammatory index and depression status in female students

Background: The relationship between diet, inflammation and mental health has been receiving increasing interest. However, limited data are available on the inflammatory role of diet in university students, among whom depression is commonly observed. Aim: The aim of our study is to investigate the relationship between dietary inflammatory index (DII) and depression among female students of nutrition and dietetics department, whom we assume to be conscious about health. Methods: DII scores were determined by averaging the 3-day dietary records. Depression status of the students was determined by using Beck Depression Inventory (BDI). Results: Our study was conducted with 122 female university students. The mean total BDI score of the students in the first tertile (more anti-inflammatory effect) was found significantly lower than those of the students in the second and third tertiles (p = 0.001). In addition, there were no significant difference between the depression scores of the students and their grade level (p = 0.114) and place of residence (p = 0.866). We found a positive association between DII and depressive symptoms (Model 1, B = 0.512, %95 CI: 0.236-0.789, p = 0.000). This relationship was also found when adjusting for age, weight, body mass index, smoking status, and presence of chronic disease (Model 2, B = 0.496, %95 CI: 0.217-0.776, p = 0.006; Model 3, B = 0.493, %95 CI: 0.210-0.777, p = 0.024. Conclusion: Supporting that the inflammatory burden of diet is associated with mental health, our findings are of significance for the development of anti-inflammatory nutritional approaches among students who are prone to depression.

The influence of comorbid depression and overweight status on peripheral inflammation and cortisol levels

BACKGROUND

Depression and overweight are each associated with abnormal immune system activation. We sought to disentangle the extent to which depressive symptoms and overweight status contributed to increased inflammation and abnormal cortisol levels.

METHODS

Participants were recruited through the Wellcome Trust NIMA Consortium. The sample of 216 participants consisted of 69 overweight patients with depression; 35 overweight controls; 55 normal-weight patients with depression and 57 normal-weight controls. Peripheral inflammation was measured as high-sensitivity C-Reactive Protein (hsCRP) in serum. Salivary cortisol was collected at multiple points throughout the day to measure cortisol awakening response and diurnal cortisol levels.

RESULTS

Overweight patients with depression had significantly higher hsCRP compared with overweight controls (p = 0.042), normal-weight depressed patients (p < 0.001) and normal-weight controls (p < 0.001), after controlling for age and gender. Multivariable logistic regression showed that comorbid depression and overweight significantly increased the risk of clinically elevated hsCRP levels ⩾3 mg/L (OR 2.44, 1.28-3.94). In a separate multivariable logistic regression model, overweight status contributed most to the risk of having hsCRP levels ⩾3 mg/L (OR 1.52, 0.7-2.41), while depression also contributed a significant risk (OR 1.09, 0.27-2). There were no significant differences between groups in cortisol awakening response and diurnal cortisol levels.

CONCLUSION

Comorbid depression and overweight status are associated with increased hsCRP, and the coexistence of these conditions amplified the risk of clinically elevated hsCRP levels. Overweight status contributed most to the risk of clinically elevated hsCRP levels, but depression also contributed to a significant risk. We observed no differences in cortisol levels between groups.

Associations between Demographic Characteristics, Lifestyle Factors and School-Related Conditions and Symptoms of Mental Health Problems in Norwegian Upper Secondary School Students

Background: The purpose of this study was to evaluate the associations between demographic characteristics, lifestyle factors and school-related conditions, and symptoms of mental health problems in Norwegian upper secondary school students following the COVID-19 pandemic. Methods: In this cross-sectional study design we used a binary logistic regression model to evaluate potential associations between the predictors and dependent variable. Results: The following six predictors had a statistically significant impact on symptoms of mental health problems; gender effect of being a girl (p < 0.001), self-perceived body image (p < 0.001), sleep problems (p < 0.001), dietary habits (p = 0.033), school satisfaction (p = 0.013), and satisfaction with physical education (PE) class participation (p = 0.025). Conclusions: Being a girl was associated with a 315% higher probability of reporting symptoms of mental health problems than boys, whereas one unit increase in sleep problems showed a 192% higher probability of symptoms of mental health problems. Furthermore, a one unit increase on the respective beneficial predictors’ scales was associated with the following percentage having a lower probability of reporting symptoms of mental health problems; self-perceived body image (59%), dietary habits (58%), school satisfaction (82%), and satisfaction with PE class participation (68%).

