There’s a lot of anecdotal evidence which claims that you can ease or even cure depression with different foods. Let’s take a look whether there is any scientific merit to these claims.
The main points are summarized at the end of the post, as always.
First, let me define depression. Contrary to the common perception of some people, major depressive disorder is a mental disorder which involves dysfunctional brain biochemistry, but more on that later. Its main characteristics are low mood, low self-esteem, a loss of interest and pleasure for activities that would usually entertain you, and over-thinking your own problems. These are only some of the symptoms. You can check up the official criteria for depression here.
I’d like to point out that people often use the word depression in a very misguided way. Saying that you feel depressed, which often characterizes when you’re in a bad mood, feel down, or something similar, is not the same as being diagnosed with major depressive disorder. That would be like mixing up getting a tan and 2nd degree burns due to sun exposure.
An episode of depression usually last for several weeks, or longer, and affects all the major aspects of your life. If you feel that some of the symptoms which I’ve listed above describe you as well, then consult with your doctor and get a psychiatrist or psychologist to do an official diagnosis. A self-diagnosis is not an official diagnosis.
Currently, depression is best understood under a so-called biopsychosocial model. This model proposes that depression has biological, psychological, and social causes that work in an interactive fashion:
- The biological cause is a dysfunctional brain biochemistry, together with a specific genetic make-up. This genetic make-up makes you more vulnerable to stress from your environment.
- The psychological cause is a mixture of specific thinking patterns, a certain personality type, low self-esteem, and negative emotionality.
- The social cause is not as clear, there are many factors that can influence this. Poverty and social isolation can be examples of some social factors that can create triggers for depression to manifest itself in people.
SSRIs (selective serotonin re-uptake inhibitors) are a class of compounds which form the basis of how the majority of today’s prescribed antidepressants work.
Nowadays, the most commonly prescribed way of managing this disorder involves antidepressant medication (SSRIs) and psychotherapy sessions; cognitive behavioral therapy is used most commonly.
Cognitive behavioral therapy (CBT) is a form of psychotherapy with a strong evidence-based background. It is widely used for a number of mental disorders.
However, psychotherapy can be expensive, and some people actively choose not to use antidepressants due to their side-effects. With all that said, here’s where nutrition kicks in. People fail to realize that nutrition has an important role in mental health, and obviously depression as well.
Short disclaimer: If you think you suffer from depression and do not have it diagnosed, then please go to a mental health professional, they can offer you the best help. I am also not proposing that you can completely cure or prevent depression simply due to a healthy diet. While there is available anecdotal evidence where people have cured their episode of depression and never had a relapse due lifestyle changes which involved a healthy diet like the paleo, and weight training together with running, I cannot claim that you can stop depression based solely on the mentioned changes. They certainly give strong protection against it, however, studies have yet to assess that on a bigger scale.
With that said, let me start on the different foods which can partially prevent and help with depressive symptoms.
Food preference and carbs
The first important thing to know about depression is that it changes our preference for food. People with depression suffer from poor appetite, meal skipping, as well as an intense desire for sweet food. 
A neurotransmitter is a chemical which transmits signals from one brain cell to another. The variety of effects, which are a consequence of a neurotransmitter dysfunction, are many.
The latter is connected to the dysfunctional brain biochemistry I’ve mentioned earlier. Serotonin is a neurotransmitter which can lead to an overall insensitivity to future consequences of our behavior if there’s not enough of it available. This in return triggers risky, impulsive, and aggressive behavior which can lead to suicide; this is important because low levels of serotonin are connected to suicide . And as you might have guessed it, one of the main characteristics of people with depression are low levels of available serotonin. That is why SSRIs focus on improving serotonin levels.
Tryptophan is an essential amino acid, meaning our body doesn’t produce it, so we have to get it through our diet. It is required for the production of serotonin.
