How is Nutrition Related to Mental Health?
What if I told you that what we eat doesn’t just affect the physical health of our brain, but can also influence our mental health and wellbeing?
It may come as no surprise that the human brain is my favorite organ - it is just so fascinating and complex! It is the command center for our nervous system and is responsible for many of the functions we use on a day-to-day basis, such as our ability to move, communicate, form thoughts and memories, make decisions, problem-solve, and process emotions. Because the brain controls so many of our daily functions, it is arguably the most valuable organ in the human body.
Though our brain is incredibly sophisticated, it is just as vulnerable to disease and disorders as any other part of our body, so it is important to protect and care for it as we would our heart, liver, or kidneys.
There are many lifestyle factors that play an integral role in brain health, such as managing stress, staying socially connected, engaging our brain in activities, physical movement, and getting a good night's sleep(1). However, there is one lifestyle factor in particular that has been gaining a lot of attention over the past decade as a modifiable component of mental health, and that is food intake(2,3).
Nutrients, Brain Structure, and Performance
You can not talk about the relationship between nutrition and mental health without first discussing the role that nutrients play in the overall structure and inner workings of the brain.
The human brain is primarily made up of water and fat. In fact, 60% of your brain is composed of fat, with high concentrations of polyunsaturated fatty acids (PUFA)(4,5). Proteins help brain cells (neurons) to communicate with each other through neurotransmitters, which are made from amino acids, the building blocks of proteins(6). Neurotransmitters also rely on nutrient cofactors, such as vitamins and minerals, to function properly(7). The brain has very high energy demands, even at rest, consuming on average 20% of a person’s daily caloric intake(8). Much of this energy comes from the carbohydrate, glucose, the brain's preferred energy source(9). Because the brain is so metabolically active, it is vulnerable to oxidative stress. Antioxidants from our diet are required to maintain a balance between oxidative stress and antioxidant system as well as the structural integrity and optimal functions of the brain(10,11).
The Relationship Between Food and Mood Goes Both Ways
It is clear that the nutrients within our food are essential for the overall physical health of the human brain, but how does the food we eat impact our mental health? A person’s physical health and mental health are very much intertwined; when you take care of your physical health your mental health benefits.
There are three main mechanisms through which the food we eat can affect our mental health(11,12,13):
The health of our gut microbiota
Oxidative stress and Inflammation
Interestingly, our mental state can also influence our food choices through dysregulated eating, effects of medication, and food insecurity (14,15,16,17). For example, when we feel depressed or anxious, our appetite is typically lowered, and our food consumption goes down. In this state, it is also common to feel fatigued and less motivated to prepare a meal, so when we do eat, we are likely to make poor food choices, such as gravitating toward convenience foods, take-out meals, and stimulants (such as sugar and caffeine). These poor food choices tend to be less nutrient-dense and can make us feel less than optimal, and so the vicious cycle continues.
What to Eat for Improved Mental Health
Although there is no single almighty brain food that can ensure optimal brain functioning, there is compelling evidence to show that focusing on healthy eating patterns, such as the Dietary Approaches to Stop Hypertension (DASH) and the Mediterranean diet, may slow cognitive decline and nurture good mental health(18,19).
The DASH and Mediterranean dietary patterns focus on food categories that are nutrient-dense, help nourish the gut, and lower inflammation, such as :
Dark Leafy Greens
Dark leafy greens, including kale, spinach, collards, Swiss chard, arugula, beet greens, mustard greens, watercress, etc. are excellent sources of folate. Folate is essential for the creation and functioning of neurotransmitters, such as serotonin, dopamine, and norepinephrine, that play a role in mood disorders(20). Greens also contain a wide range of nutrients that have been shown to have neuroprotective effects on cognitive decline, such as the antioxidants lutein and kaempferol, vitamin E, and vitamin K(21).
All Other Vegetables
Research suggests that inflammation underlies many conditions of the brain(11). To counteract the effects of inflammation, we need a diet rich in colorful foods. A diet diverse in vegetables of varying types and colors (green, orange, red, purple, etc.) provides the body with an abundance of different vitamins, minerals, and antioxidants needed to protect the body from oxidative stress and inflammation(22).
Similar to vegetables, berries also pack a huge nutritional punch, containing many vitamins, minerals, and flavonoid antioxidants. The antioxidant compounds in berries have many positive effects on the brain, including improving communication between brain cells, reducing inflammation, increasing plasticity, boosting learning and memory, and slowing cognitive decline(11,22). Antioxidant-rich berries include strawberries, blackberries, raspberries, blueberries, blackcurrants, and mulberries.