Dietary patterns and internalizing symptoms in children and adolescents: A meta-analysis

CONTEXT

Studies of child and adolescent internalizing symptoms and dietary pattern have produced mixed results.

OBJECTIVES

To quantify the association between dietary patterns and internalizing symptoms, including depression, in children and adolescents.

DATA SOURCES

Embase, PsycINFO, MEDLINE, Web of Science and Cochrane up to March 2021.

STUDY SELECTION

Observational studies and randomized controlled trials with mean age ⩽ 18 years, reporting associations between diet patterns and internalizing symptoms.

DATA EXTRACTION

Mean effect sizes and 95% confidence intervals were determined under a random-effects model.

RESULTS

Twenty-six studies were cross-sectional, 12 were prospective, and 1 used a case-control design. The total number of participants enrolled ranged from 73,726 to 116,546. Healthy dietary patterns were negatively associated with internalizing (r = -0.07, p < 0.001, 95% confidence interval [-0.12, 0.06]) and depressive symptoms (r = -0.10, p < 0.001, 95% confidence interval [-0.18, -0.08]). Effect sizes were larger for studies of healthy dietary patterns and internalizing and depressive symptoms using self-report versus parent-report measures, as well as in cross-sectional studies of healthy dietary patterns and depression compared to prospective studies. Unhealthy dietary patterns were positively associated with internalizing (r = 0.09, p < 0.001, 95% confidence interval [0.06, 0.14]) and depressive symptoms (r = 0.10, p < 0.01, 95% CI [0.05, 0.17]). Larger effect sizes were observed for studies of unhealthy dietary patterns and internalizing and depressive symptoms using self-report versus parent-report measures.

LIMITATIONS

A lack of studies including clinical samples and/or physician diagnosis, and a paucity of studies in which anxiety symptoms were the primary mental health outcome.

CONCLUSION

Greater depression and internalizing symptoms are associated with greater unhealthy dietary patterns and with lower healthy dietary intake among children and adolescents.

Does Neuroinflammation Underlie the Cognitive Changes Observed With Dietary Interventions?

Dietary interventions, such as calorie restriction and ketogenic diet, have been extensively studied in ageing research, including in cognitive decline. Epidemiological studies indicate beneficial effects of certain dietary regimes on mental health, including mood disorders and dementia. However, randomised-controlled trials (the gold-standard of evidence-based medicine) on calorie restriction diets and the ketogenic diet have yet to show clinically convincing effects in neuropsychiatric disorders. This review will examine the quality of studies and evidence base for the ketogenic and calorie restriction diets in common neuropsychiatric conditions, collating findings from preclinical experiments, case reports or small clinical studies, and randomised controlled clinical trials. The major cellular mechanisms that mediate the effects of these dietary interventions on brain health include neuroinflammation, neuroprotection, and neuromodulation. We will discuss the studies that have investigated the roles of these pathways and their interactions. Popularity of the ketogenic and calorie restriction diets has grown both in the public domain and in psychiatry research, allowing for informed review of the efficacy, the limitations, and the side effects of these diets in specific patient populations. In this review we will summarise the clinical evidence for these diets in neuropsychiatry and make suggestions to improve clinical translation of future research studies.

