Diet, Depression, and Anxiety

Childhood and adolescence are crucial times for the development of mental health. Many favorable health outcomes, such as a decreased risk of mental health problems and fewer psychiatric symptoms, have been associated with the Mediterranean diet (MD). This study by Camprodon-Boadas et al. (2024) aimed to look into the relationships between children's and adolescents' mental health outcomes and their Mediterranean diet (MD) adherence. A comprehensive analysis of primary studies examining the relationship between adherence to the MD and mental health symptoms or problems was carried out. The authors searched the following databases for relevant literature from the time of conception up to November 2022: PubMed, Scopus, Web of Science, MEDES, Dialnet, and Latindex, evaluated using the Newcastle-Ottawa Scale. Thirteen of the 450 studies—six cross-sectional, four case-control, two randomized clinical trials, and one longitudinal cohort study—met the inclusion criteria (n = 3058 children and adolescents, age range = 8.6 - 16.2 years). Of these, there was a substantial protective correlation reported in five publications (71.42%) analyzing attention-deficit/hyperactivity disorder, four publications (80%) analyzing depression, and two publications (50%) analyzing anxiety. Furthermore, six of the articles (46.15%) were deemed to be of moderate level, while seven articles (53.84%) were classified as excellent quality. The results indicate that children's and teenagers' mental health may be shielded by following the MD. Promoting adherence to the MD may, therefore, contribute to preventing the onset of clinical psychiatric symptoms, reducing their severity, and improving the prognosis among young individuals. [NPID: Mediterranean diet, adolescent, child, mental health, psychiatry]

In this study by Dahlsgaard, Lewis & Spergel (2023), the authors evaluated the Food Allergy Bravery (FAB) concept, a new, concise, cognitive-behavioral-based intervention that targets anxiety in children who suffer from an anxiety-related food allergy (FAA). Children diagnosed with FAA (8-12 years of age) were recruited along with their parents, receiving a course of FAB (6 treatment sessions) in a group setting. Participants were evaluated for quality of life (Food Allergy Quality of Life Questionnaire-Parent Form) and severity of anxiety (Child Anxiety-Related Emotional Disorders and Food Allergy Anxiety scales) at several time points: before FAB, after FAB, and at two and four months. Analysis of the results revealed a substantial improvement in quality of life and reductions in anxiety severity in both children and parents. Participants reported high levels of satisfaction and clinical improvement with FAB, completing the full course and attending a minimum of 5 sessions, and maintained these results during follow-up evaluations. The authors conclude that FAB can be an acceptable, feasible intervention modality to address FAA, however, further randomized controlled trials are necessary to gain more evidence. [NPID: Anxiety, children, cognition, feasibility studies, food hypersensitivity, quality of life, food allergy bravery]

Dietary inflammatory index (DII) and dietary antioxidant index (DAI) are novel tools that measure the biological impact of a consumed diet. Dietary consumption is known to impact our mental health status. In this cross-sectional study by Dehghan et al. (2022), the authors investigated the links between DII, DAI, and mental health in a sample of 364 female adolescents who attended school. Participants submitted a 3-day food record, which was used to calculate DII and DAI, while the Depression Anxiety Stress Scales-21 was used to evaluate their anxiety, depression, and stress. Preliminary analysis revealed that 19.4% of participants were overweight (body mass index [BMI] for age > +1 z-score) and that participants suffered from mental health derangements (anxiety 26.6%, stress 25.7%, and depression 21.4%). Data analysis revealed that high DII scores were substantially associated with mental health derangements compared to scores in the first tertile, an association that lost its statistical significance when confounders were adjusted (BMI, energy intake, age, family income, parental education level). On the other hand, lower DAI scores were substantially linked to a decrease in depression and anxiety. The authors conclude that anti-inflammatory diets enhance the mental health status of adolescent females, and can present a potential intervention to treat psychosocial derangements. [NPID: Adolescent girls, Dietary Antioxidant Index, Dietary Inflammatory Index, mental health]

