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Nutrient Deficiencies & Their Link To Depression

I usually select gut health and gut health related topics for this blog, but in an effort to expand the topics I discuss, this week, I want to talk about the connection between what we eat (food) and how we feel (mood).

As someone who has personally dealt with her own fair share of anxiety and mood related struggles over the years I absolutely can attest to, and appreciate the impact of lifestyle (nutrition and diet, stress management, sleep and leisure) on mental health.

This doesn’t just include mood disorders like depression and anxiety or seasonal affective disorder (SAD) by the way.

There’s no shortage of research on the role and impact of nutrition on other psychiatric illness like schizophrenia, bipolar disease and more.

As a health coach, I work with a lot of women many who are dealing with depression and anxiety. One strategy I use to help them is by way of their diet.

Despite it being backed by research, many psychiatrists fail to appreciate the role of nutrition in mental health, including the connection between nutrition and depression.

In my opinion, no amount of medication can make up for a poor diet. At the very least, before using common pharmaceutical ‘mood stabilizers’ such as Celexa, Cymbalta, Wellbutrin, there should be an examination of your intake of vitamins, minerals, essential fats & antioxidants.

Whether you’re using talk therapy, medication, or both to manage your depression, you’ll get more for your efforts if you also address your physical health, specifically the health of your brain as it relates to the foods you eat.

In this blog I’ll discuss how food impacts mood and neurotransmitter production and share nine nutrient deficiencies that have been linked to depression.

Food And Mood

Depression, anxiety and other mood disorders are thought to be directly related to imbalances with neurotransmitters.

A neurotransmitter is a chemical transmitter. They are messengers, carrying, boosting and balancing signals between neurons and target cells throughout the body.

Billions of neurotransmitter molecules work constantly to keep our brains functioning, managing everything from our breathing to our heartbeat.

They allow for learning, memory formation and the regulation of emotion. They can also affect a variety of psychological functions such as fear, mood, pleasure, and joy.

Some of the more common neurotransmitters that regulate mood are Serotonin, Dopamine, and Norepinephrine. Serotonin imbalance is one of the most common contributors to mood problems (and most of the serotonin produced in your body - literally almost all of it- COMES FROM THE GUT!)

The building blocks of neurotransmitters are amino acids like valine, leucine, isoleucine, and phenylalanine which come from the digestion and breakdown of dietary protein.

However the critical players in the synthesis and function of neurotransmitters are vitamins & minerals.

Think of neurotransmitter production like a factory beltline. It needs a certain number of employees to show up for maximum output/production.

If half the staff call in sick or don’t show up to work then production suffers.

Likewise for neurotransmitter production and function; you need optimal amounts of nutrients “showing up to work“ on a daily basis.

If they are lacking in the diet, mood can be disrupted. This can set the stage for the development of depression and anxiety.

Poor nutrition can also aggravate and worsen any existing mood and/or psychiatric disorder.

By improving your diet and using targeted supplements as needed, you can improve your brain health while supporting your mood at the same time.

The following are nine nutrients to focus on when it comes to using nutrition for depression support.

Omega-3 fats

Omega 3 fats are literally brain food. They are so powerful they can help prevent or delay Alzheimer’s disease, dementia and other forms of cognitive decline.

The DHA omega-3 fat in particular is critical for brain cell [neuron] structure.

Of the total amount of omega 3 fats in the brain, 92% of it is DHA omega 3.

Studies have compared "traditional" diets, like the Mediterranean diet to a typical "Western" diet and have shown that the risk of depression is 25% to 35% lower in those who eat a traditional diet.

Scientists account for this difference because the Mediterranean diet is high in vegetables, fruits, unprocessed grains, and sources of Omega 3 fats such as olives, olive oil and wild salmon.

Omega 3 EPA helps support mental health and depression in a couple of ways.

First, EPA supports neuron function and reduces blood viscosity. When blood flows freely, your brain cells get the oxygen and nutrients they need better.

