Diet Quality Impacts Mental Health Aspects of University Students

Review Article

Austin J Nutri Food Sci. 2021; 9(2): 1158.

Diet Quality Impacts Mental Health Aspects of University Students

Mantzorou M¹*, Serdari A², Kostopoulos M¹ and Giaginis C¹*

1Department of Food Science and Nutrition, School of nvironment, University of Aegean, Myrina, Lemnos, Greece

2Department of Psychiatry and Child Psychiatry, Democritus University of Thrace, University Hospital of Alexandroupolis, Thrace, Greece

*Corresponding author: Maria Mantzorou, Department of Food Science and Nutrition, University of the Aegean, Mitropoliti Ioakim 2, Myrina, Lemnos, 81440, Greece

Constantinos Giaginis, Associate Professor of Human Physiology, Department of Food Science and Nutrition, University of the Aege-an, Mitropoliti Ioakim 2, Myrina, Lemnos, 81440, Greece

Received: September 13, 2021; Accepted: October 11, 2021; Published: October 18, 2021

Abstract

Introduction: Mental health problems, especially depression and anxiety, among university students are widespread, and begin pre-matriculation. Diet is among the factors contributing to mental health in all age groups.

Aim: The present review aims to critically summarize the observational studies and clinical trials that have investigated the association between mental health and diet quality in university student populations.

Methods: PubMed was comprehensively searched to identify studies that explore the role of aspects of diet quality on quality of life, depression, and anxiety in university students.

Results: Healthy dietary patterns, such as the Mediterranean and the DASH diet, diets with high intakes of antioxidants and antioxidant vitamins, folate, Zinc and Calcium are associated with less depressive symptoms. Higher alcohol and salt intake have also been associated with depression.

Conclusion: Healthy dietary patterns, with adequate micronutrient and antioxidant intakes are associated with better mental health status. However, further randomised controlled clinical studies are needed in order to clarify the cause and the effect of the observed associations.

Keywords: Diet; Anxiety; Depression; University students; Dietary patterns

Introduction

Mental health problems among undergraduate and postgraduate university students are widespread [1]. University students present with a significant number of mental health problems and high rates of psychological distress [2], which can affect college attrition and academic achievement [3,4], as well as students’ emotional and behavioural skills and social life [2].

Two recent studies, part of the WHO Mental Health Surveys [3,4] investigated the mental health status of university students. An earlier paper examined the associations between mental health disorders and college entry and attrition by comparing college students and non-students in the same age range (18-22 years old) in 21 countries, around the world, with low, middle and high incomes. One in five college students had mental health disorders the past year, but just 16.4% of those students received treatment [3]. Another one investigated the mental health problems among freshmen in an e-survey of students in Belgium. One in three new students reported mental health problems in the past year [4]. Notably, the WHO Survey [3] and the systematic review by Storrie et al. [2] found that the vast ma-jority of the students with mental health disorders were diagnosed before college entry (83.1% and 51%, respectively), highlighting the importance of mental health during adolescence.

Several studies have focused on medical students, and have shown that medical students have high levels of various mental health disorders, from depression to sleep disorders and burnout [5], which impair personal and occupational functioning. About one fourth of medical students had a mental health condition before attending medical school, and one in three consulted a mental health professional. Anxiety and stress were quite common [6], while the fear of stigmatization was also evident in this group of students [7].

The association between mental health and diet is being investigated [8-10]. Diet can affect mental health aspects of university students, as well. University students have turned away from healthy dietary patterns [11], while diet quality is important for adolescent mental health, and most university students have been diagnosed with mental health problems pre-matriculation. Taking into account the above, the present review aims to critically summarise the observational studies and clinical trials that have investigated the association between mental health and diet quality in university student populations.

In this aspect, PubMed database was comprehensively searched, using relevant keywords in order to identify observational studies and clinical trials that have investigated the role of diet quality on quality of life, depression and anxiety in university students. The keywords used were combinations of the following: depression, anxiety, stress, diet, probiotics, mental health, quality of life, university students, Mediterranean diet. We also hand-searched the reference list of the studies, as well as the reference list of relevant reviews.

Diet and Mental Health in the General Population

Substantial evidence points towards an association between nutrients [12], healthy dietary patterns and better mental health [8-10]. The effect of diet on mental health may also be mediated by gut microbiota [13], while other biological mechanisms [14] have also been proposed, including inflammation, oxidative stress, neuroplasticity and epigenetic modifications [15,16]. Concerning DNA methylation, nutrients such as folate, vitamins B6 and B12, choline and betaine [17] have the potential to impact DNA methylation. Nutritional deficiencies in utero and during infancy can influence brain development and possibly negatively impact behaviour [18-20]. In addition to this, diet has been implicated to mediate the relationship between inflammation, depression [21] and brain function [22], while low anti-oxidant capacity [23] and low antioxidant levels have been observed in patients with depression [24].

In adults, a longitudinal study showed that low diet quality was associated with higher risk of depressive symptoms and the higher adherence of traditional diet was associated with a lower risk of depressive symptoms [25], while the SUN cohort showed that high fast-food and commercial baked foods intake [26], higher consumption of added sugars and lower quality carbohydrate rich foods consumption [27] were associated with higher depression risk. Conversely, higher fruit, vegetable and nut consumption has been positively associated with better mental health status [28,29]. Adherence to the Mediterranean Diet (MD) has been positively associated with better mental health status [30,31], while MD supplemented with nuts resulted in lower depression risk in the PREDIMED study [32]. In addition to this, in the elderly, higher adherence to the MD was independently associated with better cognitive status and less depressive symptoms [33]. Zinc, Magnesium and folate intakes have been negatively associated with depressive symptoms [12], and micronutrient supplementation has been shown to be effective, regarding improvements on psychiatric symptoms [34].

Systematic reviews [35-37] regarding the association between diet quality and mental health and depression in children and adolescents have found that those with worse mental health reported adherence to poorer dietary pat-terns, although confounding factors need to be controlled in future studies [37]. In children and adolescents around the world, adherence to a traditional [38] and a healthy diet [39] has been positively associated with better mental health measures. Studies in healthy populations and patients have observed an association between higher diet quality and higher quality of life [40-43]. MD adherence has also been associated with better quality of life both in adolescents [40] and adults [41], which could be attributed to the palatable, non-restrictive nature of this healthy diet and the high nutrient density, which could play a role on the prevention of mental health disorders, as discussed above. In addition to this, a healthy dietary pattern, such as the MD had a positive impact on physical health [42], thus patients who follow a healthy diet may observe improvements on their physical health, with positive impact on their quality of life.