Driven by a lack of evidence regarding the links between depression and anxiety in children and adolescents and the consumption of sugar-sweetened beverages (SSB), Liu et al. (2022) conducted their cross-sectional study on a sample of 1311 children and adolescents (girls n = 653, ages between 7-17) to explore any potential associations, especially concerning body stratification. Social anxiety scale for children (SASC) and Children's Depression Inventory (CDI) were utilized to evaluate symptoms of depression and anxiety in children, while SSB intake was noted through questionnaires, and body composition using dual-energy X-ray (DEXA) bone densitometry. Initial data analysis revealed that 63.77% of participants consumed SSB at an average of 0.35 servings/day, while 29.75% suffered from social anxiety and 13.96% suffered from depression. Adjusting for confounders (sex, age, maternal smoking status, parental education status, BMI, income, single-child household, intake of fried foods, intake of fruits, physical activity, and screen time) revealed that participants who drank ≥1 serving/day suffered more depressive and anxious symptoms, however, that association was not statistically substantial. Furthermore, the authors discovered that children and adolescents with a higher body fat content or lower lean body mass had a higher likelihood of suffering from symptoms of depression when drinking ≥1 serving/day of SSB. The authors conclude that their findings demonstrate the impact of SSB intake on suffering from anxiety and/or depression in children and adolescents and that these observations were especially prominent in individuals with higher fat percentages or lower fat-free mass. [NPID: Sugar sweetened beverages, anxiety, depression, children, adolescents, dietary intake]

Adolescents suffer several vulnerabilities throughout this transitionary period of their lives, including mental health challenges. In this cross-sectional study by Gratão et al. (2022), the authors investigated the links between dietary habits, eating breakfast, having meals with family members, and the prevalence of common mental health derangements in adolescents. Data on a population of 71,553 Brazilian adolescents (12-17 years of age) was extrapolated from the Study of Cardiovascular Risk in Adolescents, revealing that participating adolescents followed one of two distinct dietary patterns: a healthy pattern (inclusive of a higher consumption of vegetables, cereals, meats and legumes) and an unhealthy pattern (with higher intake of sweetened beverages, chips, candies, stuffed sweet cookies, and a lower intake of fresh fruits). Adolescents in the second or third quartiles of the healthy dietary pattern were found to exhibit a lower incidence of common mental health disorders, an effect that was also seen with increasing the frequency of having breakfast or enjoying meals with family members. Thus, the authors conclude that adopting a healthy dietary pattern is linked to improved mental health outcomes in adolescents, which should be the subject of health promotion efforts. [NPID: Mental health, adolescence, public health, food habits, eating behaviors]

The detriment to mental health is becoming more pervasive globally, further complicated by an increasing scarcity in mental healthcare access and delivery. This scarcity encouraged looking into alternative preventative options, such as the use of nutrition to enhance mental health, which is gaining more attention in low- and middle-income countries that suffer from a particular pervasiveness of undernutrition. DiGirolamo et al. (2022) investigated if a protein-energy nutritional supplement, administered within the first 1,000 days of life, could reduce the chances of suffering from mental distress during adulthood, compared to a low energy-no protein supplement or to administering supplements outside of the first 1000 days of life. Data on 1,249 participants was extrapolated from a longitudinal cohort protein-energy supplementation trial (1969-1977, ages 0-7 years and follow-up at ages 40-57 on 2017-2018). Adult participants submitted the WHO Self-Reporting Questionnaire 20 (SRQ-20) to evaluate their mental distress, accounting for early-life conditions, current life stress, and other life variables such as education. The results revealed that administering supplements during the first 1,000 days of life was responsible for up to a 63% reduction in the likelihood of suffering from mental distress in adulthood. The authors conclude that populations suffering from undernutrition can benefit from administering a protein-energy supplement during the first 1000 days of life, in terms of a reduction in the odds of suffering from mental distress during adulthood. [NPID: Adult mental distress, early childhood nutrition, longitudinal cohort, low- and middle- income, prevention, protein-energy supplementation]

