🚨 If you are thinking about harming yourself, or feel unable to keep yourself safe, please get help now rather than reading on. In the US, call or text 988, or call 911 if you are in immediate danger. Elsewhere, contact your local emergency number or a crisis line, or go to your nearest emergency department. If you can, tell someone you trust today. This page is nutrition education. It is not a crisis service, and it is not treatment. Nothing here should delay you contacting a doctor.

⚠️ Medication safety: please read first. The nutrition and supplement approaches on this page are meant to work alongside your prescribed treatment, never to replace it. Never stop, reduce or change your antidepressant medication without your prescriber's guidance. Doing so can be dangerous. Several supplements interact with antidepressant medication, so talk to your prescriber or pharmacist before starting anything on this page.

Definition

What Is Depression?

Persistent low mood or loss of interest, lasting at least two weeks and present most of the day, together with changes in sleep, appetite, energy, concentration and how a person sees themselves. It is diagnosed clinically, not by any blood test.

It is not sadness, and it is not a failure of effort or character. Sadness has a cause and lifts. Depression frequently has no proportionate cause, does not lift on its own schedule, and takes with it the very capacities (energy, motivation and hope) that would be needed to climb out of it. That is why telling someone to eat better is not only unhelpful but can add to the burden.

Nutrition genuinely appears in this picture, though further from the center than most articles suggest. Some dietary patterns are weakly associated with lower depression risk¹, and one randomized trial found a dietary intervention improved symptoms². Set against that, the large trials testing whether supplements prevent depression have been negative.

💡 Key Insight: The association between poor diet and depression runs in both directions. Depression reduces appetite, energy and the capacity to shop and cook, so poor diet is partly a consequence. Any honest account has to say that observational studies cannot separate the two.

💊 What the supplement trials found

Long-term vitamin D3 did not reduce the risk of depression or clinically relevant depressive symptoms in more than 18,000 adults³. Supplements have not prevented depression in the large trials.

🚫 What is not true

That depression is caused by a food, cured by removing one or fixed by a supplement. No dietary change has been shown to replace treatment, and the claim that it can is the most harmful idea in this whole area.

⚠️ Some things that look like depression are not. An underactive thyroid, anemia, obstructive sleep apnea, vitamin B12 deficiency and the effects of alcohol can all produce fatigue, low mood and poor concentration. These are worth excluding rather than assuming, because each has its own treatment. See thyroid disorders, iron-deficiency anemia and sleep apnea.

Signs & Symptoms

Symptoms of Depression

It does not always look like sadness. In many people it looks like exhaustion, irritability or simply nothing at all.

Symptom	What happens
Persistent low mood	Most of the day, most days, for at least two weeks. Worth knowing: Duration and persistence are what separate it from ordinary low periods.
Loss of interest or pleasure	Things that used to matter stop mattering. Worth knowing: Often the more telling symptom, and frequently present without obvious sadness.
Appetite and weight change	Either direction; loss of appetite or eating for comfort. Worth knowing: This is where nutrition and depression meet most directly, and why a nutrition page exists at all.
Sleep disturbance	Early waking, difficulty falling asleep or sleeping far more than usual. Worth knowing: See insomnia, and consider sleep apnea where daytime sleepiness dominates.
Fatigue and slowed movement	Everything takes more effort than it should. Worth knowing: Easily attributed to overwork, and easily missed.
Difficulty concentrating or deciding	Reading, working and choosing all become harder. Worth knowing: Frequently mistaken for a memory problem, particularly in older adults.
Worthlessness or excessive guilt	A harsh and distorted view of oneself. Worth knowing: The distortion is a symptom, not an accurate assessment.
Thoughts of death or self-harm	From feeling life is not worth living to specific plans. Worth knowing: If you have plans or feel unable to stay safe, call or text 988, or call 911 if you are in immediate danger. Otherwise tell a doctor today. See the warning at the top of this page.

⚠️ If low mood has ever alternated with periods of unusually high energy, reduced need for sleep or uncharacteristic decisions, say so before any treatment starts. That pattern points to bipolar disorder rather than depression, and it changes treatment substantially, because antidepressants given alone in bipolar disorder can trigger a manic episode. See the bipolar disorder guide.

Causes

Causes of Depression

Depression has no single cause: genetic, biological, environmental and psychological factors all play a part⁶, and some medical problems produce the same symptoms, which is why they are checked first.

