Posted on: July 29, 2016 at 1:20 pm
Last updated: December 22, 2017 at 2:41 pm

This amazing article was written by Dr. Hilary Booth, licensed and registered Naturopathic Doctor. I encourage you to check out her website!


Mental health conditions are some of the most commonly diagnosed conditions in North America. According to the National Institute of Mental Health, 6.7% of all U.S. adults suffer from major depressive disorder1, and 18.1% suffer from anxiety2. Dementia affects about 5.3 million Americans, and that number is expected to double by the year 2050 due to the aging population3. The staggering prevalence of mental illness leads us to pose two questions: why are we seeing it at such high rates, and what can we do about it? The answer, at least in part, lies in the gut.

The Gut-Brain Connection

An emerging body of research has started to examine the relationship between the gut and mental health. This so-called “gut-brain connection” is garnering attention from world-class research facilities, including Johns Hopkins, where they have started calling the gut our “second brain”4. This second brain is home to more than 100 million nerve cells, the production of neurotransmitters like serotonin and dopamine, as well as a microbiome of bacteria that can communicate with our brain to affect our mood5.


Although the exact link between our first and second brains is not yet fully understood, we do know that if the second brain is functioning poorly, such as in irritable bowel syndrome (IBS), our mood and cognitive abilities become profoundly affected. Inflammation in the gut, an altered gut microbiome, and a compromised immune system are some of the mechanisms by which digestive issues can affect our mental health.

The second important way that our gut affects our mental health is by digesting and absorbing the nutrient building blocks that our bodies need to maintain a healthy nervous system. This is why our diets play a huge role in affecting how we feel, and how the Brain Diet can help us to prevent and reverse depression, anxiety, and dementia.

Mood, Depression and Neurotransmitters


Serotonin is one of the primary neurotransmitters with a role in anxiety and depression. It is the hormone that most anti-depressant and anti-anxiety medications seek to increase in the body in order to improve our mood. It is estimated that 90% of the body’s serotonin is made in the gut, not to mention that the building blocks for 100% of the body’s serotonin come from what we eat.


Serotonin is made from a protein called tryptophan, and also requires vitamin B6 (pyridoxine) and iron to be synthesized. Individuals who eat a low protein diet, or who are B6 or iron deficient, have lower levels of serotonin in their bodies and are more prone to anxiety and depression. We also see a reduction in the amount of serotonin produced and the speed at which it’s metabolized is increased in people diagnosed with dementia6.

Dopamine is another neurotransmitter that plays a role in mental health, and that requires adequate building blocks from our diet to be produced. Dopamine is the hormone that is responsible for feelings of reward, so it is an important aspect of mental health and addiction. Dopamine is also the neurotransmitter that shows the largest decline in the aging population and is thought to play a major role in dementia.

Similarly to serotonin, dopamine is also made from protein. It can be produced from either phenylalanine or tyrosine proteins, and requires both iron and vitamin B6 to be synthesized.

Brain Composition

Essential fatty acids are also an important aspect of our diets for improving mental health. The brain is almost 60% fat7, so it makes sense that we need to eat healthy fats in order for the brain to optimally perform.

Omega-3 fatty acids are the most important types of fats for brain development, of which eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are most important for brain health. Omega-3 fatty acids are known as essential fatty acids, meaning we cannot make them in the body, so we need to get them from food.

DHA is important for fetal and infant brain growth, and we also see a decline in DHA in the brain as we age. Supplementation with DHA in infants has been shown to improve mental and psychomotor development scores8 and DHA supplementation in fish oil is linked to improved cognitive scores and a decreased risk of dementia in the aging population8. EPA is anti-inflammatory and is important for mood and cognitive function. It has been found to be effective for the treatment of primary depression at the correct dosage and ratio to DHA in a robust meta-analysis study9.

