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Can Diet Treat Depression?

Can Diet Treat Depression?


  • Although supported by basic science, it’s still a sea change to think that diet can treat depression. A new clinical trial puts that idea to the test. View the slides in PDF format.


  • I once worked with a man with unremitting bipolar II depression who had not responded to over a dozen medication trials. One day he strolled in with a bright affect and renewed interest in life. Perplexed, I asked him what had made the difference. “I gave up fast food a few months ago,” he said.


  • Recently, the first randomized controlled trial to test that hypothesis in unipolar depression was released. Using a modified version of the Mediterranean diet, Australian researchers randomized 67 patients with moderate to severe depression to 3 months of either dietary counseling or supportive therapy as an add-on to their usual care. The dietary approach outperformed supportive therapy, with an impressive effect size of 1.16.[1] To put that in perspective, it’s similar to the effect size of amphetamine salts in ADHD (1.0), and larger than that for modern antidepressants in major depression (0.3).[2,3]


  • Although supported by large epidemiologic and basic science studies,[1] the idea that diet can treat depression still feels like a sea change for psychiatry. The small sample size and lack of replication are reasons to be skeptical. The researchers also worked with an enriched sample, recruiting subjects whose diet was poor to begin with, so the results may not generalize to those who are already eating well.


  • The authors did take care to ensure that factors other than diet did not account for the improvement. Healthy diets can trigger a virtuous cycle of other mood-lifting changes, and they controlled for weight loss, perceived self-efficacy, physical activity, and nicotine use. Both groups received 7 hour-long sessions and placebo-enhancing rationales for their assigned interventions.


  • The actual intervention was a simplified version of the Mediterranean diet called the ModiMedDiet.[4] It does not restrict calories, but encourages more vegetables, fruits, nuts, beans, whole grains, fish, lean meats, and healthy oils; and less fried, fast, or processed foods and simple sugars. Moderate red meat consumption was encouraged, based on epidemiologic studies that link both excessive and restrictive intake of red meat to depression.


  • The fact that these depressed patients were able to make significant changes to their diet is remarkable in itself. Patients who are short on such motivation may be encouraged to know that small changes can also make a difference. Flavanol-rich foods, such as dark chocolate, green and black teas, and berries, improve mood and cognition through neuroprotective effects.[5-7] In a recent study of older adults, just a quarter cup of concentrated blueberry juice a day improved cognitive function after 3 months (randomized, controlled design; n=26).[8]


  • More examples of small dietary changes:

    • Just 2 extra servings a day of fruits and vegetables can enhance motivation and vitality, according to a controlled trial in healthy young adults.[9]

    • Even partial adherence to the Mediterranean diet lowers the risk of dementia (though full adherence brings greater benefit).[10]

    • Daily intake of probiotics, whether through diet or supplements, reduces depression and anxiety.[11]


  • Another adaptation of the Mediterranean diet that is gaining popularity is the MIND Diet, which slows cognitive decline and prevents dementia.[10,12] U.S. News recently ranked this diet No. 3 in its list of top diets for health (No. 1 and No. 2 are the plans that the MIND Diet is based on: the DASH and the Mediterranean). The MIND and ModiMed diets are very similar, so I blended them together in a brief guide for patients.


  • Both of these brain diets allow 1 to 2 standard drinks of alcohol a day, with a preference for red wine. That recommendation might need adjustment in light of new research linking even moderate levels in the 1 to 2 daily drink range to hippocampal atrophy.[13] The creator of the MIND diet plans to remove alcohol in her next trial.


  • It’s not known whether the Mediterranean diet will have similar benefits in bipolar depression, but with its neuroprotective effects it’s a good bet that it will. Even if this diet doesn’t lift mood, there are good reasons to recommend it for bipolar disorder as well, given the high rates of cognitive and metabolic problems in that population.[14]


  • The future psychiatrist may need to know as much about food as pharmacology. For now, it’s enough to know that basic, sensible dietary changes can make a significant difference for both physical and mental health.


  • Dr. Aiken is the Director of the Mood Treatment Center and an Instructor in Clinical Psychiatry at the Wake Forest University School of Medicine. He does not accept honoraria from pharmaceutical companies but receives honoraria from W.W. Norton & Co. for Bipolar, Not So Much, which he coauthored with James Phelps, MD.

View the slides in PDF format.

REFERENCES

1. 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;15:23.

2. Faraone SV, Biederman J, Spencer TJ, et al. Comparing the efficacy of medications for ADHD using meta-analysis. MedGenMed. 2006;8:4.

