Diet, Depression, and Anxiety

Dietary interventions for perinatal depression and anxiety: a systematic review and meta-analysis of randomized controlled trials

Despite growing evidence on the impact of diet on mental health and symptoms of depression, the scope of dietary impact on depression remains poorly understood. In this systematic review by Selvaraj et al. (2022), the authors examined evidence from both systematic and observational studies (up to January 2021) looking at the links between depression and diet in older people, adults, and adolescents. Analysis of the studies that met inclusion criteria (three systematic reviews, one meta-analysis, three cross-sectional studies, and two cohorts) demonstrated that older adults have an increased likelihood of suffering from malnutrition and depression while adopting a healthy diet early in life can help enhance favorable long term mental health outcomes. Observational evidence points to the role of eating a healthy diet (rich in vegetables and fruits) and decreasing the consumption of pro-inflammatory dietary components (fast food, junk food, elevated meat consumption) in decreasing the incidence of clinical depression or suffering from symptoms of depression. Based on these findings, the authors recommend conducting further studies (particularly randomized controlled and prospective cohorts) to improve the understanding of the mechanisms governing the links between depression and diet. [NPID: Diet, feeding habits, feeding behavior, mood disorders, low mood, depression, dietary pattern, dietary habits]

Most current research approaches investigating the relationship between depression and nutrition focuses on the impact of specific nutrients and/or dietary patterns (such as the Mediterranean or vegan diets). In this study by Owczarek et al. (2022), the authors conducted the first study investigating the influence of nutritional deficiencies on depression in adults using data from the National Health and Nutrition Examination Survey (NHANES). Data analysis identified four nutrient deficiency classes, including deficiencies in dietary fiber and magnesium, and a population of ‘nutrient deprived’ adults were recognized. Further analysis demonstrated a significant degree of depression in nutrient-deprived individuals, with female gender and suffering from arthritis being the most substantial predictors of suffering from severe depression, while income and age were robust protective factors against depression, as meeting minimum caloric requirements conferred the highest protection against nutrient deprivation. The authors recognize that, despite the existing limitations in the study not taking into account the impact of dietary consumption above the minimum recommendations, their study demonstrates the influence of adequate nutrition on suffering from depression, and that further work to identify depression risk factors will provide further proof to the concept of nutrient deficiency profiling [NPID: Depression, diet, nutrient deficiency, psychonutrition]

The Healthy Beverage Index (HBI) is a validated tool that helps us understand the impacts of overall beverage consumption, and is utilized in many studies that investigate the links between HBI and positive alterations in health status. Nevertheless, the evidence on the links between beverage consumption patterns and the mental health status of individuals remains insufficient. Thus, Rasaei et al. (2022) conducted their cross-sectional study to investigate the links between HBI and psychological disorders in a sample of 199 overweight and obese women (aged between 18-55 years). The participants submitted a semi-quantitative food-frequency questionnaire (FFQ) to evaluate their intake of beverages, and the total depression anxiety stress (DASS-21) questionnaire to provide data on their psychological status. The results demonstrated a modest substantial relationship between HBI and DASS score, where participants with high HBI were less likely to suffer from depression, compared to those with low HBI. Thus, the authors conclude that associations exist between total DASS score and HBI, and that the higher the HBI, the lower the chances of suffering from depression. The authors further comment that more adequately designed research studies are necessary to confirm these results. [NPID: Depression, anxiety, stress, mental health, healthy beverage index, obesity]

Research investigating the effects of single nutrients on depression have failed to produce reliable results, and come short in inspecting the intricate intercommunication between nutrients. Thus, a recently growing body of literature now aims at exploring the relationship between overall diet intake and depression. To that end, Lai JS et al. (2014) conducted a systematic review and meta-analyses of studies investigating the relationship between diet patterns and depression in community-dwelling adults. The authors searched through six electronic databases for articles of thorough methodology that were published up to August 2013. Out of the results of 13 observational studies that were analyzed, the authors identified two main dietary patterns: a “healthy” pattern, with a high intake of fruits, vegetables, fish, and whole grains, and a “Western pattern,” composed of refined grains, processed meat foods or snacks, and high-sugar and high-fat products. Findings showed that the healthy diet pattern was linked to significantly lower chances of developing depression. On the other hand, while there was no significant findings that linked Western diet and depression, the authors note that the studies were insufficient to deduce the nature of this link accurately. The authors conclude that more high-quality randomized controlled and cohort trials are necessary to verify these findings, specifically, studies that can investigate the temporal course of the relationship linking diet patterns and depression in community-dwelling adults. [NPID: depression, western, healthy, dietary pattern, community-dwelling].