Epigenetic signatures underlying inflammation: an interplay of nutrition, physical activity, metabolic diseases, and environmental factors for personalized nutrition

AIM AND OBJECTIVE

Emerging translational evidence suggests that epigenetic alterations (DNA methylation, miRNA expression, and histone modifications) occur after external stimuli and may contribute to exacerbated inflammation and the risk of suffering several diseases including diabetes, cardiovascular diseases, cancer, and neurological disorders. This review summarizes the current knowledge about the harmful effects of high-fat/high-sugar diets, micronutrient deficiencies (folate, manganese, and carotenoids), obesity and associated complications, bacterial/viral infections, smoking, excessive alcohol consumption, sleep deprivation, chronic stress, air pollution, and chemical exposure on inflammation through epigenetic mechanisms. Additionally, the epigenetic phenomena underlying the anti-inflammatory potential of caloric restriction, n-3 PUFA, Mediterranean diet, vitamin D, zinc, polyphenols (i.e., resveratrol, gallic acid, epicatechin, luteolin, curcumin), and the role of systematic exercise are discussed.

METHODS

Original and review articles encompassing epigenetics and inflammation were screened from major databases (including PubMed, Medline, Science Direct, Scopus, etc.) and analyzed for the writing of the review paper.

CONCLUSION

Although caution should be exercised, research on epigenetic mechanisms is contributing to understand pathological processes involving inflammatory responses, the prediction of disease risk based on the epigenotype, as well as the putative design of therapeutic interventions targeting the epigenome.

The Association Between Vascular Inflammation and Depressive Disorder. Causality, Biomarkers and Targeted Treatment

Diabetes, obesity, atherosclerosis, and myocardial infarction are frequently co-morbid with major depressive disorder. In the current review, it is argued that vascular inflammation is a factor that is common to all disorders and that an endothelial dysfunction of the blood-brain barrier could be involved in the induction of depression symptoms. Biomarkers for vascular inflammation include a high plasma level of C-reactive protein, soluble cell-adhesion molecules, von Willebrand factor, aldosterone, and proinflammatory cytokines like interleukin-6 or tumor necrosis factor α. A further possible biomarker is flow-mediated dilation of the brachial artery. Treatment of vascular inflammation is expected to prevent or to reduce symptoms of depression. Several tentative treatments for this form of depression can be envisioned: eicosapentaenoic acid (EPA), valproate, Vagus-nerve stimulation, nicotinic α7 agonists, and agonists of the cannabinoid CB₂-receptor.

Systemic inflammation is associated with depressive symptoms differentially by sex and race: a longitudinal study of urban adults

Systemic inflammation may influence trajectories of depressive symptoms over time, perhaps differentially by sex and race. Inflammatory markers and the Center for Epidemiologic Studies-Depression scale [total score: CES-D_total and four distinctive domains: somatic complaints, depressed affect, positive affect and interpersonal problems] were examined among African-American (AA) and White urban adults participating in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study [2004-2013, Age_base:30-64 y, mean ± SD follow-up time: 4.64 ± 0.93 y, N = 150 (with cytokine data) to N = 1,767 (with other inflammatory markers)]. Findings suggest that serum concentrations of high-sensitivity C-reactive protein (hsCRP), z-inflammation composite score [ICS, combining elevated hsCRP and ESR with low serum albumin and iron], and serum interleukin (IL) 1β were positively associated with ΔCES-D_total (Δ: annual rate of increase) among Whites only. IL-12 was directly related to ΔCES-D_total among men and AA. The race-specific associations of hsCRP, ICS, IL-1β and the sex-specific association of IL-12 with ΔCES-D_total were replicated for the "depressed affect" domain. Similarly, among men, lower serum albumin and higher ICS were linked with higher baseline "somatic complaints". IL-10 among AA and IL-12 among men were inversely related to Δ"positive affect", while "interpersonal problems" were cross-sectionally associated with IL-6 among AA and IL-10 among Whites. Finally, baseline ICS was positively associated with incident "elevated depressive symptoms" (EDS: CES-D_total ≥ 16) among AA (HR = 1.28, 95% CI: 1.04-1.56, P = 0.017). Overall, systemic inflammation was directly linked to increased depressive symptoms over time and at baseline, differentially across sex and race groups. More longitudinal research is needed to replicate our findings.