This 2021 study examined the relationship between lifestyle habits and depressive symptoms among a sample of Norwegian adolescents who partook in the Ungdata Surveys in 2017-2019. The survey asked the adolescents (aged 13-19 years) about their depressive behaviors and lifestyle habits (such as physical activity level, social media use, gaming, dietary habits, smoking, smokeless tobacco, and alcohol intoxication). Kleppang et al. found that depressive signs were significantly less likely to be reported by those who took part in some form of physical activity at least 3 times per week, used social media 3 hours or less on a daily basis, played video games 3 hours or less per day, non-smokers, and who hadn’t been intoxicated (alcohol) in the past 12 months. Among the girls, low depressive symptoms showed correlations with high consumption of healthy foods and low intake of unhealthy food and drinks. A similar relationship was observed among the boys. There was also a strong association between higher adherence to healthy lifestyle habits with lower risk of having depressive symptoms among both males and females, with 60% and 48% reduced odds in boys and girls, respectively. This study highlights that a healthier lifestyle is linked with lower chances of having depression. [NPID: lifestyle, depression, anxiety, lifestyle choices, lifestyle habits, Norway, Norwegian, depression, alcohol, smoking, video games, healthy lifestyle, healthy foods]

Fisk, J., Khalid, S., Reynolds, S. A., & Williams, C. M. (2020). Effect of 4 weeks daily wild blueberry supplementation on symptoms of depression in adolescents. The British journal of nutrition, 1–8. Advance online publication. https://doi.org/10.1017/S0007114520000926 Since adolescence represents a vulnerable period for developing depression, Fisk et al. (2020) are exploring the potentially positive effect of consuming foods with high flavonoid content on risk for depressive disorders. A wild blueberry intervention had previously shown its ability to increase positive affect in children and young adults. This present trial investigated the impact of eating wild blueberries daily for 4 weeks on short-term and chronic mood in adolescents. Sixty-four young and healthy subjects (12-17 years old) were randomized to either receive the wild blueberry supplement or a matched placebo. When compared with the placebo group, significantly fewer depressive symptoms were reported after the intervention period by the participants who ate wild blueberries. However, there was no marked difference between these two groups in terms of anxiety symptoms or short-term affect. Further analysis is warranted in order to determine the mechanisms involved in this potential link between flavonoid intake and mood. Wild blueberry supplementation could represent a novel strategy for preventing adolescent depression and improving public mental health. [NPID: intervention, blueberries, fruits, depression, depressive symptoms, flavonoids, children, anxiety, young adults, mood, adolescents, chronic mood, placebo, controlled trial, RCT]

The aim of this 2021 systematic review was to examine the relationship between fruit and vegetable consumption and depressive symptoms among young people and adults aged 15-45. Although the association between fruit and vegetable intake with mental health has already been identified, there have been limited studies involving young people and adults. A total of 12 studies (found in the systematic search) met the criteria of analyzing fruit and vegetable intake (separately and/or together), with depression or depressive symptoms as the outcomes. One of the studies was of “very good” quality, while nine studies were “good”, and two studies were deemed to be of “moderate” quality based on the measure (Newcastle-Ottawa Scale). Although most of the cohort studies supported the link between fruit consumption and lower risk of developing depression, inconsistencies were identified when analyzing the impact of vegetable intake independently and when the combined effect of fruit and vegetable consumption was evaluated. Nevertheless, the evidence seems to point to the validity of this association. Hopefully this data can be utilized to address the mental illness burden in young people and adults (aged 15-45 years). [NPID: depression, anxiety, depressive symptoms, fruits, vegetables, fruits and vegetables, systematic review, review, young people, adults]

This 2019 study investigated the relationship between dietary patterns and mental health in Chinese adolescents, by administering the Multi-dimensional Sub-health Questionnaire of Adolescents (MSQA) to assess emotional, conduct and social adaptation problems, and by collecting data on eating pattern using the semi-quantitative food frequency questionnaire (SQFFQ). Among 32 Chinese schools across 4 provinces, a total of 14,500 adolescents (in grade 7-12) completed eligible questionnaires. Four main patterns were identified: healthy, meat, sugar-sweetened beverages (SSBs) and fast foods patterns. The healthy pattern was associated with lower risk of psychological symptoms [adjusted odds ratio (aOR) = 0.59, 0.6, 0.62, 0.53, all p<0.01), while the the fast foods pattern (aOR = 2.16, 2.04, 1.84, 2.24, respectively, all p < 0.01), the SSBs pattern (aOR = 1.38, 1.34, 1.25, 1.56, respectively, all p < 0.01) and the meats pattern (aOR = 1.24, 1.15, 1.12, 1.28, respectively, all p < 0.05) were significantly related with increased incidence of psychological symptoms. Dose-response relationships were observed for all dietary patterns with psychological symptoms, except for meat eating patterns. The limitation of this study was that SQFFQ made it difficult to determine the accurate consumption of foods, while Xu et al. (2019) even admitted that they could not infer causality because of the cross-sectional design. Nevertheless, this study emphasized the importance of eating patterns during adolescence in the context of mental health. [NPID: depression, anxiety, mental health, China, healthy, meat, sugar-sweetened beverages, fast food, adolescence]