That is also the reason eating adequate amounts of carbs is important. Eating a meal rich in carbs triggers the release of insulin, especially if it has a high glycemic index. Insulin helps your blood sugar go into cells where it can be used for energy, it also simultaneously triggers the entry of tryptophan to your brain. It is possible that a diet low in carbs can accelerate depression because the mentioned cycle doesn’t get activated enough. And that is also the reason people with depression crave sweet food. It instantly improves their symptoms due to an increased insulin response . However, this has obvious long-term health consequences and is not advised. Food that has a low GI (vegetables, some fruit, whole grain pasta/bread, brown rice) is better for them because it provides a smaller insulin response which lasts longer and provides them with energy longer. Therefore, the amount of tryptophan that gets produced is stretched over a longer period and is more stable.
You might be thinking now:
“Well, if tryptophan is so important, let’s just food with a lot of tryptophan”.
Sadly it doesn’t work that way. This is one of three myths I’d like to debunk: 
- Eating foods high in tryptophan will not increase tryptophan or serotonin levels in our brain
- Bananas do not improve mood
- High protein foods (turkey) will not increase tryptophan or serotonin levels in our brain
If you’re unfamiliar with any of these myths, then even better, you were spared some widespread nonsense.
Omega-3 fatty acids
The connection between a deficiency in omega-3 fatty acids and mental illnesses is well known. Omega-3 fatty acid supplementation improves depressive symptoms . Based on current research, a dose of around 2 g of EPA has been shown to stimulate mood. Higher doses, up to 10 g of EPA, have been used in studies with depression and other mental illnesses without any side efects.
Omega-3 fatty acids are extremely important for our brain in general, they are one of the main compounds that create its membranes. Moreover, a diet lacking in omega-3 fatty acids leads to many disturbances in your brain functioning . It can make your brain “age faster” because it cannot renew its membranes as efficiently as it could if you would eat enough omega-3 fatty acids.
Vitamin B12 is one of the water-soluble vitamins with a very important role for your brain, your nervous system, as well as the formation of blood. It’s found in most animal-derived foods such as fish, meat; liver especially, poultry, eggs etc.
Folate is one of the naturally occurring forms of vitamin B. It can be found in a variety of foods such as spinach, liver, asparagus, and brussels sprouts. Folic acid, however, is produced synthetically. You can find it in fortified foods and supplements.
There’s not too much say here, supplementing with vitamin B, folic acid is advisable and an inexpensive way of improving depressive symptoms. Supplementing with 0.8 g of folic acid or 0.4 mg of vitamin B12 per day, depending on your deficiency, improves depressive symptoms. [6, 7]
Patients with depression tend to have lower folate levels. On average, their levels are 25% lower than those of healthy people. Moreover, low folate levels seem to make the usual antidepressants less effective. In one study, people with depression were supplemented with 0.5 mg of folic acid which improved the effectiveness of their antidepressants . Zinc supplementation increases the effectiveness of antidepressants as well. 
Some case studies report that a magnesium supplementation between 125 and 300 mg with each meal and at bedtime improves depressive symptoms in as fast as 7 days . However, we shouldn’t be putting too much faith in case studies. In any case, magnesium rich foods are: spinach, pumpkin seeds, avocados, mackerel, brown rice, bananas, various fried fruit, and others.
You can expect improvements in your depressive symptoms by supplementing with the following:
- Eating a diet with low GI (glycemic index) carbs (whole grain pasta and bread, brown rice, vegetables, some fruit), is better than eating food with a high GI due to a different effect on brain’s neurotransmitters.
- Adding an omega-3 fatty acid source, a pure supplement is probably better because the required amount of fish would be rather high for the average budget, improves depressive symptoms. In general, any type of fish that is eaten on a regular basis will be fine.
- Supplementing with vitamin B12 or folate improves depressive symptoms as well. 0.8 g of folate or 0.4 mg of vitamin b12 is an amount that has been shown to be effective. Vitamin b12 can be found in animal-derived foods, meat; especially liver, poultry, eggs, and fish.
- Folic acid and zinc improve the effectiveness of common antidepressants which are being prescribed. Folic acid can be found in fortified foods, zinc can be found in seafood, lamb, spinach, pumpkin seeds, cashews, and others.
- Some preliminary evidence from case studies shows that a supplementation between 125 and 300 mg of magnesium with each meal and at bedtime can drastically improve depressive symptoms.