Nutrition and Mental Health

Two Women On Diet Preparing Vegetables in Kitchen

In times of uncertainty, robust mental health may be challenging to cultivate and maintain. Traumatic events and difficult circumstances that affect a population have often been followed by increases in a range of mental and behavioral illnesses, including depression and posttraumatic stress disorder (PTSD).1 Clinical strategies that include nutrition interventions have potentially powerful impacts, not only for chronic mental health disorders, but also for a patient’s overall mental wellness.

Diet Quality and Mental Health

Depression is a leading cause of disability worldwide,2 and in the United States, anxiety disorders are common, affecting approximately 40 million adults every year.3 Psychotherapy approaches and medications are standard first-line treatments suggested for clinical depression and general anxiety disorders.4,5 In addition, the emerging field of nutritional psychiatry suggests a relationship between diet quality and mental health and considers the use of dietary and nutraceutical interventions to address mental disorders and to potentially improve patient outcomes.6,7 Recent research suggests that while nutritional habits, dietary patterns, and diet quality may all impact overall mental wellness, they may also be modifiable risk factors for mental disorders.6,8-10 For example, conclusions based largely on cross-sectional and longitudinal studies suggest that routine consumption of a Western-type highly processed diet increased the risk of developing symptoms associated with depression and anxiety.8 In contrast, those observational studies suggested that the risk was lower if an anti-inflammatory, Mediterranean-style diet was followed.8

In this video, Kristi Hughes, ND, IFMCP shares her approach and initial questions for patients who present with symptoms related to depression. She also explains why she typically starts treatment with a nutrition intervention.

Mental Wellness: Prevention and Treatment of Disorders

A balanced diet of vegetables, fruits, healthy fats, lean proteins, and whole grains may help bolster mental wellness for management of daily life stresses, anxiety, and grief.11,12 Further, dietary patterns such as regularly scheduled meals may also prevent mental health issues.10 For clinical treatments, research continues to suggest that foods, nutrients, and overall diet quality have the potential to ease symptoms of mental disorders and improve patient outcomes.

Bipolar Disorder: Mitochondrial support and omega-3

The pathophysiology of bipolar disorder has not been specified; however, promoting mitochondrial function and enhancing dietary quality may provide therapeutic benefit and alleviate some depressive symptoms.7,13 A double-blind randomized controlled trial (RCT) with 181 participants with bipolar depression found no difference between groups that were either treated with 2,000 mg/day of N-acetylcysteine (NAC), a potential agent for mitochondrial biogenesis, NAC plus a combination of nutrient agents, or placebo.7 Yet a sub-study of the RCT assessed diet quality and found that participants with better diet quality reported reduced general depression and bipolar symptoms and had greater clinician-rated improvements, regardless of the experiment treatment received.14 Further, researchers suggested that the combination treatment that included additional mitochondria-supporting nutrients potentially tampered any adverse effects of pro-inflammatory diets on participants’ reported cognitive function.14

The American Psychiatric Association recommends omega-3 supplementation as an adjunctive therapy for mood disorders, including bipolar depression, noting potentially greater efficacy with treatments of eicosapentaenoic acid (EPA) alone or EPA and docosahexaenoic acid (DHA) together if EPA dosage levels are higher in the combination.15 To test efficacy of DHA alone, a recent RCT explored DHA as a monotherapy for bipolar disorder, and although the trial was small, with 31 participants with bipolar disorder and 15 healthy controls, researchers found that after 12 weeks of DHA supplementation (1,250 mg daily) versus a placebo of corn oil, no significant differences between the groups on cognitive functions were reported except for testing of emotional inhibition.16

Healthy dietary patterns and higher-quality diets have been associated with lower levels of depression and better mental health in children and adults.8,17-19

Depression: Overall Diet quality

Adherence to a Mediterranean-style diet has been associated with a reduction in the risk of developing depression. Improving diet quality has also been investigated as a potential treatment for depression with promising results. Two smaller RCTs from 2017 found that improving overall diet quality by adhering to a Mediterranean-style diet reduced depression symptoms for study participants.9,19 In fact, one of the studies included only participants with both major depressive disorder and a diet history that was rated as “poor quality” and found that 32% of participants in the dietary intervention group, which improved their diet quality, achieved a remission of depressive episodes within the three-month intervention period.19 While studies investigating improved dietary quality have suggested positive outcomes for patients with depression, results from a 2019 RCT indicated that treatment with only a multi-nutrient supplement did not significantly reduce depressive or anxiety symptoms.20

A Bidirectional Caveat

The relationship between nutrition and mental health has also been discussed as bidirectional, with dietary choices not only possibly impacting mental wellness, but mental health states potentially affecting dietary habits and food choices.21,22 Specific to depression and anxiety, the role of the gut-brain axis and status of the gut microbiota has recently surfaced as a potential consideration and component for future diet-depression research studies and clinical nutrition interventions.23

Clinical Applications

In functional medicine, personalized nutrition interventions are key components to therapeutic strategies that address chronic mental health issues and a patient’s overall mental wellness. Considering a patient’s lifestyle factors and imbalances helps to identify the root cause of their mental health issue, and tools such as IFM’s nutrition-oriented physical exam help to identify inadequate nutrients. IFM’s modifiable food plans such as the Elimination Diet and the Mitochondrial Food Plan are additional resources used by functional medicine practitioners to enhance cognitive health and address inflammatory concerns.