Mental health scores

Studies use questionnaires in order to assess the mental health of the students. The most commonly used ones, according to the bibliography are the Center for Epidemiological Studies Depression Scale (CES-D scale) by L.S. Radloff [43], where a score of 16 points or more is considered depressed, and the Depression Anxiety Stress Scales (DASS 21) by S.H. Lovibond, & P.F. Lovibond [44]., which have cut-off points for anxiety, depression and stress. Additionally, the Beck Depression Inventory (BDI-II) [45].

Is used for the severity of depressive symptoms with scores of 0 to 13 indicating minimal depression, 14-19 mild depression, 20-28 moderate depression, and 29-63 indicating severe depression. The General Health Questionnaire (GHQ-12) [46] assesses Anxiety and Depression, Social Dysfunction, and Loss of Confidence. The GHQ- 12 cut-off point has not been firmly set, and the most commonly used one is 2/3. Other studies use Zung’s Self-Rating Anxiety Scale [47]. and Zung’s Self-Rating Depression Scale. [48]. Lastly, the Positive and Negative Affect Schedule (PANAS) [49] has also been used. Studies use different scales, hence comparisons between studies should be done with caution [50,51].

Dietary Factors and Mental Health in University Students

Diet quality, depression and anxiety

Nine studies from the past 12 years have explored the relationship between diet quality and mental health in university students. The studies are summarised in Table 1. Unhealthy eating habits have been significantly associated with higher prevalence of anxiety, stress [52,53] and depression [52,54,55] scores in university students, according to relevant tools.

Table 1: Studies concerning dietary patterns and mental health in university populations.





  

    
Dietary pattern

    
Participants 

    
Country

    
Findings

    
References 

    
Ref number

  

  

    
Self-evaluation of diet as healthy or unhealthy

    
838 allied health professions students

    
Jordan

    
Self-evaluation of diet as unhealthy →↑    depression and anxiety scores (DASS 21)

    
Almhdawi et al., 2018

    
[52]

  

  

    
Healthy Eating Index

    
1055 university students

    
Spain

    
Unhealthy eating →↑ depression, anxiety and stress    (DASS 21)

    
Ramon-Arbues et al., 2019 

    
[53]

  

  

    
Eating practices

    
959 students

    
Poland

    
Healthy eating practices →↓    depressive symptoms (BDI-II)

    
Oleszko et al., 2019

    
[54]

  

  

    
Mediterranean Diet

    
10,094 initially healthy students

    
Spain

    
↑ MD adherence →↓ risk    of depression

    
Sánchez-Villegas et al., 2009

    
[58]

  

  

    
Mediterranean Diet

    
515 university students

    
Spain

    
↓ MD adherence →↑ stress

    
Chacon-Cuberos et al., 2019 

    
[59]

  

  

    
DASH diet

    
240 university students

    
Iran

    
↑DASH diet adherence →↓    depression, anxiety, and stress scores (GHQ-12 & DASS-21 scales)

    
Faghih et al., 2020

    
[60]

  

  

    
Dietary Guideline Adherence Index/Self-evaluation    of diet

    
2810 university students

    
Egypt

    
    
      
  • Dietary    Guideline Adherence Index was not associated with stress
    • 
      
  • Subjective    evaluation of healthy eating negatively associated with stress
    • 
      
  • Stress    was related with ↓ stress-induced food intake
    • 
    

    
El Ansari et al., 2015

    
[56]

  

  

    
Vegetarian diet 

    
2991 German and 12,405 Chinese university    students

    
Germany and China

    
    
      
  • Better    mental health at baseline → non-vegetarian diet 
    • 
      
  • In    Chinese students a vegetarian diet was an independent significant predictor    of future mental health
    • 
    

    
Velten et al., 2018

    
[62]

  

  

    
Vegetarian/Vegan diets 

    
1608 German and 12,744 Chinese university    students

    
Germany and China

    
No association, except for negative impact in    Chinese students concerning anxiety & depression

    
Lavalle et al., 2019

    
[63]

  

  

    
Recommendations of the Spanish Society of    Community Nutrition

    
117 students of a Faculty of Sciences

    
Spain

    
    
      
  • Macronutrients are    associated with mood 
    • 
      
  • A healthy dietary    pattern, with a high complex carbohydrate, high fibre, high aspartate,    and a low cholesterol diet, may provide benefits improving    the processing of social and affective information 
    • 
    

    
Ugartemendia et al., 2020

    
[72]

  

  

    
DASS-21:    Depression; Anxiety and Stress Scale - 21; BDI-II: Beck Depression    Inventory-II; MD: Mediterranean Diet; GHQ-12: General Health Questionnaire;    DASH: Dietary Approaches to Stop Hypertension. 

  










Table 1: Studies concerning dietary patterns and mental health in university populations.

In 838 Applied Medical Sciences students in Jordan, a student population with high rates of mental health problems, Almdawi et al. [52] found that self-evaluation of diet as “unhealthy” was independently associated with higher depression and stress scores [52]. The important role of the self-evaluation of the diet quality on mental health, was also highlighted in the study by El Ansari et al. [56], in Egypt, where despite the fact that the Dietary Guideline Adherence Index was not associated with stress, when the subjective evaluation of healthy eating was taken into consideration it was negatively associated with stress, while stress was associated with lower stress-induced food intake [56].

Considering objective tools, “unhealthy eating”, according to the Healthy Eating Index (modified by Norte et al. [57]) has been significantly associated with depression, anxiety and stress scores, according to the Depression Anxiety Stress Scales (DASS 21) in Spanish university students [53]. Another recent cross-sectional study from Poland, using the Beck Depression Inventory (BDI-II), found that increasing rates of healthy eating practices was associated with less depressive symptoms [54].

Few studies have investigated the association between MD adherence and mental health in this population group [11]. A followup study of the SUN Project explored the relationship between MD adherence and incidence of clinical depression in 10,094 healthy at baseline Spanish university graduates [58]. 4.4 years later, 480 depression cases were diagnosed. Higher MD adherence was significantly associated with lower risk of depression. Inverse doseresponse relationships were found for foods that characterize MD, namely fruit and nuts intake, the monounsaturated-to-saturatedfatty- acids ratio, and legume intake and depression risk [58]. Concerning stress, students with low MD adherence had higher stress scores, regarding the communication of their ideas, in the univariate, but not the multivariate analysis [59]. The multivariate analysis highlighted the fact that BMI and female sex were associated with higher academic stress scores, indicating a possible link between worse dietary habits during stressful periods [59]. Another healthy dietary pattern is the Dietary Approaches to Stop Hypertension (DASH) diet. Greater adherence to the DASH diet has been associated with better mental health, with lower depression, anxiety, and stress scores (General Health Questionnaire/GHQ-12 and DASS-21 scales) in Iranian university students [60].

In summary, adherence to dietary patterns that are characterized as healthy patterns are associated with better mental health status scores.

