Sarah R. Dash
Adrienne O’Neil2,3
Felice N. Jacka- 1IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, VIC, Australia
- 2School of Public Health and Preventive Medicine, Monash University, Prahran, VIC, Australia
- 3Alfred Hospital, School of Public Health and Preventive Medicine, Prahran, VIC, Australia
- 4Centre for Adolescent Health, Murdoch Children’s Research Centre, Parkville, VIC, Australia
- 5Department of Psychiatry, Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
- 6Black Dog Institute, Prince of Wales Hospital, Randwick, NSW, Australia
Introduction
The globalization of the food industry has lead to substantial dietary changes across developed and developing economies, comprising a shift toward the consumption of higher energy, less nutritious foods at the expense of traditional, more healthful, dietary patterns (1). These dietary changes have led to clear public health challenges as the burden of obesity and other diet-related non-communicable disorders (NCDs) continue to rise. In 2015, the Global Burden of Disease study identified unhealthy diet as the leading cause of early mortality worldwide (2). At the same time, mental and substance use disorders are recognized as the leading contributors to global disability (3). Of these, the common mental disorders (CMDs) – depression and anxiety – contribute the greatest proportion of disability, accounting for 40.5 and 14.6% of disease burden respectively. Only recently has it been recognized that unhealthy diet and CMDs are related: unhealthy diet is a significant risk factor not only for NCDs, such as cardiovascular diseases, some cancers, and diabetes, but also for CMDs (4). Dietary interventions may, thus, provide a far-reaching and low risk public health opportunity for the prevention and treatment of CMDs.
Traditionally, psychiatric epidemiology has directed much of its research efforts into understanding the etiology of psychiatric conditions and has lagged behind in the development of public health strategies for primary prevention (5). While the past decade has given rise to public health campaigns directed at mental illness, such campaigns are often focused on raising awareness and reducing stigma rather than on specific actions (6). Moreover, while several critical windows of opportunity for mental disorder prevention have been presented (7), there currently exists no clear or specific prevention strategy or recommendations for mental illness akin to that which exists for other common NCDs. Funding resources allocated to primary prevention of CMDs are greatly disproportionate to its disease burden, and resources for mental health prevention are not equitable to the priority placed on them by major stakeholders (8, 9). This paper argues the necessity of translating the new knowledge regarding the diet–depression paradigm into the development and implementation of public health and clinical intervention strategies at a population level.
CMDs and Diet
There is now consistent epidemiological evidence for associations between measures of habitual diet quality and depression, globally (10–14) and across the lifespan (15–18), which do not appear to be explained by socioeconomic circumstances (4) or reverse causality (11, 19, 20). In fact, dietary habits have now been identified as a modifiable risk factor for depression and anxiety in several recent systematic reviews (21–23). The literature suggests that a good quality diet is characterized by high consumption of fruits, vegetables, whole grains, nuts, seeds, and fish while limiting intake of processed foods (24). Evidence at the clinical trial level indeed provide promising data; two new interventions indicate that preventing depression using dietary improvement as a strategy is possible (25, 26). Another systematic review has identified preliminary evidence for dietary improvement as a treatment strategy for symptoms of CMDs (24). There are also extensive animal and human data pointing to the biological underpinnings of CMDs that are modulated by diet, with gut microbiota and inflammatory pathways gaining particularly attention (27, 28), in addition to brain plasticity pathways in humans (29). While the link between individual nutrients, supplements, and mental disorder treatment has been studied, this discussion aims to focus on prevention and treatment through a whole-of-diet approach to mental health (30–32). Results from ongoing and future intervention studies are essential to continuing to strengthen this evidence base, as well as advancing the diet–depression paradigm, and must be a funding and research priority (5).
Why Act Now?
