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The Nutritional Approach to Depression

Depressed person sitting by the wall

I want to start this post with a disclaimer: in no way am I touting that nutrition is the be all, end all for coping with mental health challenges, including depression. I am a registered nurse and holistic nutritionist, and I understand there is a big psychological component when it comes to depression, anxiety, and other mental health disorders. However, my clinical background and education has also taught me that nutrition is paramount to optimal health, and that includes mental health. My take-away message from this post is that a well-balanced, nutrient-rich diet is essential for a well-balanced mood. Keep reading to learn why and how you can optimize yours.


Depression can be classified into several categories, but clinical depression and major depressive disorder are the most common ones. It is characterized by protracted feelings of sadness and hopelessness that can affect one’s sleeping and eating habits; and it contributes to loss of interest or motivation to engage in daily activities, social engagements, work life, and activities that one previously enjoyed. Other symptoms can include changes in weight, fatigue or loss of energy, problems with concentration, irritable mood, feelings of guilt or worthlessness, and suicidal thoughts.

(If you think you might be depressed, please consult with a trained healthcare professional. The PHQ-9 is a tool that health care providers use to screen for depression. It can be a good indicator of clinical depression. Click here to check it out.)

Depressed person sitting by the wall

With increasing media coverage on mental health, society is becoming more aware of how it can impact daily lives. Awareness is growing, and while stigma is decreasing, I think we still have a long way to go. However, let’s have a look at some statistics. Chances are, you or someone you are close to has been affected by depression or another mental health disorder.

  1. 1 in 5 Canadians will personally experience a mental health problems or illness in any given year [1].
  2. About 81% of adults will experiences major depression at some point in their lives [1].
  3. More than 50% of people who have had an episode of major depression will experience a recurrence [2].
  4. By age 40, about 50% of the Canadian population will have or have had a mental illness [1].
  5. 1 in 8 adults identified symptoms that met the criteria for a mood disorder at some point during their lifetime [2].
  6. Depression is now recognized as the leading cause of illness in the United States for the age 15-44 [2]. (There are no statistics for Canada on this, but I would hazard a guess that the results are similar.) .
  7. As of 2017, 8.6% of Canadians age 12 years or older reported that they have a mood disorder [5].
  8. As of 2017, 20% of adults in the United States have been diagnosed with depression [4].
  9. One third of claimants for private long-term disability benefit programs in Canada have psychiatric or mental health disabilities [3].

What does this information tell us? A lot. It tells us that mental health disorders and depression are prevalent in our society; and these conditions are not only affecting adults, but they are also affecting our youth.

It is true that today we live in a society that values high productivity and high connectivity (but this is through technology and does not necessarily equate to a supportive or meaningful network). Many people feel that this high stress “go-go-go” mentality with less supportive meaningful interactions is creating a generation of individuals who are more impacted by depression, anxiety, and the like. I definitely agree with this. But is it not also true that because of this high-paced environment we live in, our diet has suffered? People are eating more fast-food, more processed food, and using more stimulants (such as coffee) to keep up with this fast-paced lifestyle, and they are consuming fewer whole, natural foods. (And don’t get me started on where our food comes from, how it is grown, and the means in which it is transported – this all impacts its nutrient content too – but I’ll save that for a future post.)

Let’s dive into how nutrition affects our mental health, specifically in relation to depression. (Although many of the same concepts can be applied to other mental health disorders.)

Depressed person sitting by the wall


On a biological level, our body creates chemicals that are responsible for regulating a healthy mood. These chemicals are called neurotransmitters and hormones, and they act to transmit messages to different parts of our body. Neurotransmitters send messages between the cells in our nervous system and brain, and hormones send messages to all other body cells. Some hormones are also neurotransmitters, but not all neurotransmitters are hormones.