Cause	How It Contributes to Depression	What Helps
Family history and biology	Research points to genetic and biological factors acting together with environmental and psychological ones⁶	Treatment, not self-blame: psychological treatments are the first treatments, with medicine added in moderate and severe depression⁴
Stressful and painful life events	Abuse, severe losses, unemployment, bereavement and trauma make depression more likely, and depression can in turn add to the stress⁴	Talk therapy, and staying connected with people you trust⁶
Physical illness and some medicines	Depression often occurs with diabetes, cancer, heart disease and chronic pain, each making the other worse. Some medicines also have side effects that add to depression symptoms⁶	Treatment for the illness, and a medication review with your prescriber; never stop a prescribed medicine on your own
Conditions that imitate it	Thyroid disorders, viruses and some medicines can cause the same symptoms, so a clinician rules them out with an examination, an interview and lab tests⁶	The blood tests in the diagnosis section; correcting a deficiency treats the deficiency, not the depression
Alcohol and drugs	Harmful use of alcohol is among the factors that influence depression, and alcohol and illicit drugs can make it worse⁴	Cutting down on alcohol, as the diet section sets out
Pregnancy, birth and menopause	Pregnancy, the postpartum period, the menstrual cycle and menopause bring changes that can bring on an episode in some people⁶	Seeking care when symptoms appear, rather than waiting for them to pass⁴
Diet and sleep	Links run both ways: across prospective studies most diets show no clear link and the Mediterranean pattern only a weak one¹, while insomnia more than doubles the odds of later depression⁷	Regular meals and a Mediterranean-style pattern, tested alongside treatment in one small trial²; insomnia treated in its own right

Diagnosis

How Depression Is Diagnosed

There is no blood test for depression. The blood tests exist to find the things that imitate it.

Test	What it shows
Clinical assessment and symptom questionnaires	The diagnosis itself, severity and risk. Worth knowing: Questionnaires screen and track; they do not diagnose on their own.
Thyroid function	An underactive thyroid, which imitates depression closely and is treatable. Worth knowing: See thyroid disorders.
Complete blood count and ferritin	Anemia, a common and correctable cause of fatigue. Worth knowing: See iron-deficiency anemia.
Vitamin B12 and folate	Deficiencies that affect mood and cognition, more common with age, vegan diets and some medicines. Worth knowing: Correcting a deficiency helps that deficiency; it is not a depression treatment.
25-⁠OH-D (vitamin D)	Whether deficiency is present, checked where it is suspected. Worth knowing: Correct it as a deficiency, not as a mood treatment. Supplementation did not reduce depression risk in a large trial³.
Sleep history, and apnea screening where indicated	A treatable cause of daytime exhaustion and low mood. Worth knowing: Rarely asked about unless someone raises it.
Alcohol and substance history	Both a cause and a consequence, and it changes what will work. Worth knowing: Needs asking without judgment, or it is not answered honestly.
Medication review	Several common medicines list low mood as a recognized effect. Worth knowing: A prescriber conversation, never a reason to stop something on your own.

💡 Tell your clinician about every supplement you take. This matters more here than on almost any other page on this site, because several supplements marketed for mood interact with antidepressants. The supplement section below explains why.

Treatment Comparison

Conventional and Holistic Treatment for Depression

🌿 HOLISTIC

💊 CONVENTIONAL

🌿

Holistic / Functional Approach

Diet quality, sleep, activity, alcohol and correcting what is deficient. Alongside treatment, never instead of it

Best Dietary Evidence

The SMILES trial found greater improvement in depression scores with dietary support than with social support over 12 weeks²

Association

A Mediterranean-style diet is weakly associated with fewer self-reported symptoms across prospective cohorts¹, though cause runs both ways

Timeline

12 weeks in the one trial that showed benefit, as an addition to treatment rather than a first step

Limitation, stated plainly

No dietary or supplement intervention has been shown to replace treatment for major depression

Full Holistic Approach Includes

A Mediterranean-style dietary pattern, the one tested in the trial that showed benefit.
Regular eating, which matters more when appetite has gone. Something simple and repeated beats an ambitious plan that does not happen.
Reducing alcohol, which worsens mood and sleep and interacts with treatment.
Sleep, treated in its own right; see insomnia.
Physical activity, which has reasonable evidence and does not require enthusiasm to start.
Correcting documented deficiencies (B12, folate, iron, vitamin D) because they are deficiencies.
Not doing this alone. The clearest finding in this field is that treatment works and that isolation makes everything worse.