Given the strength and consistency of the epidemiological and animal evidence, coupled with the emerging evidence from intervention studies, we contend that diet should be considered a risk factor for the onset of CMDs, with public health messages and strategies developed that build on this new understanding. These will have the added benefit of targeting the non-communicable conditions that are so commonly comorbid with CMDs and which are responsible for a significant proportion of premature deaths worldwide (33). Moreover, dietary recommendations that focus on mental health may have more salience for the public, given that the possible consequences of unhealthy diets – heart disease, diabetes, and cancer – may be perceived as distal, while mental health is a far more proximal consequence for many. This is particularly the case for young people who are especially affected by both detrimental dietary changes (34) and mental health issues (35). Although obesity may be considered a key indicator of lifestyle, most epidemiological studies in this field demonstrated that the relationship between diet and depression exists independently of body mass index (11, 20, 36). Furthermore, improvements in mood may precede weight loss and may also provide more tangible and immediate benefits that encourage sustaining health behaviors, with weight or obesity management a possible downstream benefit (37–39).
Despite advances in aspects of mental health care, researchers and clinicians have highlighted the shortfalls of pharmacological or individualized clinical to patient care for CMDs (40). While intervention studies on the diet–depression paradigm remain a priority, the current evidence base meets key Bradford Hill Criteria, with few perceivable risks to impede action (41). Given the high prevalence and burden of CMDs, even slight improvements in depression through dietary intervention or prevention strategies may translate to large gains at the population level given that diet is a variable with 100% exposure.
Implementing Dietary Improvement as a Public Health Strategy for Mental Health
There is much to be learned from previous public health movements that serve to guide the effective implementation of dietary improvement as a mental health strategy. While there is no country that has successfully managed to reverse its rising obesity trends (42), other public health campaigns that have been successful in improving health outcomes at a population level – such as folic acid supplementation during pregnancy or smoking cessation – have made changes using a top-down approach, supported by political changes to policies, practices, and taxation (43, 44). Implementing prevention strategies for mental health, and specific recommendations for how to proceed at community, academic, and government levels has been discussed in more detail elsewhere (5, 45, 46). Previous behavior change models have highlighted important periods for intervention, where targeted strategies may be more successful (47, 48). Previous research has demonstrated that in utero, early life, and adolescence are particularly important periods in determining future health and, thus, may be valuable target for public health campaigns. Given that pregnancy provides a unique “teachable moment,” where mothers are particularly open to receiving health advice and making behavior change, such a targeted approach to prevention of the CMDs may prove to be feasible (49) and have important implications for the mental health of offspring.
Poor quality diet should be included within the risk assessment for major depressive disorder (MDD) within clinical care settings, with dietary recommendations and dietetic services as central components of primary care for individuals diagnosed with depressive symptoms and MDD. Moreover, given the robust evidence base for physical activity as a protective and treatment factor in depression (50, 51), and the emerging evidence for the mental health benefits of smoking cessation (52), exercise recommendations and smoking cessation services should also be standard components of clinical care for at-risk patients and those with established CMDs. In other words, treatment for CMD should regard physical health as of equal importance as a treatment target when considering the mental health of a patient.
Barriers to Implementation
There are several key considerations for implementing public health dietary interventions for mental health. One imperative is to demonstrate clear, objective benefits to motivate both policy, local and individual health behavior change. For this, a large-scale, worldwide, case-control study that calculates the percentage population attributable risk of poor diet to the incidence of CMDs will be required; akin to those that exist for heart disease, for example, INTERHEART study (2001). Additionally, well-enacted, robust interventions demonstrating efficacy and cost-effectiveness will be critical. At least one clinical trial is currently underway (53); however, more are needed. Importantly, public health interventions aimed at reducing NCD risk factors should also assess mental health outcomes and utilize findings to assess the effectiveness and cost-effectiveness of such interventions. As noted by many strategies in the past, single-approach or single-disciplinary approaches to complex, multi-modal problems have limited success, and there are demands for both systems-based interventions and monitoring systems and laws, regulations, and taxation changes to achieve traction in improving health at the population level (54).
While some studies have demonstrated the affordability of a healthy diet (55), financial incentives may be particularly important in groups with lower socioeconomic status (56). Finally, ensuring access to healthful foods for those in remote and highly disadvantaged areas is a critical challenge that should be prioritized, particularly given the burden of physical and mental health problems in such areas in addition to issues of food access.
