Nutritional psychiatry is a fancy term for an emerging field that seeks to address mental health issues through diet.
It emphasizes the link between nutrition and mental health and is typically used alongside behavioral and lifestyle interventions, talk therapy, and sometimes medications to improve mental health and reduce the risk of mood disorders.
In many cases, nutritional treatments have demonstrated equal to or better than results attained through medication alone. They also do not bring about unwanted side effects such as those caused by drug therapies.
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Cereals, Pizza, and Traditional Diet: Studies On Nutritional Psychiatry
A prominent figure in this field is Felice Jacka. Jacka is the director of the Food and Mood Center at Deakin University and president of the Society for Nutritional Psychiatry. She produced a PhD paper that compared the levels of anxiety and depression among women following a traditional diet (high in vegetables, fish, fruits, nuts, and whole grains) and those consuming a typical Western diet composed of fried foods, saturated fats, refined grains, and processed products.
The study involved 1,046 women between 20 and 93 years old. Jacka found that those following a traditional diet reported lower levels of depression and anxiety compared to those eating refined cereals for breakfasts, McDonald's for lunch, and pizza for dinner. These results demonstrate an association between the quality of one’s habitual diet and the high prevalence of mental health disorders and overall mood levels.
Other studies that have compared traditional diets, like the Mediterranean diet and the traditional Japanese diet, to a typical Western diet, have shown that the risk of depression is 25% to 35% lower in those who eat a traditional diet.
Research also supports the importance of nutrition in neurodegenerative diseases, particularly Alzheimer’s disease. In fact, neurologists now estimate that approximately 90% of Alzheimer’s disease is preventable by adopting a healthy diet and lifestyle.
Studies show that the risk for Alzheimer’s disease is more significant in people who consume high amounts of cholesterol, saturated fat, excess calories, and low amounts of fiber, vegetables, and fruits. Saturated fat and cholesterol can damage neurons and form beta-amyloid plaques, which impede blood flow to important parts of the brain. The toxic effect of cholesterol in its oxidized form also leads to inflammation which compromises brain function. Even the nitrates that are often added to processed meats as a preservative have been shown to increase the risk of dementia.
How Poor Nutrition Impacts Your Brain
Now did you know that while your brain makes up about 2% of your body weight, it uses between 20-25% of all the oxygen you inhale and calories you burn?
However, while your brain does play the star role in your mental and emotional experience, other organs are also key players, especially your endocrine system and digestive system. And like the brain, they also all require the right fuel in order to function at their best.
Researchers have suggested multiple possible mechanisms for how food can influence mood, including changes in the gut microbiome and chronic inflammation, oxidative stress, blood sugar spikes, nutritional deficiencies, and alterations in neurotransmitter levels.
1. Changes In The Gut Microbiome
Studies have shown that those with mental health conditions such as depression and anxiety often show a lack of diversity in the gut microbiome.
An imbalance in the microbiome can affect the production of neurotransmitters which are essentially chemicals that are released from nerve cells to other target cells to communicate information. They are like messengers, and too much or too little of any one neurotransmitter can change the way you think, feel, and behave. A large majority of these chemicals are produced by the bacteria in your gut, including 90% of your serotonin (your “happy hormone”) and about half of your dopamine (associated with feelings of reward).
An imbalance in your gut microbiome can also compromise your gut lining, allowing bacteria and their endotoxins, such as lipopolysaccharides, to enter your bloodstream, triggering an inflammatory response. This can also lead to inflammation in the brain which can further lead to the breakdown of the blood-brain barrier (BBB), and result in what is referred to as a leaky brain.
The BBB maintains brain nutrition, regulates the levels of neurotransmitters, limits blood macromolecules from leaking into the brain, and protects the brain against toxins, pathogens, inflammation, injury, and disease. A leaky BBB is thought to play a role in different neurological and psychiatric disorders, including brain fog, Alzheimer’s disease, vascular dementia, depression, schizophrenia, as well as other memory and mood disorders.
In a 2016 study, researchers transplanted feces from depressed people into rats which showed that gut microbiota may play a causal role in the development of features of depression. 34 patients with major depression and 33 matched healthy controls were recruited. A fecal microbiota transplantation was prepared from a subgroup of depressed people and controls and transferred to the microbiota-deficient rats. The researchers found that the rats who received the fecal transplant from the depressed people exhibited behaviors characteristic of depression. They also experienced alterations in tryptophan metabolism (tryptophan is the precursor to serotonin, your “happy hormone”).