This 2022 review analyzed a collection of research articles that used dietary interventions as a treatment for depression among adult populations. No funding was provided for this review. Firstly, there was a systematic search conducted on several databases to find studies treating adults with depression using either whole food or whole diet interventions. The studies were then assessed for quality using the Academy of Nutrition and Dietetics Quality Criteria Checklist. Seven studies met the eligibility criteria, composed of 49,156 participants in total. All seven of these studies reported improvement of depressive outcomes following dietary intervention. The effect size, which calculates the strength of the relationship between the dietary intervention and depressive outcome, varied from small to very large. The data generated and reviewed was limited by the inconsistency in some of these research papers. Nevertheless, the overall findings indicate that eating fresh produce, wholegrains, low-fat dairy, and foods with lean protein is beneficial in depression. In addition, positive results were observed for reducing the intake of processed and high-fat foods. [NPID: diet, depression, dietary interventions, review, nutrition, wholegrains, dairy, fats, processed foods]

Upon identifying a lack of literature investigating the association between major dietary formats and the mental health of patients who suffer from migraines, Arab, Rafie, and Hadi et al. (2022) conducted their study to investigate the potential links between empirically-derived diet formats and mental health disorders, including depression, anxiety, and stress. Their sample, which included 262 Iranian migraine patients between the ages of 20 to 50 years old, was acquired through simple random sampling. The patients had their previous year’s dietary intake evaluated using a validated 168-item, semi-quantitative Food Frequency Questionnaire (FFQ), which identified three major dietary patterns through principal component analysis (PCA). These patterns included a “traditional” diet (composed of solid oils, sweets, caffeine, legumes, and refined grains), a “western” diet (involving a high intake of fast foods, snacks, processed meat, fish, cola drink, condiments, dairy, and vegetable pickles), and a “healthy” dietary pattern (characterized by a high intake of fruits, vegetables, egg, whole grains, nuts and seeds, meat, and poultry). Participants’ mental health was assessed using the Depression, Anxiety, and Stress Scales (DASS-21) Questionnaire. The authors found that the participants in the highest tertile of the healthy dietary pattern were less likely to suffer from depression and stress. However, no significant links were found connecting the western or the traditional dietary patterns and mental illness. To help decrease the odds of experiencing depression or stress, the authors conclude that migraine patients would benefit from increasing their intake of fruits, eggs, vegetables, nuts and seeds, whole grains, meat, and poultry, and by decreasing their intake of fast foods and snacks, fish, processed meat, condiments, cola drink, dairy, and pickles. [NPID: Dietary pattern, factor analysis, migraine, depression, anxiety, stress]

Despite anxiety being the most prevalent of mental disorders, the majority of evidence on the role of nutrition in the onset and course of mental disorders fails to take anxiety into account. Aucion M. et al (2021) conducted this scoping review to identify existing literature on anxiety disorders and nutrition to help elucidate associations between diet and anxiety symptoms or prevalence. Te researchers also aimed to identify gaps and opportunities for future research. Following established approaches for conducting scoping reviews and using an online program (Abstrackr) to screen for abstracts and titles, a total of 55,914 unique results were identified. Of which, the included 1,541 studies demonstrated a link between decreased odds of anxiety and increased dietary intake of fruits, vegetables, omega-3 fatty acids, “healthy” dietary patterns (with a higher intake of vegetables, fruit, whole grains, fish, legumes, and unprocessed meat), caloric restriction, ketogenic diet, broad-spectrum micronutrient supplements, zinc, magnesium, selenium, probiotics, and a range of phytochemicals (caffeine, green tea, culinary herbs, turmeric, saffron, soy, nut/seed extract, flavonoids, carotenoids). Furthermore, consuming a fatty diet, inadequate tryptophan and dietary protein intake, high intake of sugar and refined carbohydrates, and “unhealthy” dietary patterns (higher intake of processed foods, sugar and sweetened foods, soft drinks, fried foods, processed meats, “junk food,” and “fast food”) were found to increase the odds of suffering from anxiety. Recognizing the limitation of this review, with a majority of the studies included being animal and observational studies and only 10% of intervention studies including participants with anxiety disorders, the authors call for conducting more quality studies on populations of patients suffering from anxiety disorders. [NPID: nutrition, diet, food, anxiety, mental health, psychiatry, nutritional science, dietetics]