Conclusion
Despite increased awareness and attention, we have yet to effectively and consistency address the high prevalence and burden of CMDs. Improving diet quality has the important yet neglected potential for prevention and treatment of CMDs. Here, we contend that while intervention studies will be an essential component of this evidence base, the current understanding of the diet–CMD association calls for “consequentialist epidemiology,” with focus on the translation of diet-mental health research to action (57). Recognition of diet as a risk factor for CMDs and the development of public health strategies focused on dietary improvement are likely to positively address the global burden of both CMDs and NCDs. Effectively implementing dietary improvement as a public health strategy for mental health will require a multi-sectorial, multi-stakeholder approach (58), but offers substantial promise for improving outcomes for individuals and the wider community.
Author Contributions
SD, AO, and FJ conceptualized the paper. SD wrote the first draft of the manuscript. AO and FJ made key contributions and revisions to the final version of the manuscript.
Conflict of Interest Statement
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
References
1. Logan AC, Jacka FN. Nutritional psychiatry research: an emerging discipline and its intersection with global urbanization, environmental challenges and the evolutionary mismatch. J Physiol Anthropol (2014) 33:22. doi:10.1186/1880-6805-33-22
2. Collaborators GBDRF, Forouzanfar MH, Alexander L, Anderson HR, Bachman VF, Biryukov S, et al. Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks in 188 countries, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet (2015) 386(10010):2287–323. doi:10.1016/S0140-6736(15)00128-2
3. Whiteford HA, Degenhardt L, Rehm J, Baxter AJ, Ferrari AJ, Erskine HE, et al. Global burden of disease attributable to mental and substance use disorders: findings from the Global Burden of Disease Study 2010. Lancet (2013) 382:1575–86. doi:10.1016/S0140-6736(13)61611-6
4. Jacka FN, Cherbuin N, Anstey KJ, Butterworth P. Dietary patterns and depression symptoms over time: examining the relationships with socioeconomic position, health behaviours and cardiovascular risk. PLoS One (2014) 9(1):e87657. doi:10.1371/journal.pone.0087657
5. Jacka FN, Reavley NJ, Jorm AF, Toumbourou JW, Lewis AJ, Berk M. Prevention of common mental disorders: what can we learn from those who have gone before and where do we go next? Aust N Z J Psychiatry (2013) 47(10):920–9. doi:10.1177/0004867413493523
6. Dumesnil H, Verger P. Public awareness campaigns about depression and suicide: a review. Psychiatr Serv (2009) 60(9):1203–13. doi:10.1176/appi.ps.60.9.1203
7. Shonkoff JP, Boyce WT, McEwen BS. Neuroscience, molecular biology, and the childhood roots of health disparities: building a new framework for health promotion and disease prevention. JAMA (2009) 301(21):2252–9. doi:10.1001/jama.2009.754
8. Christensen H, Batterham PJ, Griffiths KM, Gosling J, Hehir KK. Research priorities in mental health. Aust N Z J Psychiatry (2013) 47(4):355–62. doi:10.1177/0004867412474072
9. Prince M, Patel V, Saxena S, Maj M, Maselko J, Phillips MR, et al. No health without mental health. Lancet (2007) 370(9590):859–77. doi:10.1016/S0140-6736(07)61238-0
10. Nanri A, Kimura Y, Matsushita Y, Ohta M, Sato M, Mishima N, et al. Dietary patterns and depressive symptoms among Japanese men and women. Eur J Clin Nutr (2010) 64(8):832–9. doi:10.1038/ejcn.2010.86
11. Jacka FN, Kremer PJ, Leslie ER, Berk M, Patton GC, Toumbourou JW, et al. Associations between diet quality and depressed mood in adolescents: results from the Australian Healthy Neighbourhoods Study. Aust N Z J Psychiatry (2010) 44(5):435–42.
12. Belal NM. The relation between diet and behavioural problems in Kuwaiti adolescents. J Appl Sci Res (2012) 8(8):4051–7.