Legumes and Pulses
Legumes include chickpeas, beans, edamame, lentils, split peas, etc. These plant foods are great sources of protein and fiber, both of which help to maintain stable and consistent blood sugar levels and minimize blood sugar spikes and dips that can impact our mood. Legumes and pulses are also rich in B-vitamins, which have been shown to improve verbal and memory performance and may delay the onset of Alzheimer’s disease(23,24).
Nuts and seeds
Eating more nuts and seeds may also be beneficial for brain health, as some contain omega-3 fatty acids and are rich sources of fiber, antioxidants, Vitamin E, and magnesium. For example, walnuts have a high concentration of Omega-3 fatty acids, which has been associated with improved depression scores and cognitive performance in adults, as well as slowed age-related cognitive decline(25). Almonds, pecans, and hazelnuts contain high concentrations of vitamin E and Brazil nuts and pine nuts are loaded with selenium, both of which are powerful antioxidants(26,27,28). In addition to the nuts mentioned above, pumpkin seeds provide the body with tryptophan, an amino acid responsible for producing mood-boosting serotonin(29).
Whole grains include grains like wheat, corn, rice, oats, bulgur, barley, quinoa, sorghum, millet, spelt, and rye. They are naturally high in fiber and contain unique antioxidants not found in fruits and vegetables, as well as B vitamins, vitamin E, magnesium, and iron(30). Whole grains provide carbohydrates to fuel the brain and fiber to help slow digestion, allowing for a gradual release of sugar into the bloodstream to keep your energy levels stable(31).
Fatty fish, such as salmon, mackerel, tuna, herring, and sardines are excellent sources of two types of omega-3s — docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which are linked to lower levels of depression and enhanced cognition and thinking abilities(32,33,34). Omega-3s are also major building blocks of the brain and help construct and maintain the structure of membranes around brain cells (neurons)(35). Not a fan of fish? No problem. Omega 3’s can also be obtained from soybeans, nuts, flax seed, flax seeds oil, hemp seeds, and some seaweed and algae.
Chicken and turkey provide lean protein that can help to stabilize blood sugar concentrations, keeping your mood and energy levels steady throughout the day(36,37). Speaking of mood, poultry is also an excellent source of the amino acid tryptophan, which helps create mood-boosting serotonin(38). In addition to their protein content, chicken and turkey also contains dietary choline and vitamins B6 and B12. B vitamins have been shown to play important roles in healthy cognition and provide neuroprotective benefits(38). Choline is an essential building block in acetylcholine, a neurotransmitter that helps with memory(39).
Extra Virgin Olive Oil
Extra virgin olive oil (EVOO) is a major component of the Mediterranean diet. It is praised for its high antioxidant content and has significant anti-inflammatory properties that protect cells under oxidative stress(40). Studies have shown that the nutritional elements contained in EVOO may reduce risk for Alzheimer’s disease and dementia, enhance learning and memory, and support mental health(41,42).
There is a growing body of research linking gut health with mental health(43). Several studies have found that microorganisms living in your gut, including probiotics, can play a key role in mood regulation by helping to reduce inflammation, produce neurotransmitters, and influence stress response(44,45). Foods that contain probiotics include kimchi, kombucha, miso, sauerkraut, tempeh, tofu, kefir, and yogurt.
In summary, nutrition plays a vital role in our mental health. Not only does the food we eat have a direct impact on the physical structure, development, and day-to-day functioning of our brain, but it also affects our emotional and mental health through complex mechanisms such as the gut-brain axis, nutrient deficiencies, and oxidative stress and inflammation. This relationship is also bi-directional, as our mental state can also influence the foods we eat. There is no magic superfood that can improve our mental health, but following dietary patterns such as the Mediterranean and DASH diet, that emphasize fruits and vegetables, lean protein, fish, nuts, legumes, whole grains, and olive oil may help slow cognitive decline and nurture good mental health.
At The Daily Grind Nutrition, I teach my clients how to add brain-nourishing foods to their current diet in a way that works for their personal tastes and lifestyle. To learn more about my practice philosophy and how I help women living with anxiety and depression navigate their symptoms and discover the ways in which their food choices, dietary patterns, and lifestyle behaviors may be impacting their mental health, book a free Discovery Session.