The aim of this 2020 study was to investigate the association between the variables, nutrition, physical activity (PA), lifestyle behaviors (isolated and combined) with symptoms of insomnia, depression and anxiety among adolescents. A survey was conducted in May 2020 on 1,756 middle school students. Students with low family income, living rurally, with excessive fear, who are female, have a sibling, and those who have been left behind were more likely to have a poorer lifestyle or be in a worse mental state. After controlling for confounding factors, more respondents with both poor nutrition and inactive PA appeared to report insomnia (OR=2.16) and depressive (OR=2.57) symptoms than those with only one behavior or neither of them, indicating the correlation between both poor nutrition and inactive PA with higher prevalence of insomnia, depression and anxiety symptoms. It is therefore crucial that adolescents pursue a healthy lifestyle. [NPID: depression, anxiety, mental health, physical activity, insomnia, fear, rural, rural area, low income, female, siblings, women]

The aim of this 2018 study was to uncover the prevalence of depression and unhealthy food consumption among first-year college students, and to evaluate whether there is a link between their depression score and unhealthy food intake frequency. The 1,104 college freshmen (40.3% men; 59.7% women) studying at a public university in Mexico City, were examined on their food consumption (food frequency questionnaire) and depressive symptoms [the 20-item depression scale (CES-D)]. Depressive signs were identified in 18.2% of the men and 27.5% of the women, while the reporting of poor dietary habits were fairly common. Only 39.7% of the student sample practiced vigorous physical activity, and 30.3%, 49%, and 51.8% of participants reported eating fried foods, sweetened drinks, and sugary foods 2-7 times per week, respectively. Logistic regression analysis revealed that women were at more risk of developing depressive symptoms if they did not exercise regularly (< 75 min/week; OR = 1.80, p = 0.017), and frequently consumed fast food (OR= 2.08, p = 0.018), fried food (OR = 1.92, p = 0.01) and sugary food (OR = 2.16, p = 0.001). Lazarevich et al. (2018) could not find an association between food consumption and depression scores among male students, but there was a correlation between depression and low exercise frequency (OR = 2.22, p = 0.006). The researchers suggest that those women vulnerable to depression may use food as a coping mechanism to deal with negative mood. Institutional health promotion and nutritional education programs are encouraged to consider emotion and stress management. [NPID: depression, anxiety, Mexico City, fried food, sweetened drinks, sugar, coping mechanism, negative mood, stress, stress management, emotion]

The hypothesis of this robust U.S. study was whether fruit and vegetable (FV) consumption during adolescence could be linked to an attenuation in risk of developing depression in adulthood. The 3696 participants of this cohort study were taken from the Add Health Study, and were aged 17 at baseline in 1994-1995, and then were 29 at follow-up taking place between 2007-2008. Depression was measured using Center for Epidemiologic Studies Depression Scale (CES-D), while a questionnaire was completed detailing which fruit and vegetable items were consumed the day before, to determine fruit and vegetable intake. The group with the highest percentage failure to consume fruits and vegetables the day before was those who were classed as depressed at baseline and at follow-up also on the CES-D (31% for fruit, 42% for vegetables). But the association between FV consumption and depression was weakened after repeating in fully adjusted models. Although there was promise of an existing link, further studies are required and the use of different dietary measures could produce more robust evidence. [NPID: depression, anxiety, fruit, vegetables]

