Mood can fluctuate throughout the day and is shaped by external circumstances, such as those that happen throughout the day, as well as internal factors like blood sugar balance, hydration, and nutrient status.^1-4 Emerging evidence, sometimes referred to as nutritional psychiatry, shows that what your clients eat has a measurable impact on how they feel.^1,2 While diet alone isn’t a treatment for mental health conditions such as depression or anxiety, strategic dietary and lifestyle choices can support more stable, positive moods for your clients. Healthcare providers can help patients improve their mood and emotional well-being in real time through evidence-based dietary strategies.

Dietary Patterns and Macronutrients for Brain and Mood Health

Mood is closely tied to how the brain is fueled and the neurotransmitters it makes. Glucose is the brain’s preferred energy source, requiring a steady supply of about 130 grams from the diet daily (or an acceptable macronutrient distribution range of 45-65% for carbohydrates of total calories) to function optimally.⁵ Dietary carbohydrate sources include grains, vegetables, fruits, pulses/legumes, nuts, seeds, and dairy foods.⁵ Studies have linked carbohydrate-containing foods to positive outcomes for mental health and mood.^1,3 Complex carbohydrates trigger the release of neurotransmitters such as serotonin, which contribute to feelings of well-being and happiness.⁴

When blood sugar drops too low, mood often follows, and low blood sugar can trigger anxiety in some people.⁶ The body can mobilize its glucose stores (glycogenolysis) when low blood glucose levels trigger the hormone glucagon to release glucose from liver stores.⁶ If dietary carbohydrate intake isn’t high enough to fuel the brain adequately, the body can rely on gluconeogenesis, which creates glucose from non-carbohydrate sources such as amino acids, lactate, and glycerol, which can create ketones.⁷ Studies so far on ketogenic/very low-carb diets and mood are promising. One small 6-week intervention study (n=12 ketogenic intervention, n=12 low-fat intervention, n=13 control) showed potential benefit to mood and cognition for the ketogenic intervention group. More studies are needed to determine the role of carbohydrates in mood. 

Protein is also essential for mood regulation. Foods containing the amino acid tyrosine (dairy, soy, legumes, eggs, chicken, turkey, beef, fish) help synthesize dopamine and norepinephrine.¹ These neurotransmitters help regulate mood, concentration, and feelings of motivation.¹  Healthy dietary fat intake also plays an anti-inflammatory role in brain health and has been linked in some studies to improved mood, reduced depression, and enhanced cognition, though more research is needed in this area.⁸

Though all three macronutrients – carbohydrates, protein, and fat – play a role in mood, the diet as a whole also makes a difference. Healthcare providers can guide patients toward evidence-based, whole-diet approaches that support mental health. The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) emphasizes plant-forward foods like leafy greens, berries, whole grains, nuts, olive oil, and fish, while limiting red meat, butter, sweets, and processed foods has shown benefit in recent studies for mood, quality of life, and cognitive function.⁹ One pilot randomized control trial (N=41 adult females and males) were randomized into a MIND diet with support group (n=15), MIND diet with no support (n=14), and control group (n=12) for 12 weeks and found that both intervention groups significantly improved measures of cognitive function, mood, and quality of life scores, indicating that the diet itself can be a positive intervention.⁹ MIND diet aside, observational studies have shown that “healthy” eating patterns that align with the healthy eating index score (HEI), Mediterranean diet, vegetarian diet, and anti-inflammatory dietary patterns are associated with lower anxiety symptom severity.^3,10 

In contrast to healthy eating patterns, limiting ultra-processed foods may also help stabilize mood. Diets high in ultra-processed products and an “unhealthy” dietary pattern high in added sugar, sugar-sweetened beverages, processed meats, and fast foods rich in refined carbohydrates and saturated fat have been linked in some studies to a higher risk of depression, anxiety, and emotional dysregulation, though more studies are needed in this area.³

Individual Nutrients to Support Mood

While it’s important to consider overall dietary patterns, specific nutrients within healthy patterns are evidence-based to help support your client’s mood. 

