Food, the Brain & Mental Well-Being

October 10th is World Mental Health Day, dedicated to raising awareness about mental health and encouraging support for mental well-being around the world. In 2026, the World Health Organization's theme is “Lived experiences heard: real voices, real change,” highlighting the importance of listening and meaningfully including people with lived experience in mental-health care and policy.¹

While nutrition is not the whole story when it comes to mental health, food is one piece of the bigger picture. Our brain needs energy and nutrients to function and emerging research continues to explore the relationship between nutrition, the gut, the brain, and mental well-being. 

Let’s take a closer look, noting: there is no single “perfect” diet for mental health, and food is not a replacement for mental-health treatment or support. 

What is Mental Health? 

The World Health Organization defines mental health as a state of mental well-being that helps us cope with the stresses of life, realize our abilities, learn and work, and contribute to our communities.¹ 

Mental health is influenced by many factors, including biology, genetics, relationships, environment, socioeconomics, sleep, stress, access to healthcare, and more. As mentioned before, nutrition is one part of this very large puzzle. 

Globally, nearly 1 in 7 people, or about 1.2 billion people, were living with a mental disorder in 2023, according to the latest WHO estimates. Anxiety and depressive disorders are among the most common.²

That is a lot of people, and a reminder that mental health deserves the same attention, compassion and care given to physical health. 

Your Brain is a Hungry Organ 

The brain may be relatively small compared to the rest of the body, but it requires a large amount of energy. Although the brain accounts for only about 2% of body weight, it uses roughly 20% of the body’s energy at rest.³

Its preferred fuel under typical conditions is glucose, although the brain can use other fuel sources, such as ketones, during prolonged fasting or carbohydrate restriction.⁴

And the brain isn’t just an energy-hungry organ, it is also lipid-rich. Approximately 50-60% of the brain’s dry weight consists of lipids (fats), which are important components of cell membranes and other structures within the nervous system.⁵

This is one reason dietary fats, particularly essential fatty acids and long-chain omega-3 fatty acids such as DHA, are of interest in brain research. DHA is highly concentrated in brain cell membranes and plays important structural and signaling roles.⁶

But, more omega-3 does not automatically equal better mental health. Research into omega-3s and mental health conditions is ongoing, and food sources should be considered within the context of an individual’s overall dietary pattern. 

Meet Your Neurotransmitters 

Neurons communicate using electrical and chemical signals. Neurotransmitters are chemical messengers involved in communication between neurons and between neurons and other cells. 

Some key neurotransmitters include: 

• Acetylcholine: involved in attention, learning, memory, and muscle activity 

• Dopamine: involved in motivation, reward, movement, learning and cognition 

• Glutamate: the brain’s major excitatory neurotransmitter, with important roles in learning and memory 

• Histamine: involved in wakefulness, arousal, and other processes 

• Norepinephrine: involved in attention, arousal, stress responses, and other functions 

• Serotonin: involved in mood, sleep, appetite, gastrointestinal function, and many other processes 

These chemical messengers are influenced by a complicated network of biological processes. Nutrients provide some of the building blocks and cofactors involved in those processes, but it is far too simplistic to say that eating a particular food will “boost” a neurotransmitter. 

The Gut Brain Connection 

If you have ever had “butterflies” in your stomach before a big presentation, you’ve experienced a tiny glimpse of the gut-brain connection. 

The gut-brain axis describes the two-way communication between the gastrointestinal tract and the brain. This communication involved the nervous system, immune system, hormones, metabolic signals, and the trillions of microorganisms that make up the gut microbiome.⁷

Your gut microbiome is individual, influenced by factors including early-life experiences, genetics, diet, medications, lifestyle, environment, and other factors. 

The gastrointestinal tract also contains an extensive network of neurons called the enteric nervous system, sometimes nicknamed the “second brain.” It contains hundreds of millions of neurons and can coordinate many aspects of digestive functions largely on its own.⁸

Researchers are investigating the many ways the gut and brain communicate, including through immune signaling, microbial metabolites, the vagus nerve, and changes in tryptophan metabolism.⁷,⁹

Nutrition & the Brain 

The brain needs a steady supply of energy, protein, essential fats, vitamins, minerals, and other nutrients to support its many jobs. 

Several nutrients are particularly important to normal nervous system functioning, including: 

• Omega-3 fatty acids, EPA and DHA 

• B vitamins 

• Iron

• Zinc

• Magnesium 

• Iodine

• Selenium

• Copper

• Protein and amino acids 

Nutrient deficiencies can affect the nervous system and, in some cases, may contribute to symptoms that overlap with or worsen mental health concerns.¹⁰ This is one reason adequate nutrition matters and individualized nutrition care can be useful. 

Can Food Improve Mental Health? 

Research increasingly finds associations between overall dietary patterns and mental health. Diets rich in vegetables, fruits, whole grains, legumes, nuts, seeds, seafood, and other minimally processed foods are often associated with better mental-health outcomes. 