Vegetarian and vegan diets and mental health

Two studies have investigated the role of vegan and vegetarian diets on mental health (Table 1). Vegan and vegetarian diets are on the rise [61], however, there is a lack of studies in student populations concerning their impact on mental health. A longitudinal study aimed to evaluate certain lifestyle choices as predictors of mental health in German and Chinese students. Vegetarian diets were associated with worse mental health status. Better mental health at baseline was predicted by a non-vegetarian diet among other factors, while in Chinese students a vegetarian diet was a significant predictor of future mental health, after adjusting for lifestyle choices, age, gender, and baseline mental health [62]. However, a recent study that also explored this association in multiple countries found no significant association between a vegetarian diet and mental health in US, Russian and German participants, but it was associated with anxiety and depression in Chinese students [63]. This effect could be attributed to socio-economic factors that influence both mental health and the choice or need to adhere to a vegetarian diet in China. Hence, it is still unclear whether a plant-based diet can impact mental health in university students. Socio-economic factors and the reason behind choosing a vegetarian or vegan diet is an important factor to explore, as they can be used to mask disordered eating and eating behaviours [64,65].

Food groups and mental health

The impact of foods on mental health has been explored in sixteen studies (Table 2). Some studies show gender differences, which could be attributed to biological differences and sex differences regarding the relationship with food [66], as well as the female to male ratio in some studies. El Ansari et al. [67] found that consuming less nutritious (‘un-healthy’) foods (sweets, cookies, snacks, fast food) was significantly positively associated with perceived stress in females, and depressive symptoms in both men and women. Consumption of nutritious (‘healthy’) foods (fruits and vegetables) was significantly negatively associated with perceived stress and depressive symptoms for both men and women [67]. As symptoms of anxiety and depression increase, energy intake decreases and sugar intake increases [68]. Especially male university students consume more saturated fats, and less fruits and vegetables, as depressive symptoms increase [68], while fish and seafood consumption has been negatively associated with depressive symptoms [67]. Concerning stress, higher perceived stress score was significantly associated with less frequent fruit and vegetable intake, especially in males. Yet, no significant association was observed between the sweets, cakes and snacks intake and stress [56]. However, data from three countries, concerning male students, showed that food groups were not associated with perceived stress or depressive symptoms [66]. In females, perceived stress has been associated with higher consumption of sweets/fast foods and lower consumption of fruits and vegetables [66]. In female future dietitians, higher intake of sweets was independently associated with worse mental health in a pilot and cross-sectional study in Japan [69]. Although the authors did not describe a mechanism behind the association, their knowledge regarding diet quality and health could impact their relationship with food.

Table 2: Food impact on mental health in university populations.





  

    
Food group

    
Participants 

    
Country

    
Findings

    
References 

    
Ref number

  

  

    
Fruits and Vegetables

    
225 undergraduate US students

    
United States of America

    
Less fruit and vegetable intake with greater    depressive symptoms in men

    
Keck et al., 2020

    
[68]

  

  

    
3,706 university students

    
United Kingdom

    
Negative association with perceived stress and    depressive symptoms for men and women

    
El Ansari et al., 2014

    
[67]

  

  

    
696 German 489 Poland and 654 Bulgarian    university students

    
Germany, Poland, Bulgaria

    
Negative association with perceived stress &    depressive symptoms in women

    
Mikolajczyk et al., 2009

    
[66]

  

  

    
1956 university students from Appalachia

    
United States of America

    
Negative association with depression in males

    
Wattick et al.,2018

    
[73]

  

  

    
2810 university students

    
Egypt

    
Negative association with perceived stress,    especially in males

    
El Ansari et al., 2015

    
[56]

  

  

    
171 healthy young adults aged 18–25

    
New Zealand

    
    
      
  • No    changes were found for depressive symptoms, anxiety, or mood after 14-day    intervention
    • 
      
  • Better    well-being measures
    • 
    

    
Conner et al. 2017

    
[76]

  

  

    
Fruits 

    
60 male university students

    
Iran

    
Negative association with depression

    
Prohan et al. 2014

    
[70]

  

  

    
2579 college students

    
China

    
Positive independent association with stress and    depression

    
Liu et al. 2007

    
[71]

  

  

    
Meat

    
696 German 489 Poland and 654 Bulgarian    university students

    
Germany, Poland, Bulgaria

    
Negative association with depressive symptoms in    women

    
Mikolajczyk et al., 2009

    
[66]

  

  

    
Dairy

    
1055 university students

    
Spain

    
Negative association with prevalence of    psychological and sleep disturbances

    
Ramon-Arbues et al., 2019 

    
[53]

  

  

    
Legumes/Nuts/Seeds

    
60 male university students

    
Iran

    
Negative association with depression

    
Prohan et al. 2014

    
[70]

  

  

    
Fish and seafood

    
3,706 university students

    
United Kingdom

    
Negative association with depressive symptoms in    men

    
El Ansari et al., 2014

    
[67]

  

  

    
Sweets/Snacks/Baked goods/ Fast food

    
3,706 university students

    
United Kingdom

    
Positive association with

      
    
        
  • stress    in females,
    • 
        
  • depressive    symptoms in both men and women
    • 
      

    
El Ansari et al., 2014

    
[67]

  

  

    
696 German 489 Poland and 654 Bulgarian    university students

    
Germany, Poland, Bulgaria

    
Positive association with perceived stress in    women

    
Mikolajczyk et al., 2009

    
[66]

  

  

    
2579 college students

    
China

    
Positive independent association with stress and    depression

    
Liu et al. 2007

    
[71]

  

  

    
Sweets 

    
62 female university students

    
Japan

    
Positive association with worse mental health

    
Mochimasu et al. 2016 

    
[69]

  

  

    
Added sugar

    
1956 university students from Appalachia

    
United States of America

    
Positive association with anxiety

    
Wattick et al.,2018

    
[73]

  

  

    
225 undergraduate US students

    
United States of America

    
Higher intakes with increasing anxiety scores

    
Keck et al., 2020

    
[68]

  

  

    
Alcohol 

    
2658 university students

    
Nigeria

    
Alcohol dependence, abuse and hazardous use    positive association with major depressive disorder

    
Adewuya et al. 2006

    
[77]

  

  

    
793 black students

    
South Africa

    
Positive association with depressive symptoms

    
Peltzer, 2003 

    
[78]

  

  

    
2991 German and 12,405 Chinese university    students

    
Germany, China

    
↑ mental health in German and ↓ mental    health in Chinese students

    
Velten et al. 2018

    
[62]

  

  

    
475 nursing students

    
Australia

    
Alcohol score was associated with lower health    related quality of life

    
Heidke et al. 2021

    
[79]

  










Table 2: Food impact on mental health in university populations.