🌿 Worth knowing: depression removes the energy and motivation that these changes require, which is not a personal failing but a symptom. Start with one small thing, and treat difficulty as evidence for getting help, not against it.

Nutritional Strategy

Diet for Depression

One trial worth taking seriously, one association worth understanding and a great deal of overstatement to discount.

The one depression diet trial worth taking seriously

💡 The trial that made this a serious question. SMILES randomized adults with major depression and a poor baseline diet to either dietary support toward a modified Mediterranean pattern or to a social support control, alongside whatever treatment they were already receiving. The dietary group showed greater improvement in depression scores at 12 weeks². The limitations matter and are usually omitted: it was small, participants could not be blinded to which group they were in, and it tested dietary change added to existing care rather than instead of it. Later work found dietary interventions affected some symptom profiles more than others⁹.

What to eat or do	Details
Mediterranean-style pattern	Evidence: The tested one. Practical note: Vegetables, legumes, fruit, whole grains, fish, olive oil, nuts. This is what SMILES actually asked people to do.
Eating regularly at all	Evidence: Practical rather than trialed. Practical note: When appetite has gone, consistency beats quality. Simple repeated meals are a legitimate goal.
Reducing alcohol	Evidence: Consistent. Practical note: Worsens mood and sleep, interacts with medication and is easy to increase without noticing.
Fatty fish twice a week	Evidence: No clear link with depression in a 2025 review, apart from postpartum depression¹. Practical note: Food first. See the supplement section for why the capsule is rated lower.
Reducing ultra-processed foods	Evidence: Associated. Practical note: Part of what better diet quality means in the cohort studies¹.
Caffeine, if sleep is disturbed	Evidence: Indirect. Practical note: Does not cause depression, but it fragments sleep; poor sleep worsens mood.
Restrictive or elimination diets	Evidence: Not supported, and risky here. Practical note: They narrow intake, add pressure and can worsen an already difficult relationship with eating.

⚠️ If eating has become a source of distress in itself, that needs care in its own right. Depression and disordered eating frequently occur together, and advice designed for one can worsen the other. If food, weight or your body has become a source of anxiety, or eating feels out of control, please tell your doctor. Treat the advice on this page as something to discuss with them rather than to follow alone.

Supplement Protocol

Evidence-Based Supplements for Depression

The interactions on this page are more important than the benefits.

🚨 St. John's wort is the most important safety item on this page, and it is sold without a prescription in most countries. Taken with an SSRI or other serotonergic antidepressant it can cause serotonin syndrome, which is potentially life-threatening. It is also a powerful inducer of drug metabolism, which means it can reduce the effectiveness of oral contraceptives, anticoagulants, immunosuppressants, some HIV and cancer medicines, and more¹⁰. Do not take it alongside an antidepressant, and tell your prescriber and pharmacist before taking it at all. Anyone with any history of mania must not take it; see the bipolar disorder guide.

Supplement	What it is for	Typical range	Timing	Notes & cautions
Vitamin B12 and folate	Correcting a documented deficiency, which can itself cause low mood, fatigue and poor concentration. Not a treatment for depression in people who are replete.	Test first; dose set with your clinician	As advised	Do not supplement folate without checking B12 first, because folate can mask B12 deficiency while nerve damage continues. More likely to be relevant with age, a vegan diet, metformin use or malabsorption.
Omega-⁠3 (EPA and DHA)	Modest and inconsistent evidence as an addition to treatment. Food first, fatty fish twice weekly.	Agree on any supplement dose with your clinician	With a fat-containing meal	Trials are mixed and heterogeneous, and a trial of omega-⁠3 for preventing depression was unsupportive⁸. Tell your clinician if you take an anticoagulant or antiplatelet, and before planned surgery. In heart trials, fish oil supplements raised the risk of atrial fibrillation, an irregular heartbeat, more so above 1 g a day¹¹, so check any fish oil supplement with your clinician first.
Vitamin D3	Correcting a deficiency. Not a mood treatment.	Set a daily dose with your clinician; most adults need no blood test first	With a fat-containing meal	In more than 18,000 adults, long-term supplementation did not reduce depression risk or improve mood scores³. Correct a deficiency because it is a deficiency. Avoid large intermittent doses; see osteoporosis. The upper intake level is 4,000 IU a day for adults and children 9 and over, and 1,000 to 3,000 IU a day for younger children depending on age; agree on a child's dose with their clinician.
St. John's wort	Listed here only so that the risks are stated, not as a recommendation.	Not recommended on this page	n/a	See the warning above. Serotonin syndrome with serotonergic antidepressants, and it reduces blood levels of a long list of medicines including oral contraceptives¹⁰. Never combine it with an antidepressant, and never start it without telling your prescriber.