Major depressive disorder (MDD) is implicated in the majority of disabling health outcomes across the globe. Some works reported on the links between depression and dietary habits, however, the results remained inconclusive. In this case-control study by Khosravi et al. (2015), the authors examine the relationship between diet and depression in a sample of 330 depressed patients and 660 healthy controls. The participants were matched with respect to age, sex, and community, and had their annual food intake retrospectively assessed using a validated semi-quantitative food frequency questionnaire. Through data analysis, two major dietary patterns were successfully identified: a healthy pattern (defined as a diet rich in “fruits, cruciferous, yellow, green leafy and other vegetables, low-fat dairy, whole grains, nuts, and olives”) and unhealthy dietary pattern (defined as a diet rich in “refined grains and breads, high-fat dairy, solid oils, liquid oils and mayonnaise, pickle, snacks, soft drinks, industrial fruits and juice, red meats, poultry, processed meats, and sweets”). After taking several variables into account, such as non-depression drug use, employment, marital status, family size, and body mass index, it was discovered that consuming a healthy diet was substantially associated with a lower prevalence of depression while consuming an unhealthy diet was associated with a higher prevalence for depression. In summary, the authors demonstrate that healthy and unhealthy dietary patterns are linked to depression risk and that these results may be utilized in fashioning interventions that promote healthy dietary strategies to prevent depression. [NPID: Major depressive disorder, epidemiology, nutrition, dietary pattern, depression]

Upon identifying a lack of literature investigating the association between major dietary patterns and mental health in migraine patients, Arab, Rafie and Hadi et al. (2022) conducted their study to explore the relationship between empirically-derived dietary patterns and mental health disorders, namely depression, anxiety and stress, in a sample of Iranian migraine patients. Selecting a total of 262 migraine patients between the ages of 20-50 years through simple random sampling and determining dietary intake during the previous year using a validated 168-item, semi-quantitative food frequency questionnaire (FFQ), three major dietary patterns were identified using principal component analysis (PCA). These patterns included a “traditional” diet (composed of solid oils, sweets, caffeine, legumes, and refined grains), a “western” diet (rich in fast foods and snacks, processed meat, fish, cola drink, condiments, dairy, and vegetable pickles), and a “healthy” dietary pattern (characterized by high intake of fruits, vegetables, egg, whole grains, nuts and seeds, meat, and poultry). Participants’ mental health was evaluated using the Depression, Anxiety and Stress Scales (DASS-21) questionnaire. The authors found that participants in the highest tertile of the healthy dietary pattern had lower odds for depression and stress. However, no significant association was observed between the western and the traditional dietary patterns and mental disorders. Current findings urge migraine patients to increase their intake of fruits, vegetables, eggs, whole grains, nuts and seeds, meat, and poultry and reduce the intake of fast foods and snacks, processed meat, fish, cola drink, condiments, dairy, and vegetable pickles to diminish the chance of depression and stress. [NPID: Dietary pattern, factor analysis, migraine, depression, anxiety, stress]