Excessive intake of sweets and low intake of dairy has recently been associated with higher prevalence of psychological and sleep disturbances in a university student population, with high rates of low diet quality [53]. Additionally, depressive symptoms were associated with less frequent consumption of fruits/vegetables and meat [66], while Prohan et al. found that students with depression exhibited lower intakes of fruits, legumes, nuts and seeds, than students without mental health problems [70].

High frequency of consumption of fresh fruit was associated with low levels of perceived stress and depression, while high frequency of ready-to-eat food and snack food was related with higher levels of perceived stress, and high intake of ready-to-eat and fast foods was positively associated with perceived depression [71]. Food choices are related to socio-economic status.

Furthermore, a recent Spanish study [72] also observed the negative impact on mental health of diets that defer from the traditional Mediterranean Diet, and the association between mental health aspects and macronutrients. The authors concluded that a healthy diet, rich in complex carbohydrates, insoluble fibre, and aspartate, and low in cholesterol could be beneficial for mental health [72].

Food insecurity has been related to worse mental health status [73-75]. A study in Appalachia [73] investigated the role of diet quality and food insecurity in university students. Concerning depression, food insecurity was an independent factor in both males and females, while and fruit and vegetable intake was independent predictors for depression in males only. Concerning anxiety, food insecurity and added sugar intake were significant predictors of anxiety [73]. Regarding fruit and vegetable intake, Conner et al. [76] undertook a 14-day clinical trial aiming to increase fruit and vegetable intake of 171 young adults aged 18-25, who had low intakes of fruits and vegetables. Participants were randomly assigned into either: a) Their usual diet; b) Their usual diet plus text message reminders to increase their fruit and vegetable consumption and a voucher to purchase fruits and vegetables; or c) A fruit and vegetable intervention where participants were given two additional daily servings of fresh fruits and vegetables to consume on top of their usual diet. The participants, who were given fruits and vegetables to consume, had improved their mental well-being (vitality, flourishing and motivation). However, no changes were found for depressive symptoms, anxiety, or mood, possibly due to the fact that the study participants were mentally healthy and the fact that the study was short-termed. The authors state that the benefits were not due to vitamin C, carotenoids, or mental expectations. This study highlights that improvements in food quality can positively impact mental health, even in healthy populations.

Sex differences and socio-economic factors do play a role on both food choice and mental health. Consumption of more nutritious is associated with better mental health status and lower depression and anxiety scores.

Alcohol use has also been investigated in four studies in relation to mental health in university students. In Nigeria, compared with those who do not drink, students who present alcohol dependence, abuse and hazardous use were at higher risk for major depressive disorder (according to the Mini International Neuropsychiatric Interview). However, normal alcohol use was not associated with depression [77]. In black South-African students, alcohol drinking was associated with depressive symptoms (according to the 13-item short Beck Depression Inventory) [78], and in Australian nursing students alcohol score was associated with lower health related quality of life [79]. However, the effect of alcohol intake may be cultural. The frequency of alcohol consumption predicted better mental health in German and poorer mental health in Chinese students [62], while the levels of alcohol intake play a role on its impact on mental health.

Nutrients and antioxidants on mental health

Anti-Inflammatory diet patterns and mental health: Lately, the inflammatory and anti-inflammatory effects of dietary patterns interest health professionals, while oxidative stress and inflammation have been observed in individuals with depression [80]. Two studies have explored relative associations in university students (Table 3).

Table 3: Micronutrients and Antioxidants on mental health in university populations.





  

    
Micronutrients 

    
Participants 

    
Country

    
Findings

    
References 

    
Ref number

  

  

    
Antioxidants/Dietary Inflammatory Index

    
134 female university students

    
Turkey

    
Positive association between Dietary Inflammatory    Index score & depression

    
Açik et al., 2019

    
[81]

  

  

    
Antioxidants-

      lutein & zeaxanthin

    
60 male university students

    
Iran

    
Students with depression had:

      
    
        
  • ↓ quality diet and lower antioxidants intake 
    • 
        
  • ↓ Total Antioxidant Capacity 
    • 
      

    
Prohan et al. 2014

    
[70]

  

  

    
Calcium

    
56 female college students with depression and    122 female students without depression

    
Korea

    
Positive association with depression score (CES-D    scale)

    
Park et al., 2019

    
[83]

  

  

    
Zinc

    
308 female university students

    
Iran

    
    
      
  • ↓ Zinc levels & intake in students with depression 
    • 
      
  • Zinc    intakes and concentration were correlated with the Beck questionnaire scores
    • 
    

    
Amani et al., 2010

    
[82]

  

  

    
Folic Acid

    
56 female college students with depression and    122 female students without depression

    
Korea

    
Positive association with depression score (CES-D    scale)

    
Park et al., 2019

    
[83]

  

  

    
425 post graduate students

    
Iran

    
Intake was related to the total score of    Depression Scale CES-D & the subscales depressive affect and    interpersonal difficulties

    
Yary, 2013

    
[84]

  

  

    
Vitamins A and C

    
60 male university students

    
Iran

    
Students with depression had:

      
    
        
  • ↓ quality diet and lower antioxidants intake 
    • 
        
  • ↓ Total Antioxidant Capacity 
    • 
      

    
Prohan et al. 2014

    
[70]

  

  

    
56 female college students with depression and    122 female students without depression

    
Korea

    
Positive association with depression score (CES-D    scale)

    
Park et al., 2019

    
[82]

  

  

    
Salt

    
20222 university students from 26 countries

    
various

    
Positive association with depression score (CES-D    scale)

    
Peltzer et al., 2015

    
[86]

  

  

    
Omega 3 fatty acids 

    
68 medical students received either 2.5 g omega-3    /day (2085 mg eicosapentaenoic acid and 348 mg docosahexanoic acid) or    placebo

    
United States of America

    
↓ anxiety after intervention and    lower inflammation (reductions in stimulated IL-6 and tumour necrosis factor    alpha production)

    
Kiecolt-Glaser et al. 2011 

    
[87]

  

  

    
Tryptophan

    
25 healthy university students cross-over study

    
United States of America

    
    
      
  • ↑ tryptophan diet →↑ mood (PANAS scale) ↓    anxiety scores (Zung’s Self-Rating Anxiety Scale),
    • 
      
  • ↓ tryptophan diet → borderline depression scores    (Zung’s Self-Rating Depression Scale)
    • 
    

    
Lindseth et al.

    
[88]

  

  

    
CES-D:    Center for Epidemiological Studies-Depression; PANAS: Positive and Negative    Affect Schedule. 

  










Table 3: Micronutrients and Antioxidants on mental health in university populations.