🚨 What to avoid, specifically. Any product promising to replace an antidepressant, or to cure depression. Stopping prescribed treatment to try a supplement, which is the most dangerous single action associated with this topic. St. John's wort alongside an antidepressant. 5-⁠HTP and SAM-e taken with serotonergic medicines, for the same serotonin syndrome reason. Kratom and other unregulated mood products. And be wary of anyone who tells you depression is caused by a single food or nutrient, because the evidence for that does not exist.

💡 Where the real leverage is. Getting treatment, and staying on it long enough to work. Sleep, alcohol, regular meals, some movement and other people. Nutrition supports all of that, and it is the support rather than the treatment.

What to Expect

What to Expect Over Time

Most people with depression benefit from treatment, and improvement usually comes gradually⁶.

Treatment and supportive care, together

First Weeks

Get assessed, including the tests that rule out look-alikes. Psychological treatment comes first, with medicine added for moderate or severe depression⁴. An antidepressant usually takes 4 to 8 weeks; sleep, appetite and concentration often improve before mood⁶.

Months 1 to 3

Treatment is reviewed, and finding the right one can take trial and error⁶. The diet trial ran for 12 weeks alongside existing treatment, not instead of it².

Months 3 to 12

Antidepressants are usually continued for at least 6 months after symptoms improve. Never stop one suddenly or without your doctor: withdrawal symptoms are common, and the dose is reduced gradually¹².

Long Term

Some people have more than one episode⁴. If two antidepressants have not helped, options include adding a different type of medicine or brain stimulation therapy⁶.

When to Seek Care

If you have thoughts of suicide or self-harm, call or text 988 in the US, or chat at 988lifeline.org; call 911 or emergency services if you are in immediate danger⁶. Tell your prescriber at once about new or worse suicidal thoughts after starting or changing an antidepressant, especially under age 25 ⁶, and about any past periods of unusually high energy before treatment starts⁴.

📬

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References & Evidence Notes

Each numbered entry below is either a source you can follow or a note setting out what the evidence does and does not support. Both are numbered together so the markers in the text line up.

Last reviewed October 20, 2026. Supplement entries are cross-checked against the NIH National Center for Complementary and Integrative Health and the Linus Pauling Institute Micronutrient Information Center.¹³ This page is nutrition education, not medical advice, and it does not replace your doctor. Nutrition does not treat depression. Depression is a medical condition with effective treatments, and no dietary change or supplement on this page has been shown to replace them. Nothing here is a reason to decline, delay or stop treatment. What nutrition education can do is help you understand the evidence well enough to have a better conversation with the clinician who does treat you.