Omega 3 EPA also acts like tricyclic antidepressants by modulating ‘calcium-ion’ flux.

EPA also helps to reduce inflammation. which is why research supports the role of omega-3 fats in improving symptoms of depression.

Inflammation is now seen both as a risk factor for, and having an aggravating effect on depression. (here and here)

This is also seen through diet.

For example trans fats, which are pro inflammatory have been shown to increase the risk for depression and poor cognitive function. (here and here)

While not fully understood in its role in mental health, EPA’s and DHA’s ‘sibling’, DPA omega 3 is another important nutrient.

It also helps to lower inflammation and when consumed along with EPA and DHA, DPA increases the uptake of all three by your body’s cells and tissues.

Great food sources of omega 3 fats are wild caught fish and seafood, especially fatty fish like salmon, omega-3 fortified eggs and supplements.

Also be sure to consider your omega 6 to omega 3 ratio. You don’t want to over consume omega 6 at the expense of omega 3.


Iodine plays a central role in mental health.

Low selenium and iodine levels have been found to contribute to the development of anxiety and depression, independent of thyroid functions. And in this study selenium and iodine replacement was useful for the prevention of anxiety and depression.

Iodine is critical for a healthy thyroid. the thyroid is the “master of metabolism“ (i.e. cellular fitness). Because iodine is crucial for a healthy and happy thyroid, and therefore T4 and T3 production and function, this mineral has a big role in good mental health.

Iodine helps ensure that there’s enough T4 and T3 in the brain to help it activate key neurotransmitters like dopamine, norepinepherine, serotonin, GABA, and acetylcholine.

Without out enough T4 and T3, you may experience insomnia, fatigue, difficulty concentrating and depression.

The decline in our soil quality means iodine has unfortunately been largely removed from our food supply. We used to get about 800 mcg per day through food but now most of us are lucky to get between 138 to 350 mcg per day.

While this intake is sufficient to stave off an overt deficiency, it likely won’t be enough to move people into the functional range where physiological processes are optimal including mental health.

Good food sources of iodine include seaweed, cod, iodized salt. Other moderate food sources include milk, yogurt, and eggs.

Good quality supplements should provide the RDA of 150 mcg per dose as a foundation.


Zinc is powerful. It is involved in over 250 separate biochemical pathways, or reactions. These reactions support just about every function needed for overall health, not the least of which is a strong immune system and mental well-being.

Zinc is also critical for neurotransmitter production and function. (here, here, here)

A review of the role of 3 minerals, zinc, selenium, and magnesium were looked at for their role in depression. Findings support the importance of adequate consumption of micronutrients in the promotion of mental health.

Unlike calcium, phosphorus and magnesium which is stored in your body in large amounts, zinc isn’t. You need a steady and reliable source every single day.

Its also worth mentioning that vegetarians and vegans who may consume large amounts of legumes and grains may need as much as 50% MORE zinc than the recommended amounts. This is because legumes and grains have anti nutrient compounds that can keep zinc from being fully absorbed by the body.

The best food sources include oysters, crab, beef, lamb, pork, dark meat, and chicken. Other decent food sources are legumes, cashews and a good quality multivitamin/multi mineral will have some as well.


Like zinc, magnesium is a powerhouse. It is required for over 300 separate biochemical pathways, or reactions. It is required for healthy teeth, reducing anxiety, regulating muscle and nerve function, blood sugar levels, and blood pressure and making protein, bone, and DNA

Most of us only get about half of the recommended amount: 420 mg per for men and 320 mg for women.

It’s estimated that about 75% of the US population falls short of their RDA.

There are several reasons for this including our intake of mostly refined foods, decreased soil levels, and medications that interfere with magnesium absorption.

Certain health issues can place you at risk for magnesium deficiency as well such as prediabetes or insulin resistance, diabetes, moderate to heavy alcohol consumption, and anyone with gastrointestinal disorders or digestive problems which can decrease absorption.