The brain is also made up of about 73% water10, and mild dehydration can cause the brain’s volume to shrink. Dehydration can lead to poor mental function and symptoms of dementia11. It has also been shown that even mild dehydration can also cause increased tension, anxiety, fatigue in otherwise healthy people12.

The Brain Diet

Based on what we’ve learned about our neurotransmitters and brain composition, there are some important aspects of our diet that need to be included to promote good mental health and cognition. In some instances, depression, anxiety, and cognitive decline are precipitated by a poor diet and can be significantly improved by following these guidelines.

1. Protein

Protein is the most basic building block of the many neurotransmitters, including serotonin and dopamine, that are important for mental health. You can calculate your daily protein requirement using the formula: 0.8 * #kg of body weight = the total number of grams of protein per day (don’t forget to convert your weight from pounds into kilograms by dividing by 2.2). For example, a 160-pound person should eat about 60g of protein each day.

Healthy sources of protein: grass fed organic meat and poultry, wild organic and sustainable fish, beans, chickpeas, lentils, hemp hearts, nuts, and seeds.

2. Fats

Healthy fats are essential to brain composition. About 35% of your diet should come from fats. Healthy fats include polyunsaturated fatty acids like omega 3’s and moderate amounts of healthy saturated fats. Trans unsaturated fatty acids (trans fats) from processed foods should always be avoided.

Healthy sources of fats: avocado, coconut oil, fatty fish like salmon, mackerel and sardines, flax seeds, flax oil, chia, nuts, and seeds.

3. Micronutrients

the brain diet, brain food

Micronutrients include our B-vitamins and iron, as well as other vitamins and minerals that help our brain function well. Anxiety and low mood can be caused by deficiencies in many micronutrients, and keep in mind that this may be due to either a poor diet or lack of ability to absorb and utilize nutrients. Lab testing is a great way to identify nutrient deficiencies that may be contributing to mental health concerns.

Healthy sources of iron: grass fed organic meat and poultry, wild organic and sustainable fish, beans, dark leafy greens (spinach), raisins, apricots, molasses, fortified grains

Healthy sources of vitamin B6: organ meat (liver, kidney), grass fed organic meat and poultry, wild organic and sustainable fish, chickpeas, soy, pistachios, banana

Healthy sources of other micronutrients: a variety of brightly colored fruits and vegetables (dark leafy greens, beets, peppers, etc.), nuts, and seeds.

4. Water

Water is important for keeping our brains (and the rest of our bodies) hydrated. It is also important for our detoxification pathways by clearing toxins from the bloodstream that can affect our mood and cognitive function.

There is no exact amount of water that’s right for everyone. The general rule is 2.1L per day for women and 3.4L per day for men. However, you should never feel like you’re force-feeding yourself water. If you forget to keep hydrated, try setting a reminder on your phone or computer at work to remind you to take a few sips every hour. Keep in mind that lemon water, carbonated water, and herbal teas also count as water intake but caffeinated beverages, juice, and soda do not.

5. Foods to Avoid

the brain diet, brain food

Certain foods negatively impact the gut environment, thereby affecting our mood. Inflammatory foods, such as foods containing sugar and preservatives should be avoided. Focus on fresh foods rather than processed/packaged foods; if you can read the ingredients on the label, you can eat it. Avoiding extra sugars helps to stabilize our mood by balancing our blood sugar and reducing inflammation. Focus on natural sugars from honey, maple syrup, and raw organic coconut sugar instead of high fructose corn syrup and cane sugar.

You may also consider avoiding other inflammatory foods such as dairy, gluten, eggs, and nightshade vegetables. These foods have been shown to trigger irritable bowel symptoms, which have been linked with precipitating or worsening anxiety, depression, and cognitive decline by negatively impacting the gut-brain relationship.

Always speak with your healthcare professional before dramatically changing your diet to ensure you are well-supported and making safe changes.


Dr. Hilary Booth
Naturopathic Doctor
Contributor to The Hearty Soul.

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