Diet quality and depression risk: a systematic review and meta-analysis of prospective studies. J Affect Disord. 2025. PubMed 40158860. Across 92 prospective cohorts and 21 trials, a Mediterranean-style diet was weakly associated with fewer self-reported symptoms, most dietary patterns showed no association, prevention trials showed none, and the authors rated the overall evidence very low. In the cohort studies reverse causation is a serious concern here, because depression itself reduces appetite, energy and the capacity to shop and cook. See also the Mediterranean diet review, PubMed 38219230. ↩
Jacka FN, et al. A randomised controlled trial of dietary improvement for adults with major depression (the SMILES trial). BMC Med. 2017;15(1):23. PubMed 28137247. Dietary support produced greater improvement in depression scores than social support over 12 weeks. Limitations that matter: a small sample, participants could not be blinded to their allocation, and the intervention was added to existing treatment rather than compared against it. ↩
Okereke OI, et al. Effect of long-term vitamin D3 supplementation vs placebo on risk of depression or clinically relevant depressive symptoms and on change in mood scores. JAMA. 2020;324(5):471-⁠480. PubMed 32749491. More than 18,000 adults, median follow-up over five years; no significant difference in depression risk or mood scores. The participants were not selected for vitamin D deficiency, so this argues against supplementing replete people rather than against correcting deficiency. ↩ ↩ ↩ ↩
On how common depression is and what comes first: the World Health Organization estimates that 5.2% of adults worldwide have depression, about 322 million people, that it is about 1.5 times more common in women, and that more than 10% of women who are pregnant or have just given birth experience it. People who have lived through abuse, severe losses or other stressful events are more likely to develop it, and harmful use of alcohol is among the factors that influence it. Psychological treatments are the first treatments, combined with antidepressant medicines in moderate and severe depression, and a person in immediate danger of harming themselves should contact emergency services or a crisis line, WHO, depression. ↩
On US figures: in 2021 an estimated 21.0 million US adults, 8.3%, had at least one major depressive episode in the past year, 10.3% of women and 6.2% of men, NIMH, major depression statistics. ↩
On causes, treatment and safety: the US National Institute of Mental Health states that genetic, biological, environmental and psychological factors play a role; that depression often occurs with diabetes, cancer, heart disease and chronic pain, that some medicines contribute to symptoms, and that thyroid disorders, viruses and medicines can mimic it, so a clinician rules these out; that psychotherapy is often tried first for milder depression; that antidepressants usually take 4 to 8 weeks to work, with sleep, appetite and concentration often improving before mood; that people under 25 may have more suicidal thoughts in the first weeks of an antidepressant or after a dose change; and that anyone having thoughts of suicide can call or text 988, or call 911 in a life-threatening situation, NIMH, depression. ↩
On insomnia and depression: a meta-analysis of 21 longitudinal studies found that insomnia predicted later depression, with an overall odds ratio of 2.60, about two and a half times the odds of people without sleep difficulties, PubMed 21300408. ↩
Effects of vitamin D3 and marine omega-⁠3 fatty acids supplementation on indicated and selective prevention of depression. J Clin Psychiatry. 2023;84(4). PubMed 37378490. Further evidence against supplementation for the prevention of depression. ↩
Effects of dietary interventions on depressive symptom profiles: results from the MooDFOOD depression prevention study. Psychol Med. 2022;52(14):3247-⁠3256. PubMed 33823960. Dietary intervention effects differed across symptom profiles rather than acting uniformly, which is a reason to be specific about what is being claimed. ↩
Advantages and disadvantages of using St. John's wort as a treatment for depression. Cureus. 2022;14(9):e29468. PubMed 36299970. Reviews the interaction profile, including serotonin syndrome with serotonergic antidepressants and induction of drug metabolism reducing the effectiveness of many other medicines. ↩
Gencer B, Djousse L, Al-Ramady OT, Cook NR, Manson JE, Albert CM. Effect of long-term marine omega-⁠3 fatty acids supplementation on the risk of atrial fibrillation in randomized controlled trials of cardiovascular outcomes: a systematic review and meta-analysis. Circulation. 2021;144(25):1981-⁠1990. PubMed 34612056. Seven trials with 81,210 people followed for about 5 years: omega-⁠3 supplements were linked to a higher risk of atrial fibrillation (hazard ratio 1.25), more so in trials of more than 1 g a day (1.49), and the risk rose with each additional gram. ↩
On stopping antidepressants: NHS guidance says antidepressants are usually continued for at least 6 months after symptoms improve, that they should not be stopped suddenly or without talking to a doctor, and that the dose is reduced gradually, usually over several weeks or months, because most people get some withdrawal symptoms, which can feel like the illness returning, NHS, stopping antidepressants. ↩
National Center for Complementary and Integrative Health (NIH), nccih.nih.gov, and the Linus Pauling Institute Micronutrient Information Center, lpi.oregonstate.edu/mic. ↩

Depression

What Is Depression?

💊 What the supplement trials found

🚫 What is not true

Depression by the Numbers

Symptoms of Depression

Causes of Depression

How Depression Is Diagnosed

Conventional and Holistic Treatment for Depression

Holistic / Functional Approach

Full Holistic Approach Includes

Conventional / Medical Approach

Conventional Approach Includes

Diet for Depression

Evidence-Based Supplements for Depression

What to Expect Over Time

Treatment First, Nutrition Alongside

References & Evidence Notes

Depression

What Is Depression?

💊 What the supplement trials found

🚫 What is not true

Depression by the Numbers

Symptoms of Depression

Causes of Depression

How Depression Is Diagnosed

Conventional and Holistic Treatment for Depression

Holistic / Functional Approach

Full Holistic Approach Includes

Conventional / Medical Approach

Conventional Approach Includes

Diet for Depression

Evidence-Based Supplements for Depression

What to Expect Over Time

Related Conditions

Treatment First, Nutrition Alongside

References & Evidence Notes