The association between the Dietary Inflammatory Index and depression was explored by Açik et al. [81] in female university students. Students were found to follow a “pro-inflammatory” diet and a significant positive association between Dietary Inflammatory Index score and depressive symptoms was observed. A case-control study on 60 male university students, examined the association between diet and the Beck Depression Inventory-II, the dietary and serum total antioxidant capacity and high-sensitive C-reactive protein concentrations. Students with depressive symptoms had a lower quality diet, lower Total Antioxidant Capacity and lower antioxidant intake [70]. Hence, a dietary pattern that could be characterized as anti-inflammatory, such as the Mediterranean Diet, may play a role in depression.

Nutrients and antioxidants on mental health: Studies concerning specific nutrients have also been undertaken. Five studies explored micronutrient intake and one randomised controlled clinical trial was undertaken concerning omega-3 fatty acids, while another one examined the role of tryptophan on mental health (Table 3). Nutrient intake can impact mental health in university students, highlighting the role of a healthy diet that provides adequate intakes of all the essential nutrients.

In female university students, a series of studies explored the association between Zinc intake, Zinc status and depression. Zinc intake and serum Zinc concentrations were by two thirds lower in the students with depression than in healthy controls, while Zinc intake and concentration were correlated with the Beck Depression Inventory scores. Stu-dents with depression also had lower consumption levels of red meat and chicken, which are main food sources of Zinc [82].

Moreover, in Korean female college students, depression score (Center for Epidemiological Studies Depression Scale- CES-D scale) was positively associated with life stress and negatively associated with vitamin A, folic acid, vitamin C and calcium intakes, healthy diet and healthy dietary behaviours [83]. In post-graduate students in Iran, vita-min B9 intake was related with the total score of CES-D scale and the depressive affect and interpersonal difficulties of the two subscales of the CES-D (depressive affect and interpersonal difficulties) [84]. Moreover, Prohan et al. found that students with depression had lower intakes of the following antioxidants: vitamin C, beta-carotene, lutein, and zeaxanthin [70].

Considering carotenoids, Stringham et al. [85] undertook a randomised controlled trial regarding the mental health impact of macular carotenoids. 59 US participants were randomised to receive either placebo, 13mg, or 27mg per day macular carotenoids for 1 year, and were assessed at baseline, at 6 months and at the end of the trial. At baseline, Macular Pigment Optical Density (MPOD) was negatively associated with the Beck Anxiety Inventory score and the Brief Symptom Inventory score, while serum cortisol and psychological stress scores were also positively associated. Over the study period, improvements were observed on mental and physical health scores of both intervention groups versus the control group, indicating a positive impact of macular carotenoids in this healthy young adult population.

In undergraduate students with high depression rates, from 26 countries with high, medium and low-income countries [86] various factors were independently associated with depressive symptoms (assessed via the CES-D scale). Apart from socio-demographic factors, and traumatic events, unhealthy behaviours, such as smoking, irregular sleep, infrequent meals, and increased salt intake were independently associated with severe depressive symptoms [86].

The role of the omega-3 and omega-6 polyunsaturated fatty acids on depression and anxiety was investigated in a parallel group, placebo-controlled, double-blind 12-week randomised controlled clinical trial that compared omega-3 supplementation and placebo. 68 medical students provided serial blood samples during lower-stress periods, as well as on days before an exam. The students received either 2.5g omega-3/day, or placebo capsules in the proportions of the fatty acids in the typical American diet. Compared to control group, the intervention group had a 14% decrease in inflammation and a 20% reduction in anxiety scores, but not in depressive symptoms. Decreasing ratios of the plasma omega-6:omega-3 ratio led to lower anxiety scores and lower inflammation [87].

Lindseth et al. [88] examined the impact of dietary tryptophan on anxiety, mood and depression scores, in 25 healthy US university students, in a crossover study. A higher in tryptophan diet was associated with better mood (PANAS scale) and lower anxiety scores (Zung’s Self-Rating Anxiety Scale), while they had borderline depression scores after a low tryptophan diet (Zung’s Self-Rating Depression Scale) [88].

Probiotics and mental health

Two studies have been undertaken in university students, examining the role of probiotics on mental health. Nishida et al. [89] administered Lactobacillus gasseri CP2305 or placebo once daily for 24 weeks to 60 Japanese medical students before a stressful exam. The intake of the probiotic was successful in reducing anxiety and sleep disturbance (Spielberger State-Trait Anxiety Inventory and the Pittsburgh Sleep Quality Index) compared to placebo. Tran et al. [90] in their randomised, placebo-controlled trial with 86 healthy students found that probiotic administration for 28 days was successful on improving anxiety, especially in high distress students.

Conclusion

Mental health problems in university students begin before college enrolment, indicating the need for both timely prevention, early diagnosis, and accessible treatment. In accordance with other previous studies and reviews [91], our review findings point towards a positive association between healthy dietary patterns and university students’ mental health, as indicated by the results of randomised controlled trials. In general, a high-quality dietary pattern, like the Mediterranean Diet and the DASH diet, may positively affect mental health in university students. Surprisingly, our findings also pointed towards an association between vegan/vegetarian diets and worse mental health in a limited population (Chinese students), a finding that was also observed in the recent systematic review and meta-analysis of high quality studies by Igacuel et al. [92], especially for anxiety, in participants under 26 years of age in high quality studies. However, a recent meta-analysis did not find any significant associations between vegetarian diets and depression or anxiety with data from observational studies [93]. Another systematic review [94] found that high quality data support the fact that people who avoid meat are at higher risk of depression, anxiety, as well as self-harming Disturbed Eating habits that could be characterized as unhealthy have also been explored in relation to mental health, as they are com-mon in this age group. Disordered eating was common, while one-fifth of the students had moderate levels of depression and anxiety severity and almost half of the students engaged in at least one obsessivecompulsive disorder type behaviour [95]. Food avoidance, influenced by non-experts on nutrition, was also associated with depressive symptoms [96].

Higher fruit and vegetable intake, as well as high legume, nuts and seeds intake are related with better mental health status. Conversely, higher intakes of fast food, sweets and ready-made baked goods are related to a worse mental health status. Alcohol and salt intake also impact depression symptoms, although the impact of alcohol intake may differ among countries. Concerning micronutrients, zinc, vitamin A, vitamin B9, vitamin C, and calcium intakes are related to depression scores, while pro-inflammatory diets, with low antioxidant intakes are also associated with depression scores.

In children, greater dietary variety was associated with lower risk of internalizing disorder in subsequent years [97]. In women of all ages, a healthy dietary pattern has been associated with lower odds for major depression or dysthymia and for anxiety disorders. Conversely, a “western” type diet has been associated with a higher GHQ-12 score. Diet quality is independently and inversely correlated with GHQ-12 [8], while intake of magnesium, folate, and zinc have been associated with mental health [12]. On the other hand, omega-3 fatty acid supplementation may not be an effective preventing measure against depression and anxiety symptoms [98], despite the positive findings in university students [87].

