Nutrition and Mental Health: the Gut Brain Axis and More

It’s amazing to consider how much of our total daily energy is utilized by the brain! This one organ uses around 20 percent of the body’s total energy each day—and, for the brain to function at its best, it needs glucose for energy. The brain also utilizes neurotransmitters, formed from protein, which regulate signals within the nervous system. In addition to these macronutrients, the brain needs various micronutrients to function well. Some of these include B vitamins, choline, folate, magnesium, vitamin C, vitamin E, zinc, and vitamin D.  

The food you eat, then, can play a significant role in how optimally your brain can function. If, for example, the brain is fueled with nutrient-dense nourishing foods, it can function more efficiently. If, though, the brain is not receiving the nourishment it needs, then it doesn’t have the resources to function at its best. 

Not surprisingly, then, mental health is one area where the concept of food as medicine is especially relevant. Food has the ability to be both inflammatory and anti-inflammatory, depending on the degree of processing, amount of phytonutrients, preparation techniques, cooking methods and, in the case of meat, how animals are raised and what they eat. Because of this, choosing foods that are supportive of brain health can have a large impact on one’s well being. There are few underlying factors that relate to nutrition for brain health, which will be discussed in further detail below.

Insulin Resistance and Type 3 Diabetes

Research done in recent years has investigated the link between insulin resistance and mental health. In addition to some non-preventable factors like genetics and hormonal disorders, insulin resistance is also related to a few preventable, lifestyle-related factors, including: 

• Consumption of ultra-processed foods (for example, Doritos and breakfast cereal): These generally consist of a list of >five ingredients—some of which are not in their naturally occurring form. 
• Consumption of simple carbohydrate foods (for example, candy and fruit juice): These absorb quickly and generally do not contain fiber to slow down the impact on blood sugar levels. 
• Lack of physical activity: We encourage finding regular ways to move that feel good in your body and increase your heart rate, which increases blood flow to the brain.  

A Dutch study carried out by Stanford researchers found that insulin resistance was linked to an 89 percent increase in the rate of new cases of major depressive disorder. In addition, people who develop prediabetes have 2.6 times the risk for major depression. Plus, a 2015 study published in “Proceedings of the National Academy of Sciences in the U.S” found that brain insulin resistance alters dopamine (a hormone related to satisfaction and motivation) and causes symptoms of anxiety and depression. 

Insulin resistance is also known to impact Alzheimers; this is often referred to as type 3 diabetes. Eating a diet full of fruits, vegetables, whole grains, complex carbohydrates, high quality fats, and protein can help to minimize risk of insulin resistance and prevent negative impacts on mental health. 

The Gut Brain Axis and the Microbiome

Up and coming research has been exploring the relationship between the gut and the brain— known as the gut brain axis. The gut produces many of the same neurotransmitters that the brain does, which have a lot to do with mood regulation. It is known that 90 percent of serotonin, which is known as the “feel good” hormone, is produced in the gut. The gut also produces a neurotransmitter called GABA (gamma-aminobutyric acid), which can control feelings of anxiety. 

It has been found that there are around 500 million neurons in the gut that are connected to the brain through nerves. One of the most important nerves relating to the parasympathetic nervous system is the vagus nerve (also known as the wanderer nerve). It can send stress signals to the brain, and research has shown that stress inhibits the signals sent through the vagus nerve. This can lead to poor digestion and GI issues.

A few simple ways to improve vagal tone include: 

• Singing
• Humming
• Gargling 
• Chanting

In addition to neurotransmitters, gut microbes regulate the immune system, which relates to inflammation, and high inflammation is linked to mental health challenges. Specifically, toxins made by bacteria in the gut can cause inflammation if passed from the gut into the blood. This can occur when a condition sometimes known as the leaky gut syndrome or, more accurately, increased intestinal permeability occurs. 

The take home message: a healthy microbiome can lead to a healthier brain, and a healthy brain can lead to a healthier microbiome. An intake of many high quality nutrients while avoiding excess stress and gut disruptors (such as non-steroidal anti-inflammatory drugs, alcohol, and unnecessary antibiotics) has the power to improve both gut and brain health. 

Below, the effects of specific nutrients on nervous system function are explained. These nutrients are typically available when following a diet that includes a plethora of fruits and vegetables, high quality fish and meat, nuts and seeds, whole grains, and low amounts of processed food and refined sugars. 