There are several of these chemicals that are responsible for mood regulation:

  1. Serotonin – Responsible for feelings of alertness and happiness; also regulates sleep.
  2. Dopamine – Responsible for feelings of alertness and happiness; also regulates sleep.
  3. Norepinephrine – Responsible for feelings of alertness and happiness; also regulates sleep.
  4. Glutamate – Responsible for feelings of alertness and happiness; also regulates sleep.
  5. GABA (gamma-amino butyric acid) – Responsible for feelings of alertness and happiness; also regulates sleep.

*Some research shows that decreased glutamate and GABA may be associated with clinical depression, while high glutamate and low GABA can lead to anxiety and other neurodegenerative disorders [8].

If you are wondering what these chemicals have to do with nutrition, the answer is straight forward. Our neurotransmitters and hormonal messengers are made from amino acids (proteins), fatty acids (healthy fats, ideally), and cholesterol; and in order for them to be synthesized from these compounds, certain vitamins and minerals need to be present to make that change happen. Therefore, we need obtain these building blocks and vitamin/mineral catalysts in our diet and from the foods that we eat (and supplementation, in some cases) if we want to be able to produce them.

Have a look at this flow chart to gain a better understanding of where some of your neurotransmitters and hormones come from.

Depressed person sitting by the wall

There is another concept called biochemical individuality, and it is also an important one to remember when it comes to nutrition. What works for one person may not work for another. While we all have the same biological processes, because of environmental and genetic influences, one person may require more dopamine, for example, to achieve optimal mood balance while another may require more vitamin B12. This is why it can be so important to work with a qualified healthcare professional when attempting to find your optimal balance for health and wellness.


As I said earlier, eating a well-balanced, whole foods diet is paramount to achieving optimal mental well-being. However, depending on a person’s biochemical individuality, a deficiency in any single nutrient can alter brain chemistry and lead to low mood, depression, anxiety, or other mental health disorders. There are a few specific nutrients that have been shown to have a more significant impact on our mood if they are missing or deficient from our diet. Let’s have a closer look at these.


This is the amino acid precursor for your body to make serotonin (as well as melatonin which is important for sleep). Many people do not get enough tryptophan in their diet which can result in depletion of serotonin levels, leading to mood imbalances. Foods that are rich in tryptophan include fish, turkey, chicken, cheese, beans, tofu, nuts/seeds, oats, and eggs.

Tryptophan can also be difficult for your body to access as a nutrient. In the bloodstream, it must compete with other amino acids (from the protein you eat) to get into the brain where it can have an effect. However, consuming tryptophan-rich foods with carbohydrates can increase its bioavailability. This is because carbohydrates cause an increase in insulin levels, and insulin helps to shuttle tryptophan into the brain where it can have an impact on serotonin levels.


This is another important amino acid. We can either get tyrosine from our foods, or the body can make it from another amino acid called phenylalanine. Either way, it is the precursor for your body to make dopamine (which is then also made into noradrenaline and adrenaline). As discussed earlier, these neurotransmitter hormones can affect mood in a number of ways.

Omega-3 Essential Fatty Acids (EFAs)

EFAs are called “essential” for a reason: we need to get them from external sources (either food or supplements) because our body is unable to synthesize them. Omega-3 deficiencies, specifically EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) which come from fish oils, have been linked to depression; and studies have found that countries with high rates of fish oil consumption have low rates of depressive disorders.

There are several reasons omega-3s may have a significant impact on depression:

  1. The human brain is composed primarily of fat, and proper nerve signaling is dependent on healthy cell membranes. Studies have shown that the physical properties (re: health) of brain cell membranes has a direct influence on the synthesis of neurotransmitters, the signals they transmit, reuptake (re: ability to recycle and re-use) of serotonin and other neurotransmitters, and neurotransmitter binding to cells. [9]
  2. Omega-3 fats help build receptor sites for serotonin which increases the amount of serotonin produced.