Concerning gut flora, the gut-brain axis is regulated by microbes [99] and their impact on pathophysiology of mental disorders has been investigated in animal models and humans. There is evidence for altered microbiota in animal models of depression [100] and patients with depression [101,102]. Limited studies [103] so far have explored the effectiveness of probiotics [104] and prebiotics [105] on mental health, and two studies have been undertaken in university students, with positive results within one month.

It is important to note that the associations between diet and mental health are not well studied in university students, and randomised controlled clinical trials are still scarce. There are literature gaps concerning the impact of special diets on mental health problems in this population. Further studies, especially randomised trials are strongly recommended to clarify the causes behind the observed associations between diet, depression, and anxiety, and whether these associations may be due to reverse causality.

Declaration

Funding: This research is co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Programme «Human Resources Development, Education and Lifelong Learning 2014-2020» in the context of the project “Evaluation of the potential beneficial effect of the Mediterranean diet as a model of sustainable nutrition in mental health and welfare of the student population of Greek universities” (MIS 5047787).

Acknowledgements: This research is co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Programme «Human Resources Development, Education and Lifelong Learning 2014-2020» in the context of the project “Evaluation of the potential beneficial effect of Mediterranean Diet as a pattern of sustainable diet on the emotional health and the well-being status of student population of the Greek universities” (MIS 5047787).