13. Muñoz MA, Fíto M, Marrugat J, Covas MI, Schröder H, REGICOR and HERMES Investigators. Adherence to the Mediterranean diet is associated with better mental and physical health. Br J Nutr (2009) 101(12):1821–7. doi:10.1017/S0007114508143598
14. Jacka FN, Kremer PJ, Berk M, de Silva-Sanigorski AM, Moodie M, Leslie ER, et al. A prospective study of diet quality and mental health in adolescents. PLoS One (2011) 6(9):e24805. doi:10.1371/journal.pone.0024805
15. Oellingrath IM, Svendsen MV, Hestetun I. Eating patterns and mental health problems in early adolescence – a cross-sectional study of 12-13-year-old Norwegian schoolchildren. Public Health Nutr (2014) 17(11):2554–62. doi:10.1017/S1368980013002747
16. Steenweg-de Graaff J, Tiemeier H, Steegers-Theunissen RP, Hofman A, Jaddoe VW, Verhulst FC, et al. Maternal dietary patterns during pregnancy and child internalising and externalising problems. The Generation R Study. Clin Nutr (2014) 33(1):115–21. doi:10.1016/j.clnu.2013.03.002
17. Wiles NJ, Northstone K, Emmett P, Lewis G. ‘Junk food’ diet and childhood behavioural problems: results from the ALSPAC cohort. Eur J Clin Nutr (2009) 63(4):491–8. doi:10.1038/sj.ejcn.1602967
18. Payne ME, Steck SE, George RR, Steffens DC. Fruit, vegetable, and antioxidant intakes are lower in older adults with depression. J Acad Nutr Diet (2012) 112(12):2022–7. doi:10.1016/j.jand.2012.08.026
19. Jacka FN, Cherbuin N, Anstey KJ, Butterworth P. Does reverse causality explain the relationship between diet and depression? J Affect Disord (2015) 175:248–50. doi:10.1016/j.jad.2015.01.007
20. Sánchez-Villegas A, Delgado-Rodríguez M, Alonso A, Schlatter J, Lahortiga F, Serra Majem L, 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(10):1090–8. doi:10.1001/archgenpsychiatry.2009.129
21. Lai JS, Hiles S, Bisquera A, Hure AJ, McEvoy M, Attia J. A systematic review and meta-analysis of dietary patterns and depression in community-dwelling adults. Am J Clin Nutr (2014) 99(1):181–97. doi:10.3945/ajcn.113.069880
22. Psaltopoulou T, Sergentanis TN, Panagiotakos DB, Sergentanis IN, Kosti R, Scarmeas N. Mediterranean diet, stroke, cognitive impairment, and depression: a meta-analysis. Ann Neurol (2013) 74(4):580–91. doi:10.1002/ana.23944
23. Quirk SE, Williams LJ, O’Neil A, Pasco JA, Jacka FN, Housden S, et al. The association between diet quality, dietary patterns and depression in adults: a systematic review. BMC Psychiatry (2013) 13:175. doi:10.1186/1471-244X-13-175
24. Opie RS, O’Neil A, Itsiopoulos C, Jacka FN. The impact of whole-of-diet interventions on depression and anxiety: a systematic review of randomised controlled trials. Public Health Nutr (2015) 18(11):2074–93. doi:10.1017/S1368980014002614
25. Sánchez-Villegas A, Martínez-González MA, Estruch R, Salas-Salvadó J, Corella D, Covas MI, et al. Mediterranean dietary pattern and depression: the PREDIMED randomized trial. BMC Med (2013) 11:208. doi:10.1186/1741-7015-11-208
26. Stahl ST, Albert SM, Dew MA, Lockovich MH, Reynolds CF III. Coaching in healthy dietary practices in at-risk older adults: a case of indicated depression prevention. Am J Psychiatry (2014) 171(5):499–505. doi:10.1176/appi.ajp.2013.13101373