Novel Treatment Targets Based on Insights in the Etiology of Depression: Role of IL-6 Trans-Signaling and Stress-Induced Elevation of Glutamate and ATP

Inflammation and psychological stress are risk factors for major depression and suicide. Both increase central glutamate levels and activate the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system. Both factors also affect the function of the chloride transporters, Na-K-Cl-cotransporter-1 (NKCC1) and K-Cl-cotransporter-2 (KCC2), and provoke interleukin-6 (IL-6) trans-signaling. This leads to measurable increases in circulating corticosteroids, catecholamines, anxiety, somatic and psychological symptoms, and a decline in cognitive functions. Recognition of the sequence of pathological events allows the prediction of novel targets for therapeutic intervention. Amongst others, these include blockade of the big-K potassium channel, blockade of the P2X4 channel, TYK2-kinase inhibition, noradrenaline α2B-receptor antagonism, nicotinic α7-receptor stimulation, and the Sgp130Fc antibody. A better understanding of downstream processes evoked by inflammation and stress also allows suggestions for tentatively better biomarkers (e.g., SERPINA3N, MARCKS, or ¹³C-tryptophan metabolism).

Dietary inflammatory index and depression: a meta-analysis

OBJECTIVE

The purpose of the present meta-analysis was to evaluate the association between the inflammatory potential of diet, determined by the dietary inflammatory index (DII®) score, and depression.

DESIGN

Systematic review and meta-analysis.

SETTING

A comprehensive literature search was conducted in PubMed, Web of Science and EMBASE databases up to August 2018. All observational studies that examined the association of the DII score with depression/depressive symptoms were included.

SUBJECTS

Four prospective cohorts and two cross-sectional studies enrolling a total of 49 584 subjects.

RESULTS

Overall, individuals in the highest DII v. the lowest DII category had a 23 % higher risk of depression (risk ratio (RR)=1·23; 95 % CI 1·12, 1·35). When stratified by study design, the pooled RR was 1·25 (95 % CI 1·12, 1·40) for the prospective cohort studies and 1·16 (95 % CI 0·96, 1·41) for the cross-sectional studies. Gender-specific analysis showed that this association was observed in women (RR=1·25; 95 % CI 1·09, 1·42) but was not statistically significant in men (RR=1·15; 95 % CI 0·83, 1·59).

CONCLUSIONS

The meta-analysis suggests that pro-inflammatory diet estimated by a higher DII score is independently associated with an increased risk of depression, particularly in women. However, more well-designed studies are needed to evaluate whether an anti-inflammatory diet can reduce the risk of depression.

Coffee Consumption and the Risk of Depression in a Middle-Aged Cohort: The SUN Project

Coffee is one of the most widely consumed drinks around the world, while depression is considered the major contributor to the overall global burden of disease. However, the investigation on coffee consumption and depression is limited and results may be confounded by the overall dietary pattern. We assessed the relationship between coffee intake and the risk of depression, controlling for adherence to the Mediterranean diet. We studied 14,413 university graduates of the 'Seguimiento Universidad de Navarra' (SUN) cohort, initially free of depression. We evaluated coffee consumption using a validated food-frequency questionnaire (FFQ). Incident depression cases were adjudicated only if the participant met two criteria simultaneously: (a) validated physician-diagnosed depression together with (b) new onset of habitual antidepressant use. Both criteria were needed; participants meeting only one of them were not classified as cases. Participants who drank at least four cups of coffee per day showed a significantly lower risk of depression than participants who drank less than one cup of coffee per day (HR: 0.37 (95% CI 0.15⁻0.95)). However, overall, we did not observe an inverse linear dose⁻response association between coffee consumption and the incidence of depression (p for trend = 0.22).

