Short answer: Diet can help depression a little, alongside treatment, not instead of it. In the small SMILES trial, 32% of people on a Mediterranean-style diet reached remission, against 8% with social support. Large cohort studies link healthier diets to lower risk, but a big supplement prevention trial was null. Eat more vegetables, fish, legumes and whole grains, and less ultra-processed food.

Diet is not a substitute for the treatment your doctor prescribes. Do not stop or change antidepressants or other medication on the basis of anything here; discuss any change with your doctor or care team.

A healthier diet can modestly reduce depressive symptoms and is linked to a lower risk of developing depression. The evidence is moderate. A few small randomized trials show benefit when people with depression improve their diet, and large observational studies point the same way. But the trials are small and not all are positive. Food works best as one part of treatment, next to medication or therapy.

What to eat for depression

The diet tested in the trials is a Mediterranean-style pattern. You don’t need a rigid meal plan, and the same principles work in any food culture: Japanese, Indian, Mexican, West African or other traditional cuisines built on whole ingredients.

  • Vegetables and leafy greens (5+ servings a day): folate, magnesium, fiber and polyphenols. Spinach, kale, Swiss chard and rocket are especially nutrient-dense.
  • Fatty fish (2-3 servings a week): salmon, sardines, mackerel, anchovies and herring provide EPA and DHA. Canned sardines and mackerel are cheap and need no cooking; try our sardine avocado bowl.
  • Whole grains and legumes (daily): oats, brown rice, quinoa, lentils, chickpeas and beans give slow-release carbohydrates, fiber, B vitamins, zinc and magnesium.
  • Nuts and seeds (a handful daily): walnuts for plant omega-3, pumpkin seeds for zinc and magnesium, Brazil nuts for selenium.
  • Fermented foods (1-3 servings a day): yogurt, kefir, sauerkraut, kimchi and miso support gut bacteria. See fermented foods.
  • Extra-virgin olive oil as your main cooking and dressing fat.
  • Berries and colourful fruit (1-2 servings a day).
  • Eggs (several a week): affordable protein, choline, B12 and vitamin D.

And limit:

  • Ultra-processed food. If the ingredient list includes things you wouldn’t find in a home kitchen, it is ultra-processed.
  • Added sugar. Aim for below 25 grams a day, far less than the average Western intake.
  • Refined carbohydrates such as white bread, white pasta, pastries and sugary cereals.
  • Alcohol. If you drink, keep it modest. During treatment for depression, consider stopping altogether.
  • Industrial seed oils high in omega-6. The evidence is weaker here, but a high omega-6 to omega-3 ratio is associated with more inflammatory signaling.

How to start

  1. Fix one meal a day first. Eggs with greens and olive oil, or oats with berries, nuts and yogurt.
  2. Add fish twice a week. Sardines on toast, baked salmon or a mackerel salad.
  3. Swap one processed snack a day. Nuts for crisps, fruit and dark chocolate for biscuits, water or green tea for sugary drinks.
  4. Add before you remove. More vegetables naturally crowd out less nutritious food, without the strain of restriction.

The evidence: what the trials found

SMILES: diet as part of treatment

The SMILES trial (Jacka 2017) was the first randomized trial designed to test whether improving diet could treat clinical depression. It enrolled 67 adults with moderate-to-severe major depression. Most (55 of 67) were already in treatment with therapy, medication or both.

Participants got either seven sessions with a clinical dietitian over 12 weeks, following a modified Mediterranean diet, or “befriending” social support with the same number and length of visits. After 12 weeks, the diet group improved significantly more on a standard depression scale (MADRS). Remission was 32.3% in the diet group against 8.0% with social support.

The numbers behind those percentages were small: 10 people against 2. The number needed to treat was 4.1, meaning about one extra remission for every four people given diet support. The confidence interval was wide (2.3 to 27.8). Matching the visits reduces, but doesn’t rule out, the chance that attention alone explained the gain, and participants knew which group they were in. Cost modelling from 20 participants’ baseline diets estimated the recommended diet would cost less per week than what they had been eating.

HELFIMED: food hampers and cooking classes

The HELFIMED trial (Parletta 2019) randomized 152 Australian adults with self-reported depression. One group got a Mediterranean-style program (fortnightly food hampers and cooking workshops for three months, plus fish oil supplements for six months); the other joined a social group. After three months, the diet group had significantly larger drops in depression scores and better mental health quality of life. The benefits held at six months, though only 85 of the 152 completed that assessment. Because the diet group also took fish oil, the trial can’t separate diet from supplement.