Mediterranean-style dietary patterns have received particular attention. Some randomized trials and systematic reviews suggest that dietary interventions may improve depressive symptoms, while other recent reviews found little or uncertain evidence because of small studies, methodological limitations, and differences between interventions.¹¹⁻¹⁴

So, while nutrition is a promising area of mental health research, we cannot currently say that a particular diet prevents or treats mental illness for everyone. 

What we can say is that nourishing the body is one component to supporting overall health and nutrition can be part of a broader mental-health care plan. 

There is no “Perfect” Mental-Health Diet

There is no meal plan that works identically for everyone. Food preferences, culture, budget, access to food, medical conditions, medications, allergies, gastrointestinal symptoms, cooking skills, schedule, and personal circumstances all matter. 

A supportive eating pattern should be sustainable and enjoyable. Some questions to consider: 

• Am I eating regularly enough to support my energy needs?

• Am I getting a variety of foods throughout the week?

• Am I including sources of protein, carbohydrates, fats, fiber, vitamins, and minerals? 

• Am I enjoying food? 

• Is my approach flexible to fit my actual life?

• Am I avoiding unnecessary food rules that create more stress than they solve? 

Nutrition is One Piece of the Puzzle 

Mental health is complex, and so is nutrition. Food can support the brain and body, but it cannot solve everything. 

If you’re experiencing anxiety, depression, changes in appetite, difficulty eating, or another mental-health concern, reaching out to a qualified mental-health professional is an important step. A registered dietitian can also work alongside your healthcare team to help you develop a practical, individualized approach to nutrition that supports your health. 

Interested in learning more about nutrition and mental well-being? Contact us at (805) 738-5700 to schedule an appointment with a dietitian. We’re here to help make nutrition feel supportive, personalized, and realistic for your life. 

Stay tuned for Part 3, where we’ll take a closer look at different eating patterns that have been studied in relation to mental well-being, and what the research actually tells us. 

Written by: Lexi Underhill, RDN 

Resources: 

1. World Health Organization. World Mental Health Day 2026: Lived experiences heard: real voices, real change. Published October 10, 2026. Accessed September 28, 2026. WHO World Mental Health Day 2026

2. World Health Organization. Mental disorders. Published September 11, 2026. Accessed September 28, 2026. WHO Mental Disorders Fact Sheet

3. Magistretti PJ, Allaman I. A cellular perspective on brain energy metabolism and functional imaging. Neuron. 2015;86(4):883-901. doi:10.1016/j.neuron.2015.03.035. 

4. Rao J, Oz G, Seaquist ER. Regulation of cerebral glucose metabolism. Minerva Endocrinol. 2006;31(2):149-158. 

5. National Research Council. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press; 2005. (Brain lipid composition summarized in NCBI review.) NCBI: Essential Fatty Acids and Cognitive Function

6. Mallick R, Basak S, Duttaroy AK. Docosahexaenoic acid, 22:6n-3: Its roles in the structure and function of the brain. Int J Dev Neurosci. 2019;79:21-31. doi:10.1016/j.ijdevneu.2019.10.004. 

7. Cryan JF, O'Riordan KJ, Cowan CSM, et al. The microbiota-gut-brain axis. Physiol Rev. 2019;99(4):1877-2013. doi:10.1152/physrev.00018.2018. 

8. O'Malley D. The brain-gut axis: clinical implications. Gastroenterol Hepatol. 2019;15(4):195-205.

9. Gershon MD. 5-Hydroxytryptamine (serotonin) in the gastrointestinal tract. Curr Opin Endocrinol Diabetes Obes. 2013;20(1):14-21. 

10. Zielińska M, Łuszczki E, Dereń K. Dietary nutrient deficiencies and risk of depression: review article 2018-2023. Nutrients. 2023;15(11):2433. doi:10.3390/nu15112433. 

11. Jacka FN, O'Neil A, Opie R, et al. A randomised controlled trial of dietary improvement for adults with major depression (the “SMILES” trial). BMC Med. 2017;15:23. doi:10.1186/s12916-017-0791-y. 

12. Bizzozero-Peroni B, Martínez-Vizcaíno V, Fernández-Rodríguez R, et al. The impact of the Mediterranean diet on alleviating depressive symptoms in adults: a systematic review and meta-analysis of randomized controlled trials. Nutr Rev. 2025;83(1):29-39. doi:10.1093/nutrit/nuad176. 

13. GBD 2023 Mental Disorder Collaborators, Khan MU. Updated trends in the global prevalence and burden of mental disorders, 1990-2023: a systematic analysis for the Global Burden of Disease Study 2023. Lancet. 2026;407(10543):2040-2064. doi:10.1016/S0140-6736(26)00519-2. AAston Research Explorer

14. Effect of Different Dietary Patterns on Patients with Depressive Disorders: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Published 2025.