This study looks at the relationship between fruit and vegetable consumption and mental health in a British population and especially accounting for ethnicity, parenting and socioeconomic situations. 4683 adolescents aged 11-13 were extracted from the British multi-ethnic Determinants of Adolescents (now young Adult) Social well-being and Health (DASH) longitudinal study, and followed up after 3 years. Mental health was assessed through the Strengths and Difficulties Questionnaire as mean Total Difficulty Score (TDS) and participants were classed as probable cases of mental disorders if scores reached 17 (higher indicating increased psychological distress). After questioning the study group on the number of fruits and vegetables (FV) consumed daily, around 60-70% answered <5 portions, 20-30% with <1 servings per day. Data revealed the majority of ethnic minority groups were consuming less FV than their white peers. The value <1 portions of FV a day was still significantly correlated with average TDS in the fully adjusted models, while no effects from ethnicity and gender were detected. Low parental care partially reduced the association between FV and mental health, which could inspire research on parenting interventions and its possible developmental effect on children. [NPID: depression, anxiety, worry, fruit, vegetables, FV intake, Britain, socioeconomic status, psychological distress, children]

This longitudinally study analyses bi-directional associations between healthy lifestyles and mood disorders. Young adults (aged 26-31) were assessed at baseline and at the 5 year mark, for diagnosis of depression or dysthymia (persistent depression) and questioned on their lifestyle – (i.e., body mass index (BMI), smoker status, alcohol intake, recreational physical activity and healthy diet). The covariates included age, sex, socio-economic position, parental and marital status, social support, major life events, cardiovascular disease history, and self-rated physical and mental health. Independently of these factors, the risk of experiencing first episodes of mood disorders dropped 22% in those with higher lifestyle scores at baseline. An existing mood disorder at baseline was associated with lower incidence of improvement and greater chance of worsening in lifestyle choices. Healthy lifestyles may be mainly talked about in the promotion of preventing cardiovascular disease but this study implies they are closely related to mood disorders and mental health. [NPID: depression, anxiety, mood, dysthymia, smoking, alcohol, cardiovascular disease]

Mrug et. al (2019) explore the potential role of sodium and potassium excretion in depression by collecting overnight urine samples from adolescents growing up in low-income urbanised neighbourhoods. Samples were taken at the start of the study from 84 adolescents, half of whom were male, and 95% African-American. Depressive symptoms were self-reported at baseline and at the 1.5 year stage, and comparisons were drawn after adjusting for age, BMI, pubertal development and baselines depressive symptoms. The results showed severe depressive symptoms could be predicted by high sodium and low potassium levels in urine and highlighted no variation in trend between male and female. This implies diets made up of high sodium and low potassium content can predispose adolescents who live in poorer, urban areas to develop symptoms of depression. [NPID: depression, anxiety, mental illness, sodium, potassium, low income, African American]

In this cross-sectional study, the tie between eating patterns and mental health problems (gauged by the use of the Strengths and Difficulties Questionnaire) was investigated in a young Norwegian population (12-13 years old). Parents reported dietary intake through a modified Food Frequency Questionnaire (FFQ) which was then analysed to determine eating patterns (through principal component analysis). The results showed increased signs of psychiatric and hyperactivity-inattention disorders in adolescents on a less ‘varied Norwegian’ eating pattern, and in those with eating habits high in the ‘junk/convenient’ category, than the children who scored lower in scale. A higher score on a ‘snacking’ eating pattern was also correlated to higher risk of conduct/oppositional disorders than lower scores. The study concluded a strong correlation between diversified nutrient-rich diets and enhanced mental health, and the association between poor dieting and irregularly eating habits with poor mental health outcomes at the adolescent stage, independent of physical activity, sedentary activity and background variability. [NPID: depression, anxiety, mental illness, Norwegian, young adult, adolescence, hyperactivity-inattention disorders, ADHD, snacking, nutrient-rich, sedentary]