Depression and peripheral inflammatory profile of patients with obesity

This narrative review will present and discuss clinical data from 16 cross-sectional and 6 longitudinal studies examining the relationship between body mass index (BMI), symptoms of depression and peripheral inflammation. Our aim is to determine which of obesity and depression contributes best to the peripheral low-grade inflammation frequently associated to both conditions. Studies including a complete evaluation of inflammatory markers are scarce and high levels of interleukin-6 (IL-6) and C-reactive protein (CRP) are the most consistent findings associated with obesity and symptoms of depression. Among the cross-sectional studies, seven studies, including a total of 9421 individuals, pointed to BMI as the major factor associated with systemic low-grade inflammation. However, in four studies, including 16,837 individuals, CRP levels remained associated with the symptoms of depression even after correction for BMI, suggestion that in the absence of overweight or obesity other sources of peripheral inflammation might contribute to presence of depressive symptoms. Additionally, another five studies, including 5569 individuals failed to find an association between depression and peripheral inflammation, reinforcing the heterogeneity of this condition. In the longitudinal data, changes in BMI were associated with a reduction in depressive scores at follow-up, after bariatric surgery or after diet. In four longitudinal studies, high levels of CRP were found to be associated with depression even after adjustment for BMI and weight loss, further corroborating the idea that other sources of peripheral inflammation might contribute to depressive symptoms. Thus it seems that both obesity and depressive symptoms can contribute to peripheral inflammation, and once installed the presence of inflammation can contribute to several behavioral alterations that reinforce the cyclic pattern of co-occurrence observed in patients with obesity and MDD. Future clinical studies should focus on strategic efforts to collect new data and to improve or standardize methods for the evaluation of depression, body composition and a more complete inflammatory profile. These approaches are essential for the development of pharmacological and/or non-pharmacological strategies designed to break this cyclic pattern of co-occurrence.

Dietary patterns, body mass index and inflammation: Pathways to depression and mental health problems in adolescents

BACKGROUND

Observational studies suggest that dietary patterns may impact mental health outcomes, although biologically plausible pathways are yet to be tested. We aimed to elucidate the longitudinal relationship between dietary patterns, adiposity, inflammation and mental health including depressive symptoms in a population-based cohort of adolescents.

METHODS

Data were provided from 843 adolescents participating in the Western Australian Pregnancy Cohort (Raine) Study at 14 and 17 years (y) of age. Structural equation modelling was applied to test our hypothesised models relating dietary patterns, energy intake and adiposity (body mass index) at 14 y to adiposity and the pro-inflammatory adipokine (leptin) and inflammation (high sensitivity C-reactive protein - hs-CRP) at 17 y, and these inflammatory markers to depressive symptoms (Beck Depression Inventory) and Internalising and Externalising Behavioral Problems (Child Behavior Check List Youth Self- Report) at 17 y. We further tested a reverse hypothesis model, with depression at 14 y as a predictor of dietary patterns at the same time-point.

RESULTS

The tested models provided a good fit to the data. A 'Western' dietary pattern (high intake of red meat, takeaway, refined foods, and confectionary) at 14 y was associated with higher energy intake and BMI at 14 y, and with BMI and biomarkers of inflammation at 17 y (all p < .05). A 'Healthy' dietary pattern (high in fruit, vegetables, fish, whole-grains) was inversely associated with BMI and inflammation at 17 y (p < .05). Higher BMI at 14 y was associated with higher BMI (p < .01), leptin (p < .05), hs-CRP (p < .05), depressive symptoms (p < .05) and mental health problems (p < .05), all at 17 y.

CONCLUSION

A 'Western' dietary pattern associates with an increased risk of mental health problems including depressive symptoms in adolescents, through biologically plausible pathways of adiposity and inflammation, whereas a 'Healthy' dietary pattern appears protective in these pathways. Longitudinal modelling into adulthood is indicated to confirm the complex associations of dietary patterns, adiposity, inflammation and mental health problems, including depressive symptoms.

Relationship between adherence to Dietary Approaches to Stop Hypertension (DASH) diet indices and incidence of depression during up to 8 years of follow-up

OBJECTIVE

Our aim was to evaluate the relationship between adherence to different Dietary Approaches to Stop Hypertension (DASH) diet indices and the risk of depression.