MooDFOOD: a null prevention trial

Not every trial is positive. The MooDFOOD trial (Bot 2019) randomized 1,025 overweight adults across four European countries who had raised depressive symptoms but not clinical depression. They got a multi-nutrient supplement (omega-3s, folic acid, vitamin D, selenium and calcium), a food-related behavioral therapy, both, or neither.

Nothing reduced the onset of major depression over one year. The authors concluded the findings did not support either approach for prevention. MooDFOOD tested prevention rather than treatment, and mostly supplements rather than whole-diet change, so it doesn’t directly contradict SMILES. But its food-therapy arm was also null, a reminder that the positive trials are small.

Large cohort studies

  • SUN Project, Spain: Sanchez-Villegas 2009 followed 10,094 university graduates for a median of 4.4 years. People with higher Mediterranean diet adherence had a 26 to 51 percent lower rate of diagnosed depression than those with the lowest adherence.
  • SUN fast food analysis: Sanchez-Villegas 2012 followed 8,964 participants for a median of 6.2 years. The highest fifth of fast food eaters had a 36 percent higher rate of depression than the lowest fifth, with a significant trend across intake levels. Commercial baked goods showed no clear dose-response pattern.
  • Lassale 2019 meta-analysis: across 41 observational studies (20 longitudinal, 21 cross-sectional), the four longitudinal studies showed a 33 percent lower risk of depression with the highest Mediterranean diet adherence. Other healthy-diet scores showed similar links.

These are observational results and can’t show that diet caused the difference.

Pooled trials: a small effect

A 2019 meta-analysis of 16 randomized trials (Firth 2019) found that diet changes reduced depressive symptoms compared with control conditions. The pooled effect was small (g = 0.16), and 15 of the 16 trials were in people without clinical depression. The same analysis found no effect on anxiety.

How food might affect mood

These pathways are plausible, but none has been shown to explain the benefit seen in diet trials.

Inflammation. People with major depression tend to have higher levels of inflammatory markers such as CRP and IL-6. Inflammation may play a causal role in some people, though this is still being studied. One idea is that it diverts tryptophan, the building block of serotonin, toward a neurotoxin called quinolinic acid. The Mediterranean pattern is associated with lower inflammatory markers and ultra-processed food with higher ones. More in our guide to neuroinflammation and diet.

Gut bacteria. Most of the body’s serotonin is made in the gut. It doesn’t cross into the brain directly but affects it indirectly, through the vagus nerve, the immune system and tryptophan supply. A study of 1,054 people in the Flemish Gut Flora Project (Valles-Colomer 2019) looked at gut bacteria. Two types, Coprococcus and Dialister, were depleted in people with depression, even after allowing for antidepressant use. Coprococcus produces butyrate, a fatty acid that calms inflammation. The study is observational and can’t show whether these bacteria affect mood. Our gut-brain axis diet page covers this in more depth.

Building blocks for brain messengers. Serotonin is made from tryptophan, an amino acid found in turkey, eggs, cheese, nuts, seeds and legumes, with folate, vitamin B6 and iron as helpers. A meta-analysis of experiments (Ruhe 2007) looked at sharply lowering tryptophan with a special amino-acid drink. It lowered mood in people with a past or family history of depression, but not in healthy people without that history.

Nutrients studied for depression

Whole diets matter more than single nutrients, but several have been studied on their own.

Omega-3s (EPA)

A meta-analysis of 26 trials with 2,160 participants (Liao 2019) found that omega-3 supplements reduced depressive symptoms compared with placebo. The benefit was seen with formulations that were at least 60 percent EPA, at EPA doses of 1 g a day or less. DHA-dominant products showed no benefit. If you eat fatty fish two to three times a week, a supplement is likely unnecessary. If you are considering one, discuss it with your doctor or pharmacist first, especially if you take blood thinners.

Folate and B12

Pooling 11 mainly cross-sectional and case-control studies with 15,315 participants, Gilbody 2007 found that low folate status was associated with depression (adjusted odds ratio 1.42). These designs can’t show whether low folate causes depression.

L-methylfolate, the active form of folate, has been tested as an add-on to SSRI antidepressants in people who hadn’t responded well (Papakostas 2012). The first trial (148 patients, mainly 7.5 mg a day) found no difference from placebo. The second (75 patients, 15 mg a day) found a better response rate than placebo. At these doses it is a prescription product and should only be used under a doctor’s care.