27. Berk M, Williams LJ, Jacka FN, O’Neil A, Pasco JA, Moylan S, et al. So depression is an inflammatory disease, but where does the inflammation come from? BMC Med (2013) 11:200. doi:10.1186/1741-7015-11-200
28. Cryan JF, Dinan TG. Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour. Nat Rev Neurosci (2012) 13(10):701–12. doi:10.1038/nrn3346
29. Jacka FN, Cherbuin N, Anstey KJ, Sachdev P, Butterworth P. Western diet is associated with a smaller hippocampus: a longitudinal investigation. BMC Med (2015) 13:215. doi:10.1186/s12916-015-0461-x
30. Bloch MH, Hannestad J. Omega-3 fatty acids for the treatment of depression: systematic review and meta-analysis. Mol Psychiatry (2012) 17(12):1272–82. doi:10.1038/mp.2011.100
31. Lai J, Moxey A, Nowak G, Vashum K, Bailey K, McEvoy M. The efficacy of zinc supplementation in depression: systematic review of randomised controlled trials. J Affect Disord (2012) 136(1–2):e31–9. doi:10.1016/j.jad.2011.06.022
32. Sarris J, Logan AC, Akbaraly TN, Paul Amminger G, Balanzá-Martínez V, Freeman MP, et al. International Society for Nutritional Psychiatry Research consensus position statement: nutritional medicine in modern psychiatry. World Psychiatry (2015) 14(3):370–1. doi:10.1002/wps.20223
33. Lozano R, Naghavi M, Foreman K, Lim S, Shibuya K, Aboyans V, et al. Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet (2012) 380(9859):2095–128. doi:10.1016/S0140-6736(12)61728-0
34. Nielsen SJ, Siega-Riz AM, Popkin BM. Trends in food locations and sources among adolescents and young adults. Prev Med (2002) 35(2):107–13. doi:10.1006/pmed.2002.1037
35. Kessler RC, Berglund P, Demler O, Jin R, Merikangas KR, Walters EE. Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Comorbidity Survey Replication. Arch Gen Psychiatry (2005) 62(6):593–602. doi:10.1001/archpsyc.62.6.617
36. Akbaraly TN, Brunner EJ, Ferrie JE, Marmot MG, Kivimaki M, Singh-Manoux A. Dietary pattern and depressive symptoms in middle age. Br J Psychiatry (2009) 195(5):408–13. doi:10.1192/bjp.bp.108.058925
37. McMillan L, Owen L, Kras M, Scholey A. Behavioural effects of a 10-day Mediterranean diet. Results from a pilot study evaluating mood and cognitive performance. Appetite (2011) 56(1):143–7. doi:10.1016/j.appet.2010.11.149
38. Asmundson GJ, Fetzner MG, Deboer LB, Powers MB, Otto MW, Smits JA. Let’s get physical: a contemporary review of the anxiolytic effects of exercise for anxiety and its disorders. Depress Anxiety (2013) 30(4):362–73. doi:10.1002/da.22043
39. Fabricatore AN, Wadden TA, Higginbotham AJ, Faulconbridge LF, Nguyen AM, Heymsfield SB, et al. Intentional weight loss and changes in symptoms of depression: a systematic review and meta-analysis. Int J Obes (Lond) (2011) 35(11):1363–76. doi:10.1038/ijo.2011.2
40. Kazdin AE, Blase SL. Rebooting psychotherapy research and practice to reduce the burden of mental illness. Perspect Psychol Sci (2011) 6(1):21–37. doi:10.1177/1745691610393527
41. Lucas RM, McMichael AJ. Association or causation: evaluating links between “environment and disease”. Bull World Health Organ (2005) 83(10):792–5.
