Nutrition and Mental Health

Top view of beans and hummus dips in bowls on a bright yellow background shows that nutrition interventions may be beneficial treatments for depression and mental health disorders.

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Read Time: 4 Minutes

Depression is a common mental disorder affecting an estimated 5% of the world population.1 In the United States, depression and anxiety disorders are common, affecting millions of people of all ages.2,3 Psychotherapy approaches and medications are standard first-line treatments suggested for clinical depression and general anxiety disorders.4 In addition, clinical strategies that include nutrition interventions may have powerful impacts, not only for chronic mental health disorders but also for a patient’s overall mental wellness.

The emerging field of nutritional psychiatry suggests a positive relationship between diet quality and mental health.5 Recent research suggests that while nutritional habits, dietary patterns, and diet quality may all effect overall mental wellness, they may also be modifiable risk factors for mental disorders.6-8 For example, a 2022 meta-analysis of 17 observational studies (n=385,541 total participants) found that greater consumption of ultra-processed foods was cross-sectionally associated with increased odds of depressive and anxiety symptoms (OR:1.53; CI 1.43-1.63).8 In contrast, recent systematic reviews have indicated that increased intake of fruits and vegetables may be beneficial for overall mental wellness.9,10

(Video Time: 3 minutes) 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

While reducing processed foods and increasing antioxidant-rich fruits and vegetables may help bolster mental wellness, dietary patterns such as regularly scheduled meals may also help prevent mental health issues.7,11 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.12,13

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.14-16 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.17 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.15 Further, researchers suggested that the combination treatment that included additional mitochondria-supporting nutrients potentially tempered any adverse effects of pro-inflammatory diets on participants’ reported cognitive function.15

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.18 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.19

Healthy dietary patterns and higher-quality diets have been associated with lower levels of depression and better mental health in children and adults.10,20-22


Depression: Overall Diet quality

Adherence to a Mediterranean-style diet has been associated with a reduction in the risk of developing depression.12 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.6,21 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.21

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.23,24 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.25

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 conditions. Learn more about tools and strategies to help patients achieve sustainable lifestyle change and improve their well-being at IFM’s Annual Functional Medicine Conference. This year’s event features a specialized focus area on personalized nutrition with curated sessions by the American Nutrition Association (ANA).



Related Articles

Adjunct Therapies for Depression: More Treatment Options

Nutrition: A Key Modulator of Cognitive Health

Lifestyle Changes for Shifting Cortisol Levels

Related Insights



  1. World Health Organization. Depressive disorder (depression). WHO. Published March 31, 2023. Accessed July 18, 2023.
  2. Anxiety and Depression Association of America. Anxiety disorders – facts & statistics. ADAA. Updated October 28, 2022. Accessed July 18, 2023.
  3. Anxiety & Depression Association of America. What is depression? ADAA. Updated January 18, 2023. Accessed July 18, 2023.
  4. National Institute of Mental Health. Depression. NIMH. Revised April 2023. Accessed July 18, 2023.
  5. Adan RAH, van der Beek EM, Buitelaar JK, et al. Nutritional psychiatry: towards improving mental health by what you eat. Eur Neuropsychopharmacol. 2019;29(12):1321-1332. doi:1016/j.euroneuro.2019.10.011
  6. 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:1080/1028415X.2017.1411320
  7. 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. 2020;50(16):2711-2721. doi:1017/S0033291719002800
  8. Lane MM, Gamage E, Travica N, et al. Ultra-processed food consumption and mental health: a systematic review and meta-analysis of observational studies. Nutrients. 2022;14(13):2568. doi:3390/nu14132568
  9. Guzek D, Gla Bska D, Groele B, Gutkowska K. Fruit and vegetable dietary patterns and mental health in women: a systematic review. Nutr Rev. 2022;80(6):1357-1370. doi:1093/nutrit/nuab007
  10.  Glabska D, Guzek D, Groele B, Gutkowska K. Fruit and vegetable intake and mental health in adults: a systematic review. Nutrients. 2020;12(1):115. doi:3390/nu12010115
  11.  Zahedi H, Djalalinia S, Sadeghi O, et al. Breakfast consumption and mental health: a systematic review and meta-analysis of observational studies. Nutr Neurosci. 2022;25(6):1250-1264. doi:1080/1028415X.2020.1853411
  12.  Lassale C, Batty GD, Baghdadli A, et al. Healthy dietary indices and risk of depressive outcomes: a systematic review and meta-analysis of observational studies [published correction appears in Mol Psychiatry. 2019;24(7):1094] [published correction appears in Mol Psychiatry. 2021;26(7):3657]. Mol Psychiatry. 2019;24(7):965-986. doi:1038/s41380-018-0237-8
  13.  Guu TW, Mischoulon D, Sarris J, et al. International Society for Nutritional Psychiatry Research Practice guidelines for omega-3 fatty acids in the treatment of major depressive disorder. Psychother Psychosom. 2019;88(5):263-273. doi:1159/000502652
  14.  Madireddy S, Madireddy S. Therapeutic interventions to mitigate mitochondrial dysfunction and oxidative stress-induced damage in patients with bipolar disorder. Int J Mol Sci. 2022;23(3):1844. doi:3390/ijms23031844
  15.  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 randomized placebo-controlled trial. Aust N Z J Psychiatry. 2020;54(2):159-172. doi:1177/0004867419882497
  16.  Gabriel FC, Oliveira M, Bruna De M Martella, et al. Nutrition and bipolar disorder: a systematic review. Nutr Neurosci. 2023;26(7):637-651. doi:1080/1028415X.2022.2077031
  17.  Berk M, Turner A, Malhi GS, et al. A randomized controlled trial of a mitochondrial therapeutic target for bipolar depression: mitochondrial agents, N-acetylcysteine, and placebo. BMC Med. 2019;17(1):18. doi:1186/s12916-019-1257-1
  18.  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 July 18, 2023. Library/Psychiatrists/Directories/Library-and-Archive/resource_documents/rd2009_CAM.pdf
  19.  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:3390/nu12030708
  20.  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:1017/S0007114516004359
  21.  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:1186/s12916-017-0791-y
  22.  Glabska D, Guzek D, Groele B, Gutkowska K. Fruit and vegetables intake in adolescents and mental health: a systematic review. Rocz Panstw Zakl Hig. 2020;71(1):15-25. doi:32394/rpzh.2019.0097
  23.  van der Pols JC. Nutrition and mental health: bidirectional associations and multidimensional measures. Public Health Nutr. 2018;21(5):829-830. doi:1017/S1368980017003974
  24.  Hibbeln JR, Northstone K, Evans J, Golding J. Vegetarian diets and depressive symptoms among men. J Affect Disord. 2018;225:13-17. doi:1016/j.jad.2017.07.051
  25.  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. 2020;11(4):890-907. doi:1093/advances/nmaa016

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