An easier way of looking at it is this: an omega-3 deficiency is the equivalent of having a home with a rotating door – anything that comes along can get in, and depending on what it is, this can have serious consequences for your home, including theft and vandalism, and the long-term psychological effects of a home invasion. However, eating a diet rich in omega-3s and supplementing with fish oils is the equivalent of hiring a bad-ass Vin Diesel-type doorman to monitor the entrance of your home and make sure only essential VIPs are let in, the “trash” gets taken out, and any important messages are conveyed to you in an effective way.

B Vitamins

It is important to understand that B vitamins work synergistically (re: each one is needed for all the others to work effectively). If you are depleted in one, you are often depleted in others. B vitamins not only help with digestion and metabolism of the foods we eat, but they are essential co-factors in the synthesis of different neurotransmitters and hormones. (See previous neurotransmitter chart as an example.) Specifically, vitamins B6, B12, and folate help to maintain balance of the brain’s neurotransmitters and therefore balance mood. However, deficiencies in the other B vitamins can also lead to depression, anxiety, restlessness, problems with memory and cognition, and irritability.

Other Minerals

There are several other minerals that play important roles as co-factors or catalysts when it comes to synthesizing hormones or neurotransmitters, or delivering their messages. These include, but are not limited to, zinc, chromium, magnesium, and iron.

As you can probably appreciate from the above information, there may be, but there is not necessarily one single contributing factor when it comes to nutritional deficiencies and the role they play in depression. This is why it is so important to eat a well-rounded, whole foods diet: to make sure you are getting the nutrients you need to support you in optimal mental health.

Depressed person sitting by the wall


Talking about how nutrient deficiencies can contribute to depression, it would logically make sense that a nutrient-deficient diet can do the same. While more people are becoming aware of the effects our food has on our health, there are still many in the dark on this subject; and therefore, still many who eat the Standard American Diet (appropriately coined “S.A.D.”). Unfortunately, this type of highly processed, high sugar, high fat diet not only starves our body of the nutrients it needs, but the breakdown and metabolism of these types of foods uses up the very nutrients that we are needing to support our mental health – especially the B vitamins, zinc, and chromium. By eating SAD-ly, people are, in effect, digging themselves into an even deeper hole.

Blood sugar fluctuations can also impact mood, and several studies have shown hypoglycemia (re: low blood sugar) to be present in depressed individuals. Hypoglycemia is often associated with individuals who consume a lot of refined or simple carbohydrates. When we eat simple carbohydrates, they are absorbed rapidly into our bloodstream (compared with complex carbohydrates which are released more slowly). This rapid onset of blood sugar causes a surge of insulin from our pancreas to help shuttle the sugar into our cells. But if this happens too quickly (as is often the case for those who eat meals that are heavy with refined carbohydrates), we get a rebound drop in our blood sugar which can leave us feeling irritable and having difficulty with concentration, among other things. Not only that, but the rebound drop in blood sugar stimulates our adrenal glands to secrete cortisol and adrenaline which also contribute to mood instability. If one has these types of blood sugar fluctuations regularly, you can appreciate how this can contribute to poor mood over time.

Stay hydrated. Water is essential to life, and our body uses it to carry out accumulated waste. This relates to our mental health because if we are dehydrated, our body will use tryptophan and tyrosine to eliminate the waste instead. Since these amino acids are the building blocks for many of our mood stabilizing neurotransmitters and hormones, their depletion can lead to depression.

It’s not food-related, but I also want to take a moment to acknowledge the importance of managing stress levels, getting enough exercise, and light exposure in relation to depression. While this article’s focus is on nutrition, all of these things play just as important a role in regulating the feel-good chemicals in our body.

Depressed person sitting by the wall


I want to be clear that I am not a doctor. But I am a nurse, and I am familiar with many of the pharmaceuticals prescribed to patients on an annual basis for depression. Often, writing a script seems like a simple answer from the doctor’s perspective (and the patient’s). In some cases, it may be warranted, and I don’t want to make anyone feel ashamed of needing to use a prescription medication in order to manage their depression. However, that being said, prescription medications do not get to the root cause of your illness. And once started, many people have a difficult time coming off of anti-depressants.