2. Oxidative Stress
Oxidative stress occurs when there is an imbalance between unstable free radicals and detoxifying antioxidants in the body. The phenomenon has been linked with cancer, heart disease, and—you guessed it—depression and other neurological disorders. For example, both animal and human studies have shown that those with depression have elevated levels of oxidative stress compared to healthy controls.
Diet can influence oxidative stress with healthy diets associated with reduced markers of oxidative stress, and a Western diet linked with increased markers.
Reactive oxygen species (ROS) — which are often considered free radicals—are highly reactive molecules containing oxygen that are formed enzymatically, chemically, photochemically, and by irradiation of food. ROS are produced naturally by the body, but exposure to radiation, certain chemicals or food products (such as saturated fat found in animal products) can increase their levels.
ROS can alter the instructions coded in a strand of DNA or alter a cell’s membrane, changing the movement of what enters or leaves a cell. This damage can lead to cell death and has been linked to a number of diseases, including Alzheimer’s disease.
3. Neuroplasticity
Our brains are plastic, meaning they can change shape and structure in response to experiences throughout life. Emerging research suggests that dietary choices may be able to physically alter the size of the hippocampus, a brain region that is central to learning, memory and mood.
A study following 250 women aged 60 has shown that low intake of nutrient-dense foods and high adherence to the Western diet is associated with decreased volume in the left hippocampal lobe. Likewise, a longitudinal study looking at over 450 individuals also found that long-term healthy diet quality was associated with a larger total hippocampal volume.
One of the main drivers behind neuroplasticity is a protein called brain-derived neurotrophic factor (BDNF). BDNF plays a crucial role in the growth of nerve cells and has been seen to be at lower levels in individuals with depression. Polyphenols found in plant foods have been shown to increase BDNF concentrations. 
4. Blood Sugar Spikes
Blood sugar levels can have a tremendous impact on our moods. Studies confirm that poor blood sugar control is associated with depression, anxiety, irritability, nervousness, anger, sadness, and even poor sleep.
Depression currently affects about 25% of individuals with diabetes, a population more susceptible to pronounced blood sugar fluctuations.
However, blood sugar imbalances do not only affect diabetics. Otherwise healthy individuals consuming a diet high in refined carbohydrates and added sugars may experience a sudden spike in their blood sugar, followed by an exaggerated insulin response, leading to acute hypoglycemia.
A 2017 prospective study found positive associations between high sugar consumption and common mental health disorders, concluding that refined sugar intake has an adverse effect on long-term psychological health.
5. Nutritional Deficiencies
Patients struggling with their mental health are found to also be deficient in nutrients that can help regulate their moods and brain functions. Unfortunately, nutrition as a treatment protocol for mental health disorders is still in its early days and is yet to be part of formal training in this field.
However, there are already sufficient studies to back up the link between food and mood. These nutrient deficiencies can range from B Vitamins, omega-3s, zinc, magnesium, and many more—all of which could lead to symptoms like depression, anxiety, or poor concentration.
We’ve written a full guide on the 9 nutrient deficiencies linked to mental disordres in this article right here—plus, which foods and supplements you can take to help you fill these deficits.
The Link Between Food and Brain Health
The verdict is in: What you put on your plate can have a massive effect on your brain’s health and, therefore, your mood. If you’re living with mental health challenges, or you have a loved one who does, then you know how difficult it can be to live with. And you are not alone. It’s a constant struggle that so many people in the world endure.
But if you start eating foods that your brain will love, you’ll find yourself having fewer mood fluctuations, feeling happier overall, and experiencing an improvement in your ability to focus.
Note that we are not discouraging anyone from taking pharmaceutical medications, especially if your doctor recommends them. In fact, these can be lifesavers for a lot of people.
The good news, however, is that more options are now available today to help you overcome mental health challenges. Start with looking at the food you’re currently eating and make small changes day by day. Make sure you keep a diary to track your progress, so you can see how much you’ve improved over time.
Recipe Spotlight: Crunchy, Roasted Spicy Chickpeas
Speaking of the food you’re eating, here’s a recipe that you can try today to help your mood.
This salty snack is the perfect alternative to the bag of chips you may be craving when you’re stress eating. It combines the aromatic and flavorful tastes of cumin, garlic, pepper, onion, coriander, and turmeric to give you something healthy (and crunchy) to nibble on during the day. You can also serve this as an appetizer. Enjoy!
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