DESIGN

In a prospective study we assessed 14051 participants of a dynamic (permanently ongoing recruitment) prospective cohort (the Seguimiento Universidad de Navarra (SUN) Project), initially free of depression. At baseline, a validated FFQ was used to assess adherence to four previously proposed DASH indices (Dixon, Mellen, Fung and Günther). To define the outcome we applied two definitions of depression: a less conservative definition including only self-reported physician-diagnosed depression (410 incident cases) and a more conservative definition that required both clinical diagnosis of depression and use of antidepressants (113 incident cases). Cox regression and restricted cubic splines analyses were performed.

RESULTS

After a median follow-up period of 8 years, the multiple-adjusted model showed an inverse association with the Fung DASH score (hazard ratio (HR)=0·76; 95 % CI 0·61, 0·94) when we used the less conservative definition of depression, and also under the more conservative definition (HR=0·63; 95 % CI 0·41, 0·95). We observed a weak inverse association with the Mellen DASH score, but no statistically significant association was found for the other definitions. The restricted cubic splines analyses suggested that these associations were non-linear (U-shaped).

CONCLUSIONS

Moderate adherence to the DASH diet as operationalized by Fung and Mellen was related to lower depression risk. Since these associations were non-linear, additional prospective studies are required before the results can be generalized and clinical recommendations can be given.

Saturated high-fat feeding independent of obesity alters hypothalamus-pituitary-adrenal axis function but not anxiety-like behaviour

Overconsumption of dietary fat can elicit impairments in emotional processes and the response to stress. While excess dietary lipids have been shown to alter hypothalamus-pituitary-adrenal (HPA) axis function and promote anxiety-like behaviour, it is not known if such changes rely on elevated body weight and if these effects are specific to the type of dietary fat. The objective of this study was to investigate the effect of a saturated and a monounsaturated high-fat diet (HFD) on HPA axis function and anxiety-like behaviour in rats. Biochemical, metabolic and behavioural responses were evaluated following eight weeks on one of three diets: (1) a monounsaturated HFD (50%kcal olive oil), (2) a saturated HFD (50%kcal palm oil), or (3) a control low-fat diet. Weight gain was similar across the three diets while visceral fat mass was elevated by the two HFDs. The saturated HFD had specific actions to increase peak plasma levels of corticosterone and tumour-necrosis-factor-alpha and suppress mRNA expression of glucocorticoid and mineralocorticoid receptors, corticotropin-releasing hormone and 11β-hydroxysteroid dehydrogenase-1 in the paraventricular nucleus of the hypothalamus. Both HFDs enhanced the corticosterone-suppressing response to dexamethasone administration without affecting the physiological response to a restraint stress and failed to increase anxiety-like behaviour as measured in the elevated-plus maze and open field tests. These findings demonstrate that prolonged intake of saturated fat, without added weight gain, increases CORT and modulates central HPA feedback processes. That saturated HFD failed to affect anxiety-like behaviour can suggest that the anxiogenic effects of prolonged high-fat feeding may rely on more pronounced metabolic dysfunction.

Obesity

Excessive fat deposition in obesity has a multifactorial aetiology, but is widely considered the result of disequilibrium between energy intake and expenditure. Despite specific public health policies and individual treatment efforts to combat the obesity epidemic, >2 billion people worldwide are overweight or obese. The central nervous system circuitry, fuel turnover and metabolism as well as adipose tissue homeostasis are important to comprehend excessive weight gain and associated comorbidities. Obesity has a profound impact on quality of life, even in seemingly healthy individuals. Diet, physical activity or exercise and lifestyle changes are the cornerstones of obesity treatment, but medical treatment and bariatric surgery are becoming important. Family history, food environment, cultural preferences, adverse reactions to food, perinatal nutrition, previous or current diseases and physical activity patterns are relevant aspects for the health care professional to consider when treating the individual with obesity. Clinicians and other health care professionals are often ill-equipped to address the important environmental and socioeconomic drivers of the current obesity epidemic. Finally, understanding the epigenetic and genetic factors as well as metabolic pathways that take advantage of 'omics' technologies could play a very relevant part in combating obesity within a precision approach.

