Nutrient Deficiencies That Can Impact Your Mental Health — and How to Support Your Brain Through Food

Introduction

Have you ever felt down, foggy, or anxious and thought, “I’ve tried everything — maybe there’s something missing”? It’s possible you’re not getting enough of the right nutrients.

Our brains run on food, just like our bodies. When key vitamins, minerals, and fats are missing, it can show up as low mood, poor focus, anxiety, or just feeling “off.”

In this post, we’ll explore what the research says, which nutrients matter most for mental health, and simple steps you can take to support your brain and mood.

Why Nutrients Matter for Your Mood and Brain

Your brain is always working. It thinks, processes, remembers, feels, and regulates your entire body. All that work requires a steady supply of nutrients.

Research shows that low levels of certain vitamins, minerals, and healthy fats are linked to mood issues, anxiety, brain fog, and symptoms of depression.

For example:

• Diets low in whole foods can increase inflammation.
  
• Poor gut absorption can reduce nutrient levels.
  
• Stress and lack of sleep increase nutrient demand.
  

Food matters — but nutrient deficiency matters even more.

Key Nutrients Linked to Mental Health

Below are some of the most studied nutrients that support mood, energy, and brain function.

1. Omega-3 Fatty Acids

Omega-3 fats help:

• Build brain cells
  
• Reduce inflammation
  
• Support neurotransmitter function
  

Low omega-3 intake is linked with higher depressive symptoms.

Best food sources:

• Salmon
  
• Mackerel
  
• Sardines
  
• Walnuts
  
• Flaxseed and chia seeds
  

2. B Vitamins (B12, Folate, B6)

These vitamins help make serotonin, dopamine, and other mood-supporting chemicals.

Research highlights:

• Low folate is associated with increased depression risk.
  
• Low B12 is linked with cognitive decline and mood disorders.
  

Food sources:

• Leafy greens
  
• Lentils and beans
  
• Eggs
  
• Meat and fish (especially for B12)
  
• Fortified grains
  

3. Vitamin D

Vitamin D regulates mood, immunity, and inflammation. Deficiencies are common, especially in winter or in people with limited sun exposure.

Low vitamin D has been linked with:

• Depression
  
• Anxiety
  
• Cognitive issues
  

Sources:

• Sunlight
  
• Fatty fish
  
• Fortified milk or cereal
  
• UV-treated mushrooms
  

4. Zinc, Magnesium, Iron, and Selenium

These minerals carry out hundreds of brain and mood-related functions.

Zinc supports neurotransmission and immune balance.
Magnesium helps calm the nervous system and supports sleep.
Iron supports energy and brain health.
Selenium helps regulate thyroid function, which affects mood.

Food sources:

• Nuts and seeds
  
• Whole grains
  
• Meat and seafood
  
• Beans and lentils

What Research Shows

Here are key findings in simple terms:

• People with depression often have lower levels of B12, zinc, and other micronutrients.
  
• Low vitamin D is consistently associated with mood disorders.
  
• Poor nutrient intake can increase inflammation and stress-hormone activity.
  
• Improving nutrient levels can support mood and treatment outcomes.
  

Nutrients aren’t the only cause of mood issues — but they are a meaningful contributor.

Why You Might Have a Nutrient Deficiency

Even if you try to eat well, deficiencies can still happen due to:

• Processed or fast-food-heavy diets
  
• Vegan or vegetarian diets without planning (B12, iron, zinc risks)
  
• Gut issues that affect absorption
  
• Low sunlight exposure
  
• Chronic stress
  
• Certain medications (like PPIs or metformin)
  
• Alcohol use
  
• Aging, which reduces nutrient absorption
  

This is why testing and a personalized plan can be so helpful.

How to Support Your Brain and Mood With Food

These steps are simple, realistic, and based on the science of nutritional psychiatry.

1. Build a “Brain-Supportive” Plate

Aim for:

• Bright vegetables and fruits
  
• Lean protein or plant protein
  
• Whole grains and fiber-rich carbs
  
• Omega-3 rich foods
  
• Nuts and seeds
  

This pattern fuels your brain, reduces inflammation, and supports gut health.

2. Target Key Nutrients (With Guidance)

You may want to ask your provider to test:

• Vitamin D
  
• Vitamin B12
  
• Folate
  
• Iron
  
• Zinc
  
• Magnesium
  

Food first is ideal — but supplements may help if deficiency is confirmed.

3. Support Your Gut to Improve Absorption

Your gut has to absorb the nutrients you eat.

To support gut health:

• Eat fermented foods (yogurt, kefir, sauerkraut)
  
• Increase fiber intake
  
• Reduce alcohol
  
• Avoid unnecessary NSAIDs
  
• Manage stress (it affects the gut lining!)
  
• Prioritize sleep
  

Healthy gut → better absorption → better mood.

4. Lifestyle Foundations Matter Too

Your body uses nutrients more effectively when:

• You sleep 7–9 hours
  
• You exercise regularly
  
• You manage stress
  
• You limit alcohol
  
• You avoid smoking
  

These simple steps protect the brain–gut–nutrition cycle.

Bottom Line

Your brain needs quality fuel. When nutrients run low, mood, energy, and clarity can suffer. By supporting your nutrition, your gut, and your lifestyle, you give your brain what it needs to feel calmer, clearer, and more resilient.

You don’t need perfection. Small steps create meaningful change.

Next Steps: How Dr. Lewis Can Support You

If you’re dealing with mood symptoms, fatigue, or brain fog — and feel like something deeper is going on — we’re here to help.

Start Here

 Explore the BLISS Protocol
Our signature program blends psychiatry, functional medicine, nutrition, and lifestyle therapy to identify root causes and build a personalized plan.

Book a Consultation
We’ll explore your symptoms, run targeted testing if needed, and create a holistic plan to help you feel better — inside and out.

References

1. Muscaritoli, M., et al. (2021). The Impact of Nutrients on Mental Health and Well-Being. Frontiers in Nutrition.
   
2. Baik, H. W., & colleagues. (2024). Mental health and micronutrients: a narrative review. ACNM Journal.
   
3. Zielińska, M. (2023). Dietary Nutrient Deficiencies and Risk of Depression.
4. UPMC HealthBeat. (2021). 7 Nutritional Deficiencies Linked to Depression.
5. Cart, C. (2025). Micronutrients, Phytonutrients, and Mental Health. Institute for Functional Medicine.