References

  1. Eleftheriades R, C Fiala and MD Pasic. The challenges and mental health issues of academic trainees. F1000Research. 2020; 9: 104-104.
  2. Storrie K, K Ahern and A Tuckett. A systematic review: Students with mental health problems-A growing problem. International Journal of Nursing Practice. 2010; 16: 1-6.
  3. Auerbach RP, et al. Mental disorders among college students in the World Health Organization World Mental Health Surveys. Psychol Med. 2016. 46: 2955-2970.
  4. Bruffaerts R, et al. Mental health problems in college freshmen: Prevalence and academic functioning. J Affect Disord. 2018; 225: 97-103.
  5. Pacheco JP, et al. Mental health problems among medical students in Brazil: a systematic review and meta-analysis. Braz J Psychiatry. 2017; 39: 369- 378.
  6. Wilkes C, et al. Wellbeing and mental health amongst medical students in Canada. Int Rev Psychiatry. 2019; 31: 584-587.
  7. Hankir AK, A Northall and R Zaman. Stigma and mental health challenges in medical students. BMJ Case Rep. 2014: 2014.
  8. Jacka FN, et al. Association of Western and traditional diets with depression and anxiety in women. Am J Psychiatry. 2010; 167: 305-311.
  9. Lai JS, et al. A systematic review and meta-analysis of dietary patterns and depression in community-dwelling adults. The American Journal of Clinical Nutrition. 2013; 99: 181-197.
  10. Quirk SE, et al. The association between diet quality, dietary patterns and depression in adults: a systematic review. BMC psychiatry. 13: 175-175.
  11. Antonopoulou M, et al. Evaluating Mediterranean diet adherence in university student populations: Does this dietary pattern affect students’ academic performance and mental health? Int J Health Plann Manage. 2020; 35: 5-21.
  12. Jacka FN, et al. Nutrient intakes and the common mental disorders in women. J Affect Disord. 2012; 141: 79-85.
  13. Dawson SL, SR Dash and FN Jacka. The Importance of Diet and Gut Health to the Treatment and Prevention of Mental Disorders. Int Rev Neurobiol. 2016; 131: 325-346.
  14. Sominsky L and SJ Spencer. Eating behavior and stress: a pathway to obesity. Frontiers in psychology. 2014; 5: 434-434.
  15. Nestler EJ, et al. Epigenetic Basis of Mental Illness. The Neuroscientist: a review journal bringing neurobiology. neurology and psychiatry. 2016; 22: 447-463.
  16. Marx W, et al. Nutritional psychiatry: the present state of the evidence. Proc Nutr Soc. 2017; 76: 427-436.
  17. Stevens AJ, JJ Rucklidge and MA Kennedy. Epigenetics, nutrition and mental health. Is there a relationship? Nutr Neurosci. 2018; 21: 602-613.
  18. Wauben IP and PE Wainwright. The influence of neonatal nutrition on behavioral development: a critical appraisal. Nutr Rev. 1999; 57: 35-44.
  19. Liu J, et al. Malnutrition at age 3 years and externalizing behavior problems at ages 8, 11, and 17 years. Am J Psychiatry. 2004; 161: 2005-2013.
  20. Nyaradi A, et al. The role of nutrition in children’s neurocognitive development, from pregnancy through childhood. Front Hum Neurosci. 2013; 7: 97.
  21. Berk M, et al. So depression is an inflammatory disease, but where does the inflammation come from? BMC Medicine. 2013; 11: 200.
  22. Melo HM, LE Santos and ST Ferreira. Diet-Derived Fatty Acids, Brain Inflammation, and Mental Health. Front Neurosci. 2019; 13: 265.
  23. Moylan S, et al. Oxidative & nitrosative stress in depression: why so much stress? Neurosci Biobehav Rev. 2014; 45: 46-62.
  24. Liu T, et al. A Meta-Analysis of Oxidative Stress Markers in Depression. PLoS One. 2015; 10: e0138904.
  25. Le Port A, et al. Association between dietary patterns and depressive symptoms over time: a 10-year follow-up study of the GAZEL cohort. PloS one. 2012; 7: e51593-e51593.
  26. Sánchez-Villegas A, et al. Fast-food and commercial baked goods consumption and the risk of depression. Public Health Nutr. 2012; 15: 424- 432.
  27. Sanchez-Villegas A, et al. Added sugars and sugar-sweetened beverage consumption, dietary carbohydrate index and depression risk in the Seguimiento Universidad de Navarra (SUN) Project. Br J Nutr. 2018; 119: 211-221.
  28. Emerson SD and NS Carbert. An apple a day: Protective associations between nutrition and the mental health of immigrants in Canada. Social Psychiatry and Psychiatric Epidemiology. 2019; 54: 567-578.
  29. Fresán U, et al. Does the MIND diet decrease depression risk? A comparison with Mediterranean diet in the SUN cohort. 2019; 58: 1271-1282.
  30. Fresán U, et al. Does the MIND diet decrease depression risk? A comparison with Mediterranean diet in the SUN cohort. European Journal of Nutrition. 2019; 58: 1271-1282.
  31. Moreno-Agostino D, et al.
  32. Sánchez-Villegas A, et al. Mediterranean dietary pattern and depression: the PREDIMED randomized trial. BMC Medicine. 2013; 11: 208-208.
  33. Mantzorou M, et al. Mediterranean diet adherence is associated with better cognitive status and less depressive symptoms in a Greek elderly population. Aging Clinical and Experimental Research. 2020: 1-8.
  34. Rucklidge JJ and BJ Kaplan. Broad-spectrum micronutrient formulas for the treatment of psychiatric symptoms: a systematic review. Expert Rev Neurother. 2013; 13: 49-73.
  35. O’Neil A, et al. Relationship Between Diet and Mental Health in Children and Adolescents: A Systematic Review. American Journal of Public Health. 2014; 104: e31-e42.
  36. Khalid S, CM Williams and SA Reynolds. Is there an association between diet and depression in children and adolescents? A systematic review. Br J Nutr. 2016; 116: 2097-2108.
  37. Molendijk M, et al. Diet quality and depression risk: A systematic review and dose-response meta-analysis of prospective studies. J Affect Disord. 2018; 226: 346-354.
  38. Weng TT, et al. Is there any relationship between dietary patterns and depression and anxiety in Chinese adolescents? Public Health Nutr. 2012; 15: 673-682.
  39. Kulkarni AA, BA Swinburn and J Utter. Associations between diet quality and mental health in socially disadvantaged New Zealand adolescents. Eur J Clin Nutr. 2015; 69: 79-83.
  40. Knox E and JJ Muros. Association of lifestyle behaviours with self-esteem through health-related quality of life in Spanish adolescents. Eur J Pediatr. 2017; 176: 621-628.
  41. Galilea-Zabalza I, et al. Mediterranean diet and quality of life: Baseline cross-sectional analysis of the PREDIMED-PLUS trial. PLoS One. 2018; 13: e0198974.
  42. Carlos S, et al. Mediterranean Diet and Health Outcomes in the SUN Cohort. Nutrients. 2018: 10.
  43. Ye S, et al. Behavioral mechanisms, elevated depressive symptoms, and the risk for myocardial infarction or death in individuals with coronary heart disease: the REGARDS (Reason for Geographic and Racial Differences in Stroke) study. J Am Coll Cardiol. 2013; 61: 622-630.
  44. Lovibond SH and PF Lovibond. Manual for the depression anxiety stress scales. 1996: Psychology Foundation of Australia.
  45. Beck AT, et al. An inventory for measuring depression. Archives of general psychiatry. 1961; 4: 561-571.
  46. Schmitz N, et al. Diagnosing mental disorders in primary care: the General Health Questionnaire (GHQ) and the Symptom Check List (SCL-90-R) as screening instruments. Social Psychiatry and Psychiatric Epidemiology. 1999; 34: 360-366.
  47. Zung WW. A rating instrument for anxiety disorders. Psychosomatics: Journal of Consultation and Liaison Psychiatry. 1971.
  48. Zung WW. A self-rating depression scale. Archives of general psychiatry. 1965; 12: 63-70.
  49. Watson D, LA Clark and A Tellegen. Development and validation of brief measures of positive and negative affect: the PANAS scales. J Pers Soc Psychol. 1988; 54: 1063-1070.
  50. Newson JJ, D Hunter and TC Thiagarajan. The Heterogeneity of Mental Health Assessment. Frontiers in Psychiatry. 2020; 11.
  51. Dunstan DA, N Scott and AK Todd. Screening for anxiety and depression: reassessing the utility of the Zung scales. BMC Psychiatry. 2017; 17: 329.
  52. Almhdawi KA, et al. Study-related mental health symptoms and their correlates among allied health professions students. Work. 2018; 61: 391- 401.
  53. Ramón-Arbués E, et al. [Eating behavior and relationships with stress, anxiety, depression and insomnia in university students.]. Nutr Hosp. 2019; 36: 1339-1345.
  54. Oleszko A, et al. Nutrition behaviours and the occurrence of depressive symptoms among the students in the institutions of higher education in Silesia (Poland). Rocz Panstw Zakl Hig. 2019; 70: 69-77.
  55. Ramón-Arbués E, et al. [Eating behavior and relationships with stress, anxiety, depression and insomnia in university students.]. Nutr Hosp. 36: 1339-1345.
  56. El Ansari W and G Berg-Beckhoff. Nutritional Correlates of Perceived Stress among University Students in Egypt. Int J Environ Res Public Health. 2015; 12: 14164-14176.