Mikolajczyk and his team (2009) conducts a cross-sectional multinational survey on first-year university students in Germany, Poland and Bulgaria to draw comparisons between nutritional intake, stress and depressive symptoms, and to explore any variations between the results of each country. The tests conducted on the students include the Cohen’s Perceived Stress Scale (to assess stress levels), a 12-item food frequency questionnaire (looking at diet quality), and a modified Beck Depression Index (to rate depression levels). The results demonstrated a variation in all 3 factorial tests between the countries and gender. None of the male student groups were linked to perceived stress or depression risk, whereas, higher perceived stress reported could be related to more frequent intake of sweets and fast food. A decrease in fruit and vegetable consumption was also associated with depressive symptoms in the female students. [NPID: depression, anxiety, mental illness, Germany, Poland, Bulgaria, stress, depressive symptoms, diet quality, fruit, vegetables, FV intake]

This robust systematic review scoured through around 1000 research articles from 5 decades to find out for us the relevance of good quality diets and eating habits with positive psychological health at all ages including adolescence. After analysing 56 relevant studies, Khanna et. al (2019) finds considerable differences in mental well-being depending on diet (consuming fruits and vegetables, fish, olive oil, nuts, and certain dairy products can positively affect depressive symptoms), whereas the western dietary patterns and behaviours have been linked with increased risk of depression. This current study proposes greater consideration of dietary requirements in the prevention and treatment of mental disorders. [NPID: depression, anxiety, mental illness, well-being, diet quality, children, adolescence, psychological health, Western-style diet, WS diet]

While observational studies are demonstrating an association between healthy dietary intake and mental health, this study aimed to elucidate some of the biological mechanisms underpinning this association. Specifically, the study examined the relationship between dietary patterns, BMI (Body Mass Index), and mental health. The study’s author and her colleagues (2018) collected data from 843 adolescents at age 14 and 17 respectively, along with BMI (body mass index) and biomarkers of inflammation (the hormone leptin and C-reactive protein). Findings indicated that a high intake of Western foods, including meat, takeaway foods, refined foods, and sugary foods, at the age of 14 was associated with a higher BMI. And that this higher BMI, by the age of 17, was associated with not only higher BMI, but higher biological markers of inflammation, depressive symptoms and mental health problems. This study provided increased understanding of some of the biological pathways occurring from the Western dietary pattern that connect this pattern with depression and mental health issues in adolescents. [NPID: depression, anxiety, mental illness, inflammation, leptin, C-reactive protein, meat, refined foods, sugary foods, sugar, Western-style diet, WS diet]

Głąbska et. al (2020) provides us with a systematic review of observational studies focusing on the association between fruit and vegetable intake and mental health in pre-schoolers and school-aged children. A total of 12 studies were picked out from the Pubmed and Web of Science databases, all of which were in English and dated up to June 2019. These studies included fruit and/or vegetables and products like juices, and various aspects of mental health such as general well-being, behavioural difficulties and problems, depressive symptoms, emotions, stress, or even depressive symptoms combined with anxiety. The researchers found that in most of the relevant studies, enhanced fruit and vegetable intake had a positive effect on mental aspects of health in pre-schoolers and school-aged children, although the reviewer urges more research on the area in a new sample group, and also points out many studies ended up recommending a generally more healthy dietary pattern rather than increasing fruit and vegetable consumption alone. [NPID: depression, anxiety, mental illness, FV intake, fruit, vegetables, children, well-being, behavioral difficulties, dietary pattern]

This study represents the only randomized controlled trial on young adults to date demonstrating that a diet intervention can reduce clinical symptoms of depression. Research is increasingly showing an association between poor diet and depression, while a healthy diet containing fruit, vegetables, fish, whole grains and lean meats and fish are showing an association with positive mental health. This study by Francis et al (2019) enrolled 101 young adults who had both symptoms of depression, and who consumed a poor diet, into two groups: a diet group (placed under a healthy diet intervention) and control group who continued with their habitually poor diet (Editor’s note: complete data for thirty-eight of the 101 individuals was analyzed). Measures were taken at baseline (before intervention) and after the intervention to determine each group’s symptoms of depression, mood, self-efficacy, and memory. The diet group reported lower depressive symptoms after the intervention compared to the control group. In this study, diet intervention reduced depression scores among young adults. [NPID: depression, anxiety, mental health, fruit, vegetables, FV intake, fish, lean meats, whole grains, mood, self-efficacy, memory]