Folate is found in dark leafy greens, legumes, asparagus and liver. Vitamin B12 comes mainly from meat, fish, eggs and dairy. See B vitamins and the brain.

Zinc

A meta-analysis (Swardfager 2013) found that blood zinc was significantly lower in people with depression than in controls, and the deficit was proportional to depression severity. Oysters are the richest source per serving; red meat, poultry, legumes, nuts and seeds also supply it.

Magnesium

Observational studies consistently link low magnesium intake to higher depression risk. A trial (Tarleton 2017) gave 126 adults with mild-to-moderate depression 248 mg of elemental magnesium a day for six weeks. It improved depression and anxiety scores, with changes within two weeks. The trial was open-label with no placebo, so expectation effects can’t be ruled out. Leafy greens, nuts, seeds, legumes and dark chocolate are good sources.

Vitamin D

Several meta-analyses link low vitamin D to higher depression risk. A 2020 meta-analysis of 25 trials (Cheng 2020) found that supplements reduced negative emotions, mainly in people with major depression or low vitamin D, but results varied widely. VITAL-DEP, the largest trial (Okereke 2020), included 18,353 adults aged 50 and over. Taking 2,000 IU a day for a median of 5.3 years did not reduce their risk of depression. Food sources are limited (fatty fish, egg yolks, fortified foods); sunlight is the main natural source.

Foods linked to higher depression risk

Ultra-processed food. The NutriNet-Santé cohort (Adjibade 2019) followed 26,730 French adults. Each 10 percent increase in the share of ultra-processed food in the diet was associated with a 21 percent higher rate of new depressive symptoms over about five years. This kind of study can’t prove cause.

Sugar. Over the long term, high sugar intake promotes insulin resistance and inflammation, both implicated in depression. In the Whitehall II cohort (Knuppel 2017), men were compared by sugar intake from sweet foods and drinks. Those in the highest third had 23 percent higher odds of a common mental disorder, such as anxiety or depression, after five years than those in the lowest third. Mood did not predict later changes in sugar intake, which argues against reverse causation, but the study is observational.

Alcohol. Alcohol is a central nervous system depressant. It disrupts sleep, depletes B vitamins and magnesium, and impairs serotonin function. The link runs both ways: heavy drinking raises depression risk, and depression raises the risk of heavy drinking.

Safety

  • Supplements can interact with medicines, including antidepressants. Ask a doctor or pharmacist before starting one, especially if you are pregnant, breastfeeding, taking medication or have a health condition. Use supplements only where a specific deficiency exists, with a healthcare provider.
  • Fish oil and omega-3 supplements can increase bleeding risk with anticoagulant or antiplatelet drugs. In trials, doses above about 1 g a day were linked to a higher risk of atrial fibrillation.
  • Magnesium: the upper limit from supplements is 350 mg a day for adults; higher doses can cause diarrhea. Take extra care with kidney disease.
  • Vitamin D: the adult upper limit is 4,000 IU a day. The Endocrine Society’s 2024 guideline advises against routine testing and high doses in healthy adults.
  • Antidepressants: keep working with your doctor, psychiatrist or psychologist. Do not stop or reduce an antidepressant without your doctor.

Frequently asked questions

Can diet alone cure depression?

No. Depression has genetic, psychological, social and biological causes. The evidence suggests diet may reduce symptoms alongside medication or therapy. In SMILES, which had the strongest results, most participants were also receiving other treatment.

How quickly can diet changes affect mood?

Steadier blood sugar and better sleep (from less caffeine and alcohol) may bring changes within days. In SMILES, the diet benefit was measured at 12 weeks.

Why do I crave sugar when I’m depressed?

Cravings are common during depression. One explanation is that carbohydrates trigger insulin, which clears competing amino acids from the blood so more tryptophan reaches the brain. The resulting spikes and crashes may worsen mood over time. Regular meals with protein and fat, tryptophan-rich foods, and berries or dark chocolate instead of refined sugar can help.