  57. Norte Navarro AI and R Ortiz Moncada. [Spanish diet quality according to the healthy eating index]. Nutr Hosp. 2011; 26: 330-336.
  58. Sanchez-Villegas A, et al. Association of the Mediterranean dietary pattern with the incidence of depression: the Seguimiento Universidad de Navarra/ University of Navarra follow-up (SUN) cohort. Arch Gen Psychiatry. 2009; 66: 1090-1098.
  59. Chacon-Cuberos R, et al. Relationship between Academic Stress, Physical Activity and Diet in University Students of Education. Behav Sci (Basel). 2019; 9.
  60. Faghih S, et al. Adherence to the dietary approaches to stop hypertension (DASH) dietary pattern and mental health in Iranian university students. Eur J Nutr. 2020; 59: 1001-1011.
  61. Leitzmann C. Vegetarian nutrition: past, present, future. Am J Clin Nutr. 2014; 100: 496s-502s.
  62. Velten J, et al. Lifestyle choices and mental health: a longitudinal survey with German and Chinese students. BMC Public Health. 2018; 18: 632.
  63. Lavallee K, et al. Vegetarian diet and mental health: Cross-sectional and longitudinal analyses in culturally diverse samples. J Affect Disord. 2019; 248: 147-154.
  64. Sergentanis TN, et al. Vegetarian Diets and Eating Disorders in Adolescents and Young Adults: A Systematic Review. Children. 2021; 8: 12.
  65. Iguacel I, et al. Vegetarianism and veganism compared with mental health and cognitive outcomes: a systematic review and meta-analysis. Nutrition Reviews. 2020; 79: 361-381.
  66. Mikolajczyk RT, W El Ansari and AE Maxwell. Food consumption frequency and perceived stress and depressive symptoms among students in three European countries. Nutr J. 2009; 8: 31.
  67. El Ansari W, H Adetunji and R Oskrochi. Food and mental health: relationship between food and perceived stress and depressive symptoms among university students in the United Kingdom. Cent Eur J Public Health. 2014; 22: 90-97.
  68. Keck MM, et al. Examining the Role of Anxiety and Depression in Dietary Choices among College Students. Nutrients. 2020; 12.
  69. Mochimasu KD, N Miyatake and A Hase. A pilot study of the relationship between diet and mental health in female university students enrolled in a training course for registered dietitians. Environ Health Prev Med. 2016; 21: 345-349.
  70. Prohan M, et al. Total antioxidant capacity of diet and serum, dietary antioxidant vitamins intake, and serum hs-CRP levels in relation to depression scales in university male students. Redox Rep. 2014; 19: 133- 139.
  71. Liu C, et al. Perceived stress, depression and food consumption frequency in the college students of China Seven Cities. Physiol Behav. 2007; 92: 748- 754.
  72. Ugartemendia L, et al. “Influence of diet on mood and social cognition: a pilot study”. Food Funct. 2020; 11: 8320-8330.
  73. Wattick RA, RL Hagedorn and MD Olfert. Relationship between Diet and Mental Health in a Young Adult Appalachian College Population. Nutrients. 2018; 10.
  74. Raskind IG, R Haardörfer and CJ Berg. Food insecurity, psychosocial health and academic performance among college and university students in Georgia, USA. Public Health Nutr. 2019; 22: 476-485.
  75. Howard ALP and ETP Barker. Mental Health of Students Reporting Food Insecurity during the Transition to University. Can J Diet Pract Res. 2021: 1-6.
  76. Conner TS, et al. Let them eat fruit! The effect of fruit and vegetable consumption on psychological well-being in young adults: A randomized controlled trial. PLOS ONE. 2017; 12: e0171206.
  77. Adewuya AO. Prevalence of major depressive disorder in Nigerian college students with alcohol-related problems. Gen Hosp Psychiatry. 2006; 28: 169-173.
  78. Peltzer K. Depressive symptoms in relation to alcohol and tobacco use in South African university students. Psychol Rep. 2003; 92: 1097-1098.
  79. Heidke P, et al. Associations between health-related quality of life and health behaviors in Australian nursing students. Nurs Health Sci. 2021.
  80. Maes M, et al. A review on the oxidative and nitrosative stress (O&NS) pathways in major depression and their possible contribution to the (neuro) degenerative processes in that illness. Prog Neuropsychopharmacol Biol Psychiatry. 2011; 35: 676-692.
  81. Açik M and FP Çakiroglu. Evaluating the Relationship between Inflammatory Load of a Diet and Depression in Young Adults. Ecol Food Nutr. 2019; 58: 366-378.
  82. Amani R, et al. Correlation between dietary zinc intakes and its serum levels with depression scales in young female students. Biol Trace Elem Res. 2010; 137: 150-158.
  83. Park SH, et al. Relationship Among Dietary Taurine Intake, Dietary Attitudes, Dietary Behaviors, and Life Stress by Depression in Korean Female College Students. Adv Exp Med Biol. 2019; 1155: 293-300.
  84. Yary T. The association between dietary intake of folate and physical activity with psychological dimensions of depressive symptoms among students from Iran. Biomed Res Int. 2013; 2013: 582693.
  85. Stringham NT, PV Holmes and JM Stringham. Supplementation with macular carotenoids reduces psychological stress, serum cortisol, and suboptimal symptoms of physical and emotional health in young adults. Nutr Neurosci. 2018; 21: 286-296.
  86. Peltzer K and S Pengpid. Depressive symptoms and social demographic, stress and health risk behaviour among university students in 26 low-, middle- and high-income countries. International Journal of Psychiatry in Clinical Practice. 2015; 19: 259-265.
  87. Kiecolt-Glaser JK, et al. Omega-3 supplementation lowers inflammation and anxiety in medical students: a randomized controlled trial. Brain Behav Immun. 2011; 25: 1725-1734.
  88. Lindseth G, B Helland and J Caspers. The effects of dietary tryptophan on affective disorders. Archives of psychiatric nursing. 2015; 29: 102-107.
  89. Nishida K, et al. Health Benefits of Lactobacillus gasseri CP2305 Tablets in Young Adults Exposed to Chronic Stress: A Randomized, Double-Blind, Placebo-Controlled Study. Nutrients. 2019; 11.
  90. Tran N, et al. The gut-brain relationship: Investigating the effect of multispecies probiotics on anxiety in a randomized placebo-controlled trial of healthy young adults. J Affect Disord. 2019; 252: 271-277.
  91. Opie RS, et al. Dietary recommendations for the prevention of depression. Nutr Neurosci. 2017; 20: 161-171.
  92. Iguacel I, et al. Vegetarianism and veganism compared with mental health and cognitive outcomes: a systematic review and meta-analysis. Nutr Rev. 2020.
  93. Askari M, et al. Vegetarian diet and the risk of depression, anxiety, and stress symptoms: a systematic review and meta-analysis of observational studies. Critical Reviews in Food Science and Nutrition. 2020: 1-11.
  94. Dobersek U, et al. Meat and mental health: a systematic review of meat abstention and depression, anxiety, and related phenomena. Critical Reviews in Food Science and Nutrition. 2021; 61: 622-635.
  95. Quick VM and C Byrd-Bredbenner. Disturbed eating behaviours and associated psychographic characteristics of college students. J Hum Nutr Diet. 2013; 26: 53-63.
  96. James C, et al. “Safe Foods” or “Fear Foods”: the implications of food avoidance in college students from low- and middle-income countries. Eat Weight Disord. 2017; 22: 407-419.
  97. McMartin SE, et al. Diet quality and mental health in subsequent years among Canadian youth. Public Health Nutr. 2012; 15: 2253-2258.
  98. Deane KHO, et al. Omega-3 and polyunsaturated fat for prevention of depression and anxiety symptoms: systematic review and meta-analysis of randomised trials. Br J Psychiatry. 2019: 1-8.
  99. Cenit MC, Y Sanz and P Codoñer-Franch. Influence of gut microbiota on neuropsychiatric disorders. World J Gastroenterol. 2017; 23: 5486-5498.
  100. Dinan TG and JF Cryan. Melancholic microbes: a link between gut microbiota and depression? Neurogastroenterol Motil. 2013; 25: 713-719.
  101. Jiang H, et al. Altered fecal microbiota composition in patients with major depressive disorder. Brain Behav Immun. 2015; 48: 186-194.
  102. Aizawa E, et al. Possible association of Bifidobacterium and Lactobacillus in the gut microbiota of patients with major depressive disorder. J Affect Disord. 2016; 202: 254-257.
  103. Dinan TG and JF Cryan. Brain-Gut-Microbiota Axis and Mental Health. Psychosom Med. 2017; 79: 920-926.
  104. Messaoudi M, et al. Beneficial psychological effects of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in healthy human volunteers. Gut Microbes. 2011; 2: 256-261.
  105. Hughes C, et al. Galactooligosaccharide supplementation reduces stressinduced gastrointestinal dysfunction and days of cold or flu: a randomized, double-blind, controlled trial in healthy university students. Am J Clin Nutr. 2011; 93: 1305-1311.

Citation: Mantzorou M, Serdari A, Kostopoulos M and Giaginis C. Diet Quality Impacts Mental Health Aspects of University Students. Austin J Nutri Food Sci. 2021; 9(2): 1158.