Dietary changes can seem challenging to many patients, especially those with mental health issues. Learn more about tools and strategies to help patients achieve sustainable lifestyle change and improve their well-being through IFM’s new course Lifestyle: The Foundations of Functional Medicine.

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For more information on nutrition and mental health, please read the following IFM-authored articles.

Lifestyle Alternative to Antidepressants

One Clinician’s Take on Factors That Contribute to Depression Symptoms

Related Insights


  1. Galea S, Merchant RM, Lurie N. The mental health consequences of COVID-19 and physical distancing: the need for prevention and early intervention. JAMA Intern Med. Published online April 10, 2020. doi:10.1001/jamainternmed.2020.1562
  2. World Health Organization. Depression fact sheet. Published January 30, 2020. Accessed March 31, 2020.
  3. Anxiety and Depression Association of America. Facts & statistics. Accessed March 31, 2020.
  4. Anxiety and Depression Association of America. Clinical practice overview for GAD. Revised July 2, 2015. Accessed March 31, 2020.
  5. National Institute of Mental Health. Depression. Revised February 2018. Accessed March 31, 2020.
  6. Marx W, Moseley, Berk M, Jacka F. Nutritional psychiatry: the present state of the evidence. Proc Nutr Soc. 2017;76(4):427-436. doi:10.1017/S0029665117002026
  7. Berk M, Turner A, Malhi GS, et al. A randomised controlled trial of a mitochondrial therapeutic target for bipolar depression: mitochondrial agents, N-acetylcysteine, and placebo. BMC Med. 2019;17(1):18. doi:10.1186/s12916-019-1257-1
  8. Owen L, Corfe B. The role of diet and nutrition on mental health and wellbeing. Proc Nutr Soc. 2017;76(4):425-426. doi:10.1017/S0029665117001057
  9. Parletta N, Zarnowiecki D, Cho J, et al. A Mediterranean-style dietary intervention supplemented with fish oil improves diet quality and mental health in people with depression: a randomized controlled trial (HELFIMED). Nutr Neurosci. 2019;22(7):474-487. doi:10.1080/1028415X.2017.1411320
  10. Wilson JE, Blizzard L, Gall SL, et al. An eating pattern characterised by skipped or delayed breakfast is associated with mood disorders among an Australian adult cohort. Psychol Med. Published online October 16, 2019. doi:10.1017/S0033291719002800
  11. Sawchuk CN. Coping with anxiety: can diet make a difference? Mayo Clinic. Published May 24, 2017. Accessed March 26, 2020.
  12. Harvard Health Publishing. A guide to getting through grief. Harvard Mental Health Letter. Published December 2011. Accessed March 26, 2020.
  13. Pereira C, Chavarria V, Vian J, et al. Mitochondrial agents for bipolar disorder. Int J Neuropsychopharmacol. 2018;21(6):550-569. doi:10.1093/ijnp/pyy018
  14. Ashton MM, Dean OM, Marx W, et al. Diet quality, dietary inflammatory index and body mass index as predictors of response to adjunctive N-acetylcysteine and mitochondrial agents in adults with bipolar disorder: a sub-study of a randomised placebo-controlled trial. Aust N Z J Psychiatry. 2020;54(2):159-172. doi:10.1177/0004867419882497
  15. Task Force on Complementary and Alternative Medicine. Complementary and alternative medicine in major depressive disorder: the American Psychiatric Association Task Force assessment of the evidence, challenges, and recommendations. American Psychiatric Association. Published June 2009. Accessed March 26, 2020. Library/Psychiatrists/Directories/Library-and-Archive/resource_documents/rd2009_CAM.pdf
  16. Ciappolino V, DelVecchio G, Prunas C, et al. The effect of DHA supplementation on cognition in patients with bipolar disorder: an exploratory randomized control trial. Nutrients. 2020;12(3):E708. doi:10.3390/nu12030708
  17. 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):580-591. doi:10.1002/ana.23944
  18. Khalid S, Williams CM, Reynolds SA. Is there an association between diet and depression in children and adolescents? A systematic review. Br J Nutr. 2016;116(12):2097-2108. doi:10.1017/S0007114516004359
  19. Jacka FN, O’Neil A, Opie R, et al. A randomised controlled trial of dietary improvement for adults with major depression (the ‘SMILES’ trial). BMC Med. 2017;15(1):23. doi:10.1186/s12916-017-0791-y
  20. Bot M, Brouwer IA, Roca M, et al. Effect of multinutrient supplementation and food-related behavioral activation therapy on prevention of major depressive disorder among overweight or obese adults with subsyndromal depressive symptoms: the MooDFOOD randomized clinical trial. JAMA. 2019;321(9):858-868. doi:10.1001/jama.2019.0556
  21. van der Pols JC. Nutrition and mental health: bidirectional associations and multidimensional measures. Public Health Nutr. 2018;21(5):829-830. doi:10.1017/S1368980017003974
  22. Hibbeln JR, Northstone K, Evans J, Golding J. Vegetarian diets and depressive symptoms among men. J Affect Disord. 2018;225:13-17. doi:10.1016/j.jad.2017.07.051
  23. Bear TLK, Dalziel JE, Coad J, Roy NC, Butts CA, Gopal PK. The role of the gut microbiota in dietary interventions for depression and anxiety. Adv Nutr. Published online March 9, 2020. doi:10.1093/advances/nmaa016

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