Sources

  • Adjibade, M., Julia, C., Alles, B., et al. (2019). Prospective association between ultra-processed food consumption and incident depressive symptoms in the French NutriNet-Sante cohort. BMC Medicine, 17(1), 78. doi:10.1186/s12916-019-1312-y
  • Bot, M., Brouwer, I. A., Roca, M., et al. (2019). 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, 321(9), 858-868. doi:10.1001/jama.2019.0556
  • Cheng, Y. C., Huang, Y. C., & Huang, W. L. (2020). The effect of vitamin D supplement on negative emotions: A systematic review and meta-analysis. Depression and Anxiety, 37(6), 549-564. doi:10.1002/da.23025
  • Firth, J., Marx, W., Dash, S., et al. (2019). The effects of dietary improvement on symptoms of depression and anxiety: a meta-analysis of randomized controlled trials. Psychosomatic Medicine, 81(3), 265-280. doi:10.1097/PSY.0000000000000673
  • Gilbody, S., Lightfoot, T., & Sheldon, T. (2007). Is low folate a risk factor for depression? A meta-analysis and exploration of heterogeneity. Journal of Epidemiology and Community Health, 61(7), 631-637. doi:10.1136/jech.2006.050385
  • Jacka, F. N., O’Neil, A., Opie, R., et al. (2017). A randomised controlled trial of dietary improvement for adults with major depression (the ‘SMILES’ trial). BMC Medicine, 15(1), 23. doi:10.1186/s12916-017-0791-y
  • Knuppel, A., Shipley, M. J., Llewellyn, C. H., & Brunner, E. J. (2017). Sugar intake from sweet food and beverages, common mental disorder and depression: prospective findings from the Whitehall II study. Scientific Reports, 7(1), 6287. doi:10.1038/s41598-017-05649-7
  • Lassale, C., Batty, G. D., Baghdadli, A., et al. (2019). Healthy dietary indices and risk of depressive outcomes: a systematic review and meta-analysis of observational studies. Molecular Psychiatry, 24(7), 965-986. doi:10.1038/s41380-018-0237-8
  • Liao, Y., Xie, B., Zhang, H., et al. (2019). Efficacy of omega-3 PUFAs in depression: a meta-analysis. Translational Psychiatry, 9(1), 190. doi:10.1038/s41398-019-0515-5
  • Okereke, O. I., Reynolds, C. F., Mischoulon, D., et al. (2020). Effect of long-term vitamin D3 supplementation vs placebo on risk of depression or clinically relevant depressive symptoms and on change in mood scores: A randomized clinical trial. JAMA, 324(5), 471-480. doi:10.1001/jama.2020.10224
  • Papakostas, G. I., Shelton, R. C., Zajecka, J. M., et al. (2012). L-methylfolate as adjunctive therapy for SSRI-resistant major depression: results of two randomized, double-blind, parallel-sequential trials. American Journal of Psychiatry, 169(12), 1267-1274. doi:10.1176/appi.ajp.2012.11071114
  • Parletta, N., Zarnowiecki, D., Cho, J., et al. (2019). A Mediterranean-style dietary intervention supplemented with fish oil improves diet quality and mental health in people with depression: A randomized controlled trial (HELFIMED). Nutritional Neuroscience, 22(7), 474-487. doi:10.1080/1028415X.2017.1411320
  • Ruhe, H. G., Mason, N. S., & Schene, A. H. (2007). Mood is indirectly related to serotonin, norepinephrine and dopamine levels in humans: a meta-analysis of monoamine depletion studies. Molecular Psychiatry, 12(4), 331-359. doi:10.1038/sj.mp.4001949
  • Sanchez-Villegas, A., Delgado-Rodriguez, M., Alonso, A., et al. (2009). Association of the Mediterranean dietary pattern with the incidence of depression: the Seguimiento Universidad de Navarra/University of Navarra follow-up (SUN) cohort. Archives of General Psychiatry, 66(10), 1090-1098. doi:10.1001/archgenpsychiatry.2009.129
  • Sanchez-Villegas, A., Toledo, E., de Irala, J., et al. (2012). Fast-food and commercial baked goods consumption and the risk of depression. Public Health Nutrition, 15(3), 424-432. doi:10.1017/S1368980011001856
  • Swardfager, W., Herrmann, N., Mazereeuw, G., et al. (2013). Zinc in depression: a meta-analysis. Biological Psychiatry, 74(12), 872-878. doi:10.1016/j.biopsych.2013.05.008
  • Tarleton, E. K., Littenberg, B., MacLean, C. D., Kennedy, A. G., & Daley, C. (2017). Role of magnesium supplementation in the treatment of depression: a randomized clinical trial. PLOS ONE, 12(6), e0180067. doi:10.1371/journal.pone.0180067
  • Valles-Colomer, M., Falony, G., Darzi, Y., et al. (2019). The neuroactive potential of the human gut microbiota in quality of life and depression. Nature Microbiology, 4(4), 623-632. doi:10.1038/s41564-018-0337-x