• Omega-3s: foods such as fatty fish (S.M.A.S.H fish), chia seeds, walnuts, flax, eggs, soybeans, and brussels sprouts:
• DHA and EPA (types of omega-3 fatty acids) are important for brain development, aid in learning, and have also been found to improve depression symptoms.
• There is evidence that a high omega-6 (and low omega-3) diet is more likely to lead to symptoms of depression.
• B vitamins: food sources, including salmon, leafy greens, liver, eggs, and milk can:
• help with cognitive performance
• preserve memory during aging
• Magnesium: food sources include spinach, dark chocolate, cashews, beans, pumpkin seeds, chia seeds, almonds, and soy, and these can:
• promote learning and memory; play a role in serotonin and other neurotransmitter systems; help with proper nerve transmission; and protect against oxidative stress 
• Glucosinolates: sulfur containing compounds in brassica family vegetables can:
• support natural detoxification, helping to increase blood flow to the brain, which can reduce oxidative stress
• Calcium: some food sources include seeds, cheese, yogurt, salmon, sardines, beans, and lentils, which:
• aids in nerve transmission and is involved in memory formation, metabolism, and cell growth
• Selenium: food sources include fish, brazil nuts, eggs, brown rice, sunflower seeds, mushrooms, oatmeal, and spinach, and:
• may be involved in the dopamine pathway 
• this provides antioxidant properties, being involved in motor performance, coordination, and memory/cognition
• Vitamin D: food sources include cod liver oil, salmon, tuna, mushrooms (exposed to sunlight), and fortified foods, which can:
• prevent neurodegenerative disorders by regulating neurotransmitter release and preventing oxidative damage
• lower risk of schizophrenia and depression
• reduce the severity of depression, irritability, fatigue, mood swings, sleep difficulties, weakness, and the ability to concentrate in adolescents diagnosed with depression

• Vitamin C: food sources include citrus fruits, tomatoes, potatoes, peppers, kiwi, and strawberries, and this is:
• involved in proper neuron functioning, reducing inflammation due to its antioxidant activity, and helping with growth and repair of body tissues
• Vitamin E: food sources include sunflower seeds, almonds, beet greens, and red bell pepper, and:
• alpha-tocopherol found in E vitamins helps to protect the nervous system from oxidative damage 
• Carotenoids: food sources include spinach, kale, corn, bell peppers, tomatoes, and broccoli with powerful anti-inflammatory properties
• SAM-e (S-adenosylmethionine): food sources that can support production involve consuming enough high quality protein, and: 
• these are formed in the body from adenosine and methionine, which plays a role in methylation (lack of methylation can lead to low dopamine, which can cause lack of focus, concentration, short-term memory, emotional stability, and hormone regulation)
• Other minerals that help to protect against oxidative stress include: 
• Manganese: food sources include mussels, brown rice, hazelnuts, chickpeas, spinach, pineapple, whole wheat, and potatoes 
• Zinc: food sources include high-quality meat, shellfish, legumes, seeds, nuts, dairy, and whole grains 
• Copper: food sources include liver, oysters, spirulina, shiitake mushrooms, nuts and seeds, lobster, leafy greens, and dark chocolate

Diversity is key! Eating a variety of whole foods that are as close to their natural form as possible is the best way to make sure that you are taking care of your mental health. 

Although what we eat has a significant impact on mental health, supporting mental health requires a truly holistic integrative approach. So, also consider lifestyle factors such as the following:

• Quality of sleep and duration of sleep
• Exposure to stress and management techniques used
• Daily activity level
• Relationships and connections with others
• Environmental exposures 
• Living environment

Mindful Eating

It is also worth noting that the way in which you eat your food can impact the effect it has on your body, including how it is digested. Mindful eating is one way to lower stress levels, improve digestion, enhance our relationship with food, and to be present while eating meals. If you are not familiar with this technique, you can visit The Center for Mindful Eating (TCME) to learn more. Plus, you can also check out our blog post titled “Mindful Eating and a Healthy Relationship With Food.” 

Support on Your Journey

It is important to talk to your healthcare provider if you are struggling with your mental health and to realize that you are not alone. It’s okay to ask for help. At Farmer Jones Farm, we are here to support you on your mental health journey by providing nutrient-dense regeneratively raised vegetables delivered right to your doorstep. You may wish to check our build your own box collection for brain health or to try our Eat the Rainbow box, which is packed with color and antioxidants that help to reduce inflammation. 

Resources

1. Kleinridders A., Cai W., Cappellucci L., Ghazarian A., Collins W.R.,  Vienberg S.G.,  Pothos E.N.,  Kahn C.R.. (2015, March 17). Insulin resistance in brain alters dopamine turnover and causes behavioral disorders. Proceedings of the National Academy of Sciences of the United States of America. https://pubmed.ncbi.nlm.nih.gov/25733901/ 
2. MD, E. S. (2022, September 18). Nutritional psychiatry: Your brain on food. Harvard Health. https://www.health.harvard.edu/blog/nutritional-psychiatry-your-brain-on-food-201511168626 
3. News Center. (2021, September 22). Insulin resistance doubles risk of major depressive disorder, Stanford Study finds. News Center. https://med.stanford.edu/news/all-news/2021/09/insulin-resistance-major-depressive-disorder.html#:~:text=By%20all%20three%20measures%2C%20the,cases%20of%20major%20depressive%20disorder.