Magnesium is required to activate the enzymes needed for serotonin, dopamine and norepinepherine production. Also, whereas calcium and glutamate are excitatory in the neuron, magnesium is an ‘antagonist’ to them. Magnesium in this sense is calming and helps

with mood stability and balance.

If there’s not enough magnesium in the brain cells and synapses, they won’t work as well and this can lead to depression.

Good food sources include nuts & seeds, dark green vegetables, avocado, fish, blackstrap molasses, lima beans, whole grains, bran and dark chocolate. Pumpkin seeds are also a standout – they contain a lot of magnesium.

Supplements are typically needed to help people meet their minimum daily requirement on a consistent basis. By increasing magnesium intake, supplements can offer much needed support to people with depression so their brain and neurons can function optimally.

Vitamin D

Anyone who knows me knows that vitamin D is my baby and I feel strongly that most people don’t get nearly enough of it through their diet.

This is especially true depending on where you live, and how much exposure to the sun you get.

The rule of thumb is that the UVB index needs to be 3 or higher and the sun needs to be high enough in the sky. The easiest way to know if it is, is if your shadow is shorter than you are tall.

The brain thrives on vitamin D and a deficiency has not only been linked to depression, but anxiety, SAD, and dementia as well.

Vitamin D is also needed by your amygdala, the part of the brain that regulates emotion.

Supplementation is the only viable option to raise vitamin D levels to where they need to be for optimal, overall health and to lower the risk for depression.

Most people can maintain levels to prevent vitamin D deficiency and vitamin D deficiency symptoms such as rickets and osteomalacia. During the spring and summer a deficiency can often be avoided with some casual safe sun exposure. But food alone will not prevent low levels during the late fall and winter.

The best food sources of vitamin D are fatty fish like sardines, salmon, mackerel, and herring, trout, organic milk and eggs.


Like iodine, selenium is needed for healthy thyroid function.

Often, just increasing selenium intake can improve early symptoms of low thyroid function. A healthy thyroid supports mental health including reducing the risk for depression.

Selenium is also needed to convert the inactive thyroid hormone T4 to the active form T3. This conversion primarily occurs in the liver, the rest occurs in the gut and then in other tissues throughout the body.

When people are put on thyroid hormone replacement medication, it’s only T4. It’s assumed that people are able fully convert the medication form of T4 to T3 efficiently.

Sadly this isn’t always the case which is why many people who are put on Synthroid or Levothyroxine don’t feel better. Their depression remains or gets worse despite their ‘thyroid’ blood work being normal, e.g. lower TSH.

Ensuring you’re getting enough selenium is a good first step when it comes to managing and/or reducing your risk for depression.

Selenium is also needed to make your body’s master antioxidant and detoxifying compound glutathione. Glutathione is actually the major brain antioxidant.

Increasing glutathione has been shown to improve depression because glutathione reduces inflammation in the brain.

Glutathione is also needed to protect the thyroid gland. As it makes thyroid hormone, it produces a lot of hydrogen peroxide and glutathione protects against this.

Good food sources are Brazil nuts (two

a day is all you need!) nuts, sunflower seeds, fish, oysters, ham, shrimp, liver and chicken.


Iron deficiency is more common in women than men due to losses via menstruation.

The most common form of anemia is iron deficiency anemia. It’s symptoms are similar to depression: fatigue, irritability, apathy, brain fog, lack of motivation and appetite.

Having anemia-related symptoms such as these can lead to depression given the way in which they impact quality of life. While anemia itself may not be the cause for depression, a lack of consideration to iron intake could result in a misdiagnosis.

Anxiety is another consequence that can stem from having low iron levels. If you have low iron levels, it can trigger feelings of panic and lead to a panic attack. Increased anxiety can also lead to depression, or vice versa as these two often go hand-in-hand.