Even if your depression is related to a chemical imbalance, unless you are providing your body with the building blocks or precursors to build those chemicals, even a medication isn’t going to fix the problem. It may offer a Band-Aid solution, but that’s about it. Let me explain…

Many prescription anti-depressants work on the basis of “chemical imbalances predispose an individual to depression and other mental health disorders”. (Obviously psychological factors play a role here, but we are talking strictly chemical treatment in this section.) Therefore, correcting these imbalances should lead to an improvement in mood. Most of the major players for anti-depressant drugs are designed to influence the balance and function of our neurotransmitters, most commonly serotonin and norepinephrine. These medications generally work by increasing the intrasynaptic amounts of serotonin and norepinephrine. This is where, in my opinion, the issue in treatment arises. Sure, increasing these amounts may have an impact on mood, but it is limited because these drugs don’t make these neurotransmitters; they simply make it easier for what is already present in the body to be viable for use. For a person who already has low serotonin or norepinephrine levels, this doesn’t do them much good. Their body still needs the tools to be able to make adequate amounts of these brain chemicals to begin with.

Make sense? It’s like developing an improved way of making apple pie; but if you don’t have enough apples to begin with, your new technique won’t have much of an impact on the number of apple pies that are being made. (Anyone else have pie on the brain!?)

This is why it is my strongly held belief that we need turn our attention to nutrition (and other lifestyle factors) as a means for achieving optimal mental health and well-being.

Depressed person sitting by the wall


If you’ve made it this far, I’ve talked to you about all the reasons nutrition is important for mental health, and you’re probably thinking: “Now what?”

Let’s recap (with a few extra tips).

1. Eat a well-balanced, whole food diet that includes:

  1. plenty of fruits and vegetables (excellent sources of all those vitamins and minerals)
  2. healthy proteins like chicken, turkey, fish, organic tofu, nuts, seeds, and eggs (for those amino acids)
  3. healthy fats from fish, nuts/seeds and their oils, and avocados (for omega-3s and other healthy fats)
  4. drink plenty of water and stay hydrated

2. Stabilize blood sugars by:

  1. eliminating refined carbohydrates
  2. including protein, fiber, and healthy fat with every meal (to slow release of carbohydrates into the blood)

3. Reduce or eliminate refined carbohydrates and sugars, and highly processed or fried food.

4. Supplementation:

  1. As I’ve mentioned, nutrition is not a one-size fits all model. While following the above steps can help, some people may need extra support through supplementation of specific nutrients, especially if depression is something they’ve been dealing with for a long time.
  2. What works for one person may not work for another. In order to save yourself time, money (spent on trying different products), and frustration, consider working with a qualified health care professional to help you target your deficiencies more efficiently.

As a registered nurse and holistic nutritionist, my role is not to treat disease but to promote health and wellness. My approach is about providing one’s body with the tools it needs to support its own optimal function. If you’ve been struggling with depression or any other mental health conditions, I strongly encourage you to consider the information I’ve shared with you in this post. Many people just need a gentle nudge in the right direction, but others may require more coaching.

Nutrition and helping people reach their optimum potential is my passion. If you would like some guidance, I am available for working with you one-on-one to help you take back the reigns on your mental health and your life. Please use the “Get in Touch” form on this website if you’d like some more information about nutrition coaching.

If you would like to do more reading on the topic of nutrition and mental health, I would highly recommend “Optimum Nutrition for the Mind” by Patrick Holford. It covers a variety of mental health diagnoses (including depression, anxiety, bipolar, and addictions) and what can be done to help them from a holistic viewpoint.


  9. Murray, M. & Pizzorno, J. “Encyclopedia of Natural Medicine”, 3rd edition.
  10. Holford, P. “Optimum Nutrition for the Mind”
Coralie Cardy

Published On: 12/16/2020

By Coralie Cardy