Relationship between body weight and the increment in serum brain-derived neurotrophic factor after oral glucose challenge in men with obesity and metabolic syndrome: A prospective study

Brain-derived neurotrophic factor (BDNF) plays a role in energy homeostasis. However, the postprandial BDNF change has not been well investigated. We hypothesized that the BDNF increment after oral glucose challenge is associated with body weight.To address this possibility, man adults with obesity in conjunction with metabolic syndrome were compared with normal weight controls at baseline in the initial cross-sectional protocol. The obese subjects then underwent a 12-week program for body-weight reduction in the prospective protocol. The area under the curve (AUC) of serum BDNF was recorded during a 75 g oral glucose tolerant test and the BDNF AUC index was defined as [(AUC of BDNF) - (fasting BDNF2 hours)]/(fasting BDNF2 hours).A total of 25 controls and 36 obese subjects completed the study assessments. In the cross-sectional protocol, the BDNF AUC index was significantly higher in the obese subjects than in the controls (9.0 ± 16.5% vs. - 8.0 ± 22.5%, P = 0.001). After weight reduction (from 97.0 ± 12.5 kg to 88.6 ± 12.9 kg, P < 0.001), the percentage change of body weight was significantly associated with the BDNF AUC index after the study (95% CI between 0.21 and 1.82, P = 0.015). Using 6% weight reduction as a cut-off value, a larger weight reduction was able to reliably predict a negative BDNF AUC index.In conclusion, a high BDNF AUC index was observed for obese men in this study, whereas the index value significantly decreased after body-weight reduction. These findings suggest that postprandial BDNF increment may be associated with obesity.

Intake of High-Fat Yogurt, but Not of Low-Fat Yogurt or Prebiotics, Is Related to Lower Risk of Depression in Women of the SUN Cohort Study

BACKGROUND

Yogurt and prebiotic consumption has been linked to better health. However, to our knowledge, no longitudinal study has assessed the association of yogurt and prebiotic consumption with depression risk.

OBJECTIVE

We longitudinally evaluated the association of yogurt and prebiotic consumption with depression risk in a Mediterranean cohort.

METHODS

The SUN (Seguimiento Universidad de Navarra) Project is a dynamic, prospective cohort of Spanish university graduates. A total of 14,539 men and women (mean age: 37 y) initially free of depression were assessed during a median follow-up period of 9.3 y. Validated food-frequency questionnaires at baseline and after a 10-y follow-up were used to assess prebiotic (fructans and galacto-oligosaccharide) intake and yogurt consumption (<0.5, ≥0.5 to <3, ≥3 to <7, and ≥7 servings/wk). Participants were classified as incident cases of depression when they reported a new clinical diagnosis of depression by a physician (previously validated). Multivariable Cox proportional hazards models were used to calculate HRs and 95% CIs.

RESULTS

We identified 727 incident cases of depression during follow-up. Whole-fat yogurt intake was associated with reduced depression risk: HR for the highest [≥7 servings/wk (1 serving = 125 g)] compared with the lowest (<0.5 servings/wk) consumption: 0.78 (95% CI: 0.63, 0.98; P-trend = 0.020). When stratified by sex, this association was significant only in women (HR: 0.66; 95% CI: 0.50, 0.87; P-trend = 0.004). Low-fat yogurt consumption was associated with a higher incidence of depression (HR: 1.32; 95% CI: 1.06, 1.65; P-trend = 0.001), although this association lost significance after the exclusion of early incident cases, suggesting possible reverse causation bias. Prebiotic consumption was not significantly associated with depression risk.

CONCLUSIONS

Our study suggests that high consumption of whole-fat yogurt was related to a lower risk of depression in women of the SUN cohort. No association was observed for prebiotics. Further studies are needed to clarify why the yogurt-depression association may differ by fat content of the yogurt.

Brain-gut-microbiota axis: challenges for translation in psychiatry

PURPOSE

The accruing data linking the gut microbiome to the development and function of the central nervous system has been proposed as a paradigm shift in neuroscience. The gut microbiota can communicate with the brain via neuroimmune, neuroendocrine, and neural pathways comprising the brain-gut-microbiota axis. Dysfunctional neuroimmune pathways are implicated in stress-related psychiatric disorders.