B vitamins, particularly folate, B12, and B6, are essential for brain function, supporting neurotransmitter synthesis (e.g., serotonin, dopamine) and driving methylation – a key process that regulates mood through gene expression and neural repair.¹¹ Deficiencies, especially in folate and B12, have been associated with increased risk of depression and longer and more severe depressive episodes.^11-13 With age, levels of B12 and folate can decline, and low levels have been linked to mood disorders. S-adenosyl-L-methionine (SAMe), a compound dependent on adequate B vitamin status, also influences mood-related neurobiological processes.^11,12 B vitamins are easily found in balanced diets. Find B6 in chickpeas, tuna, salmon, chicken, and potatoes, B12 in seafood, dairy foods, eggs, beef, poultry, and fortified cereals and nutritional yeast, and folate in spinach, asparagus, avocado, and broccoli.^14-16

Dietary fiber plays a key role in the gut-brain axis by nourishing beneficial gut bacteria that produce short-chain fatty acids (SCFAs). SCFAs support mood by increasing tryptophan availability, which is needed for serotonin production, and by reducing inflammation by strengthening the gut barrier, which limits immune activation.^13,17 A diverse, fiber-rich diet from whole grains, legumes, fruits, and vegetables supports a healthy gut microbiome and is associated with improved mental health outcomes. A large National Health and Nutrition Examination Survey (NHANES) study (N=8430) showed that participants with higher dietary fiber intake experienced lower inflammation (tested via C-reactive protein (CRP)) and reduced depressive symptoms.¹³ Healthcare providers can help their clients meet the recommended dietary reference intakes (DRIs) of 25g fiber (adult women 19-50 years, or 21g for those over age 51) and 38g fiber (adult men 19-50 years, or 30g for those over 51).¹⁸

Omega-3 fatty acids support brain structure, neurotransmitter function, and inflammation modulation. Though data is still mixed, meta-analyses and clinical reviews have linked higher omega-3 intake with improved outcomes in people with depression.^1,8  While the exact mechanisms are still being explored, their role in neuronal membrane integrity and anti-inflammatory activity offers a promising adjunctive mental health support opportunity.⁷ Healthcare professionals can recommend that their clients increase intake of fatty fish like salmon and sardines, as well as plant-based sources of omega-3s like chia, flaxseed, and walnuts. Supplementation may be helpful for patients with low dietary intake, especially considering bioavailability differences between plant-based (ALA) and marine-based (EPA/DHA) sources.¹⁹

Taking a Holistic Approach to Mood

Mood is influenced by more than just food choices. Health professionals can also address factors like hydration, caffeine, and even adaptogenic herbal support as holistic approaches for their clients. Even mild dehydration can lead to irritability, fatigue, and trouble concentrating, so supporting consistent fluid intake is essential.^13,20 The Institute of Medicine recommends 2.3 liters for women and 3.3 liters for men, daily.²¹ Caffeine may enhance focus, energy, and physical performance in moderation, but studies also show that high caffeine intake is linked with increased risk of anxiety, especially at doses above 400mg (about 4-5 cups of coffee).²²

Adaptogenic herbs such as ashwagandha, rhodiola, holy basil, and ginseng may help regulate the body’s stress response and support mood stability.²³ They work by influencing the hypothalamic-pituitary-adrenal (HPA) axis – a central stress response system that helps regulate cortisol and other stress hormones and key neurotransmitter pathways.²² Preliminary studies and meta-analyses suggest these botanicals offer anxiety-reducing and antidepressant benefits, though further research is needed in this area.²³²

Finally, reinforcing intuitive eating principles like honoring hunger and fullness cues can help patients reduce mental distress. A cross-sectional study (N=990 adults) found, through correlation analysis, that foods and behaviors like exercise, eating breakfast, consuming dairy foods, fruit, and dark leafy veggies, in addition to scoring high on intuitive eating scale and mindful eating questionnaires for having unconditional permission to eat and relying on hunger and satiety cues created better mental health and mood outcomes.²⁴ 

Takeaways for Healthcare Providers

Supporting patients’ mood through nutrition starts with small, sustainable strategies. Encouraging regular meals that stabilize blood sugar through complex carbohydrate and protein intake, promote consistent energy, and provide key nutrients like B-vitamins, fiber, and omega-3 fatty acids can have a meaningful impact on emotional well-being. Guiding patients toward whole-diet patterns like the MIND diet, while addressing hydration, caffeine use, and intuitive eating practices, creates a personalized and holistic approach that healthcare providers can take for mental health. 

References:

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