Eating vitamin C-rich foods along with iron-rich foods is a helpful way to increase the absorption of iron.

Good food sources are beef, pork, lamb, dark meat chicken, eggs, liver, oysters and white beans.


B complex vitamins typically include about 11 B vitamins all of which are involved in neurotransmitter production and function. B vitamins have many nervous systems benifits.

Some, like B12 are needed to help maintain brain mass, a.k.a. prevent brain shrinkage, a cause of dementia.

A classic B12 deficiency symptom is depression.

What’s very interesting is the fact that deficiencies in all of the B vitamins have a psychiatric component.

Mood disorders, psychoses, depression, anxiety, memory issues, cognitive function are all negatively impacted by vitamin B deficiencies.

Other important B vitamins for mental health include B1, B6, B3, and folate.

Folate, along with B12 and B6 help to lower levels of homocysteine, a by-product of protein metabolism. Elevated levels of homocysteine increase the risk for depression because homocysteine drives inflammation. Inflammation is now recognized as a risk factor for depression. In fact, most of the mood stabilizers (aka ‘antidepressants’) work for the very fact that they lower inflammation in the brain.

This is a great read on the food/mood connection, with information on B vitamins and depression.

Folate is another superstar B vitamin that works with vitamin B12 and B6 to support mental health. In order for dietary folate to be effective though, it needs to be converted to its active form 5-MTHR.

However about 66% of the population don’t do this effectively because they have a mutation in the gene 5-MTHF reductase.

This gene should turn on an enzyme (protein) whose job is to convert folate into 5-MTHF. For folks with this mutation, it puts them at a 180% increased risk for folate deficiency or a least a functional deficiency – meaning their folate and cellular machinery isn’t functionally optimally.

We can’t store B vitamins in our body like we can vitamins A, D E & K. We need a steady supply of they daily to satisfy all our our body’s requirements for them.

Some good food sources are whole grains, nuts & seeds, dark green vegetables, legumes, eggs, fish, liver and meat.

Vitamin C

The technical term for severely low Vitamin C levels is “scurvy.” Symptoms include bruising, bleeding gums, weakness, fatigue, and rashes.

But you don’t have to have scurvy to have functional vitamin C deficiency. Functional

Vitamin C deficiency is the term used to describe an intake that is high enough to prevent an overt clinical deficiency but not sufficient enough to allow you to function or feel your best.

One of the more common symptoms of functional vitamin C deficiency is depression.

Like your white blood cells and adrenal glands, your brain is a huge consumer of vitamin C. This vitamin helps to lower inflammation in the brain. This not only helps prevent oxidation- or rusting- of your neurons, but also lowers the risk for depression.

Vitamin C deficiency is relatively rare in developed countries but still affects more than 1 in 20 people.

Since humans cannot make vitamin C or store it in large amounts, it has to be consumed regularly (and absorbed!) to prevent deficiency, ideally through fresh fruits and vegetables. The need for vitamin C is increased by fever, inflammation, diarrhea, smoking, hyperthyroidism, iron deficiency, cold or heat stress, surgery, burns, and protein deficiency.

Good food sources include citrus, broccoli, kohlarbi, guava, papaya, lychee, pineapple, tomato, tomato juice, kiwi, bell peppers and strawberries.

The Bottom line

  1. Food feeds the brain. As an organ that accounts for 25% of our metabolic demands, the brain is in need of constant nourishment that can’t be met with poor dietary choices and an inadequate nutrient intake.

  2. Having optimal mental health cannot be realized if the underlying biology of mood regulation (the structure and function of the brain) isn’t addressed. This is where very building blocks of vitamins, minerals and essential fats come into play.

  3. No amount of pharmaceutical intervention and prescription medication can make up for a lack of nutrients.

  4. If you are struggling with depressive symptoms or depression then consider nutrient testing. Pinpointing and addressing nutrient deficiencies can go a long way in improving your mood and alleviating depression.

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