42. Lang T, Rayner G. Overcoming policy cacophony on obesity: an ecological public health framework for policymakers. Obes Rev (2007) 8(Suppl 1):165–81. doi:10.1111/j.1467-789X.2007.00338.x
43. Obican SG, Finnell RH, Mills JL, Shaw GM, Scialli AR. Folic acid in early pregnancy: a public health success story. FASEB J (2010) 24(11):4167–74. doi:10.1096/fj.10-165084
44. Holford TR, Meza R, Warner KE, Meernik C, Jeon J, Moolgavkar SH, et al. Tobacco control and the reduction in smoking-related premature deaths in the United States, 1964-2012. JAMA (2014) 311(2):164–71. doi:10.1001/jama.2013.285112
45. Patel V, Belkin GS, Chockalingam A, Cooper J, Saxena S, Unützer J. Grand challenges: integrating mental health services into priority health care platforms. PLoS Med (2013) 10(5):e1001448. doi:10.1371/journal.pmed.1001448
46. O’Neil A, Jacka FN, Quirk SE, Cocker F, Taylor CB, Oldenburg B, et al. A shared framework for the common mental disorders and non-communicable disease: key considerations for disease prevention and control. BMC Psychiatry (2015) 15:15. doi:10.1186/s12888-015-0394-0
47. Sawyer SM, Afifi RA, Bearinger LH, Blakemore SJ, Dick B, Ezeh AC, et al. Adolescence: a foundation for future health. Lancet (2012) 379(9826):1630–40. doi:10.1016/S0140-6736(12)60072-5
48. Barouki R, Gluckman PD, Grandjean P, Hanson M, Heindel JJ. Developmental origins of non-communicable disease: implications for research and public health. Environ Health (2012) 11:42. doi:10.1186/1476-069X-11-42
49. O’Neil A, Itsiopoulos C, Skouteris H, Opie RS, McPhie S, Hill B, et al. Preventing mental health problems in offspring by targeting dietary intake of pregnant women. BMC Med (2014) 12:208. doi:10.1186/s12916-014-0208-0
50. Rosenbaum S, Tiedemann A, Sherrington C, Curtis J, Ward PB. Physical activity interventions for people with mental illness: a systematic review and meta-analysis. J Clin Psychiatry (2014) 75(9):964–74. doi:10.4088/JCP.13r08765
51. Mammen G, Faulkner G. Physical activity and the prevention of depression: a systematic review of prospective studies. Am J Prev Med (2013) 45(5):649–57. doi:10.1016/j.amepre.2013.08.001
52. Taylor G, McNeill A, Girling A, Farley A, Lindson-Hawley N, Aveyard P. Change in mental health after smoking cessation: systematic review and meta-analysis. BMJ (2014) 348:g1151. doi:10.1136/bmj.g1151
53. O’Neil A, Berk M, Itsiopoulos C, Castle D, Opie R, Pizzinga J, et al. A randomised, controlled trial of a dietary intervention for adults with major depression (the “SMILES” trial): study protocol. BMC Psychiatry (2013) 13:114. doi:10.1186/1471-244X-13-114
54. Jacka FN, Sacks G, Berk M, Allender S. Food policies for mental and physical health. BMC Psychiatry (2014) 14:132. doi:10.1186/1471-244X-14-132
55. Opie RS, Segal L, Jacka FN, Nicholls L, Dash S, Pizzinga J, et al. Assessing healthy diet affordability in a cohort with major depressive disorders. Publ Health Epidemiol (2015) 7(5):159–69. doi:10.5897/JPHE2014.0668
56. Wong KC, Coveney J, Ward P, Muller R, Carter P, Vertiy F, et al. Availability, affordability and quality of a healthy food basket in Adelaide, South Australian. Nutr Diet (2011) 68:8–14. doi:10.1111/j.1747-0080.2010.01490.x
57. Galea S. An argument for a consequentialist epidemiology. Am J Epidemiol (2013) 178(8):1185–91. doi:10.1093/aje/kwt172
Keywords: diet, mental health, public health, prevention, epidemiology
Citation: Dash SR, O’Neil A and Jacka FN (2016) Diet and Common Mental Disorders: The Imperative to Translate Evidence into Action. Front. Public Health 4:81. doi: 10.3389/fpubh.2016.00081
Received: 04 February 2016; Accepted: 13 April 2016;
Published: 29 April 2016
Edited by:
Andrew Kemp, Swansea University, UKReviewed by:
Julian Koenig, Heidelberg University, GermanyLaura Louise Wilkinson, Swansea University, UK
Hayley Anne Young, Swansea University, UK
Copyright: © 2016 Dash, O’Neil and Jacka. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Felice N. Jacka, f.jacka@deakin.edu.au