3. Turner EH, Rosenthal R. Efficacy of antidepressants. BMJ. 2008;336:516-517.

4. Opie RS, O’Neil A, Jacka FN, et al. A modified Mediterranean dietary intervention for adults with major depression: dietary protocol and feasibility data from the SMILES trial. Nutr Neurosci. 2017;19:1-15.

5. Chang SC, Cassidy A, Willett WC, et al. Dietary flavonoid intake and risk of incident depression in midlife and older women. Am J Clin Nutr. 2016;104:704-714.

6. Dong X, Yang C, Cao S, et al. Tea consumption and the risk of depression: a meta-analysis of observational studies. Aust N Z J Psychiatry. 2015;49:334-345.

7. Grassi D, Socci V, Tempesta D, et al. Flavanol-rich chocolate acutely improves arterial function and working memory performance counteracting the effects of sleep deprivation in healthy individuals. J Hypertens. 2016;34:1298-1308.

8. Bowtell JL, Aboo-Bakkar Z, Conway ME, et al. Enhanced task-related brain activation and resting perfusion in healthy older adults after chronic blueberry supplementation. Appl Physiol Nutr Metab. 2017;42:773-779.

9. Conner TS, Brookie KL, Carr AC, 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.

10. Morris MC, Tangney CC, Wang Y, et al. MIND diet associated with reduced incidence of Alzheimer's disease. Alzheimers Dement. 2015;11:1007-1014.

11. Wallace CJK, Milev R. The effects of probiotics on depressive symptoms in humans: a systematic review. Ann Gen Psychiatry. 2017;16:14.

12. Morris MC, Tangney CC, Wang Y, et al. MIND diet slows cognitive decline with aging. Alzheimers Dement. 2015;11:1015-1022.

13. Topiwala A, Allan CL, Valkanova V, et al. Moderate alcohol consumption as risk factor for adverse brain outcomes and cognitive decline: longitudinal cohort study. BMJ. 2017;357:j2353.

14. Beyer JL, Payne ME. Nutrition and bipolar depression. Psychiatr Clin North Am. 2016;39:75-86.

 

Comments

As a psych nurse for 3 decades, encouraging patients to eat more fruits and veggies, more fish, less red meat, and minimal salts and preservatives not only makes a person feel "cleaner", but also makes a person feel good about themselves by making positive and healthy change. It helps alleviate the self-hate component of depression.

Gretchen @

Thanks for sharing. Since I wrote that article another study has been released that sheds light on the researcher's decision to include a minimal amount of red meat in the antidepressant diet. This study found that a strictly vegetarian diet was associated with depression; though it didn't identify true causation there are other studies backing that point up and basic science data suggesting some of the vitamins and minerals from red meat play a role in depression:

http://www.sciencedirect.com/science/article/pii/S0165032716323916

Chris @

And people with a history of eating disorders should avoid it too, obviously.

But the second study from Hussin that you posted looks really promising. Thanks for posting that. I'm not surprised it's not that great for ADHD because the first few weeks you try it, it's pretty distracting.

I can tell you from six weeks experience in weekly 24 hr water IF that it's terrific in improving general mood and health in nondepressed aging men. Aside from the occasional hunger pangs (which pass), everything else feels great. Basically its a safe and free way to fight back andropause by naturally increasing HGH and its a medical detox that actually works.

James @

Thank you - that's a great video link. Intermittent fasting, and the related "ketogenic diet" have basic-science evidence supporting their benefits in brain function, memory, depression, and bipolar. Relevant articles include:

https://www.ncbi.nlm.nih.gov/pubmed/28373848
https://www.ncbi.nlm.nih.gov/pubmed/24097021
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4579557

There are risks and benefits with fasting. People who have type-1 diabetes, cardiac arrhythmias, renal disease, or who are pregnant should avoid it. A good summary of the risks and benefits is here:

http://www.webmd.com/diet/features/is_fasting_healthy#4

The risks of a high-calorie, Western diet seem to be greater. Hopefully the potential antidepressant effects of intermittent fasting will be tested, just as the Mediterranean diet was; it definitely has potential.

-Chris Aiken, MD

Chris @

As a caregiver of a patient with issues ranging from Bipolar I to Schizophrenia I feel I can honestly say that specific changes in the diet protected her brain from the damaging effects of the drugs that she was prescribed. I also feel that the diet (we used Paleo which is similar to Mediterranean), along with a specific supplement regimen, played an important part in recovery. We have had ZERO relapses or hospitalizations for over a year now. I do not understand why the psychiatric world is not eager to jump on this information and include it in their treatment programs immediately because even if it has minimal effects on the disease it has great all around health benefits.

Laura @

Thanks for sharing - I'm glad to hear those dietary efforts paid off -Chris Aiken, MD

Chris @

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