METHODS

Using depression as our primary example, we review both the preclinical and clinical evidence supporting the possible role played by the gut microbiota in stress-related psychiatric disorders. We consider how this can inform future treatment strategies and outline the challenges and necessary studies for moving the field forward.

RESULTS

The role played by the gut microbiota has not been fully elucidated in psychiatric populations. Although tempting to speculate that psychiatric patients may benefit from therapeutic modulation of the brain-gut-microbiota axis, the translational applications of the results obtained in rodent studies have yet to be demonstrated.

CONCLUSIONS

Evidence of altered gut microbiota composition and function in psychiatric patients is limited and cannot be regarded as proven. Moreover the efficacy of targeting the gut microbiota has not yet been established, and needs further investigation.

LINE-1 methylation levels, a biomarker of weight loss in obese subjects, are influenced by dietary antioxidant capacity

OBJECTIVES

Epigenetic markers, and in particular DNA methylation, have come to the fore as new tools in the personalization of the treatment of obesity and its comorbidities. The objectives of the current investigation were to identify epigenetic biomarkers that might be predictive of response to a weight-loss intervention, and to better understand the influence of certain nutrients (particularly antioxidants) on the epigenome.

METHODS

Global DNA (LINE-1) methylation levels were assessed in peripheral blood mononuclear cells (PBMCs) from 96 obese volunteers of the Metabolic Syndrome Reduction in Navarra study, using a methylation-sensitive high resolution melting approach after bisulfite modification.

RESULTS

Baseline LINE-1 DNA methylation levels were significantly higher (5.41%) in high responders (>8% of weight loss) as compared to low responders (<8%) to the energy-restricted treatment. Indeed, a LINE-1 methylation higher than 84.15% may be predictive of a high response to the hypocaloric diet. Statistically significant correlations were found between LINE-1 baseline DNA methylation levels and the response to the treatment involving total fat mass and body weight. Furthermore, LINE-1 baseline methylation levels positively correlated with baseline dietary total antioxidant capacity (TAC).

DISCUSSION

LINE-1 methylation levels in PBMCs might be used to predict response to a dietary weight-loss intervention, and seem to be related to the dietary TAC.

TRIAL REGISTRATION

www.clinicaltrials.gov : NCT01087086.

DNA hypermethylation of the serotonin receptor type-2A gene is associated with a worse response to a weight loss intervention in subjects with metabolic syndrome

Understanding the regulation of gene activities depending on DNA methylation has been the subject of much recent study. However, although polymorphisms of the HTR2A gene have been associated with both obesity and psychiatric disorders, the role of HTR2A gene methylation in these illnesses remains uncertain. The aim of this study was to evaluate the association of HTR2A gene promoter methylation levels in white blood cells (WBC) with obesity traits and depressive symptoms in individuals with metabolic syndrome (MetS) enrolled in a behavioural weight loss programme. Analyses were based on 41 volunteers (mean age 49 ± 1 year) recruited within the RESMENA study. Depressive symptoms (as determined using the Beck Depression Inventory), anthropometric and biochemical measurements were analysed at the beginning and after six months of weight loss treatment. At baseline, DNA from WBC was isolated and cytosine methylation in the HTR2A gene promoter was quantified by a microarray approach. In the whole-study sample, a positive association of HTR2A gene methylation with waist circumference and insulin levels was detected at baseline. Obesity measures significantly improved after six months of dietary treatment, where a lower mean HTR2A gene methylation at baseline was associated with major reductions in body weight, BMI and fat mass after the treatment. Moreover, mean HTR2A gene methylation at baseline significantly predicted the decrease in depressive symptoms after the weight loss treatment. In conclusion, this study provides newer evidence that hypermethylation of the HTR2A gene in WBC at baseline is significantly associated with a worse response to a weight-loss intervention and with a lower decrease in depressive symptoms after the dietary treatment in subjects with MetS.