Studies of single nutrients on depression have produced inconsistent results, and do not consider the complex interactions between nutrients that exist within foods and dietary patterns. Therefore, a growing body of literature aims at investigating the relationship between overall dietary patterns and depression. To that end, Lai JS et al. (2014) conducted a systematic review and meta-analyses of studies investigating the association between dietary patterns and depression in community-dwelling adults. Lai et al. searched through six electronic databases, selecting methodologically rigorous articles that were published up to August 2013 which investigated the association between diet patterns and depression in adults. Study selection, quality rating and data extraction were completed by two independent reviewers. Effect sizes of eligible studies were pooled using random-effects models, and findings that could not be meta-analyzed had their summaries presented. A total of 21 studies were identified, and results from 13 observational studies were pooled. The results found two main dietary patterns - a “healthy” pattern, with a high intake of fruits, vegetables, fish, and whole grains, and a “Western pattern”, composed of refined grains, processed meat foods or snacks, and high-sugar and high-fat products. Findings showed that the healthy diet pattern was significantly associated with reduced odds for depression. On the other hand, while there was no significant association found between the Western diet and depression, the authors note that the studies were too few to provide a precise estimate of this effect. Lai et al. conclude that more high-quality randomized controlled and cohort trials are needed to confirm these findings, specifically those that would explore the temporal sequence of this association between dietary patterns and depression in community-dwelling adults. [NPID: depression, western, healthy, dietary pattern, community-dwelling].

This 2022 review analyzed a collection of research articles that used dietary interventions as a treatment for depression among adult populations. No funding was provided for this review. Firstly there was a systematic search conducted on several databases to find studies treating adults with depression using either whole food or whole diet interventions. The studies were then assessed for quality using the Academy of Nutrition and Dietetics Quality Criteria Checklist. Seven studies met the eligibility criteria, composed of 49,156 participants in total. All seven of these studies reported improvement of depressive outcomes following dietary intervention. The effect size, which calculates the strength of the relationship between the dietary intervention and depressive outcome, varied from small to very large. The data generated and reviewed was limited by the inconsistency in some of these research papers. Nevertheless, the overall findings indicate that eating fresh produce, wholegrains, low-fat dairy, and foods with lean protein is beneficial in depression. In addition, positive results were observed for reducing the intake of processed and high-fat foods. [NPID: diet, depression, dietary interventions, review, nutrition, wholegrains, dairy, fats, processed foods]

This 2021 study assessed the relationship between wholegrain consumption and depressive symptoms since wholegrains contain fibers, minerals, and vitamins that are thought to positively influence depressive symptoms. The study was conducted on a sample of 24,776 adults (age range 18 to 91) living in Tianjin, China. Around 19% of the male participants showed signs of depression, while the prevalence rate was slightly higher among the females (~22%). Compared to people who never ate wholegrains, participants who consumed wholegrains less than once a week were 23% less likely to have depression. The odds ratio of depression decreased as whole grain consumption frequency increased (0.73 odds ratio for those who ate once a week and 0.68 for those who ate two times or more per week). These results suggest that higher consumption of wholegrains can potentially prevent or improve depressive symptoms. Prospective or intervention studies are needed to confirm these findings. [NPID: wholegrains, depressive, depression, China, Chinese, diet, nutrition, fibers, minerals, vitamins]

In this 2021 study, over ten thousand Korean adults were surveyed on their diet and eating habits. The aim was to analyze the link between nutrient intake and eating habits with depression, according to gender and age. The data indicated several significant correlations between depression and levels of cholesterol, dietary fiber, and sodium. In addition, depression was found to be strongly associated with frequency of breakfast, lunch, dinner, and eating out. There were also many relationships according to age and gender. For example, depression was related to sugar intake, and frequency of breakfast, lunch, and eating out among young women. While depression related to sodium and lunch frequency among middle-aged men, links with dietary fibers, breakfast, and eating out frequency were found among middle-aged women. More associations were discovered between depression with energy, moisture, carbohydrate, lunch, and dinner frequency (in late middle-aged men), with breakfast and lunch frequency (among late middle-aged women), vitamin A, carotene, lunch, and eating out frequency (among older age men), and fat, saturated fatty acids, omega-3 fatty acid, omega-6 fatty acid, and eating out frequency (among the older age women). These statistics can be used to form dietary strategies for depression prevention that consider factors such as gender and age. [NPID: Korea, Korean, adults, eating habits, dietary habits, diet, nutrition, nutrients, depression, depressive, age, older, elderly, women, men, young, breakfast, lunch, dinner, eating out, middle-aged, middle age]