Most people know that food matters for health, yet the conversation around supplements and brain health can feel confusing.
One day there is a headline saying vitamins are useless and just make expensive urine. The next day there is a study showing that a simple nutrient change protected memory or lowered dementia risk. It is no wonder many people feel stuck between wanting to do something and not knowing what to trust.
Your brain is one of the most metabolically active organs in your body. It is constantly using and recycling nutrients to create energy, repair cells, clear waste, and maintain mood, memory, and focus. When key nutrients are missing or only barely adequate, your brain may cope for a while, then begin to show subtle signs of strain long before there is a formal diagnosis.
Below are four surprising truths about nutrients and your brain that I share with patients in my practice.
Truth One. Multivitamins Do More Than Make Expensive Urine
For years multivitamins have been criticized as unnecessary. Many people have heard the phrase that they only create expensive urine. That idea is now being challenged by large, well-designed clinical trials.
According to a 2025 meta-analysis encompassing 5,535,426 participants, including over 333,943 pregnancies and 904,947 children exposed to maternal supplementation, researchers attempted to answer the question of whether daily multivitamin-mineral supplementation was “worth it.” The synthesis of randomized controlled trials indicated that multivitamin use improved global cognition, episodic memory, and immediate recall in older or cognitively intact adults, reduced psychological symptoms in healthy individuals, and lowered systolic blood pressure in at-risk populations. However, no benefits were found for all-cause mortality, COVID-19 outcomes, visual acuity, or multiple cognitive domains, and a higher risk of age-related macular degeneration progression was reported. Observational studies found associations between multivitamin use and reduced risk of colorectal cancer, coronary heart disease, cataracts, and fragility hip fractures, but not breast or prostate cancer, stroke, or overall mortality. During pregnancy, multivitamin supplementation was linked to reduced risks of small-for-gestational-age births and pediatric cancers, but not to preterm birth, stillbirth, or low birth weight. The researchers also noted that there was a high degree of variability in the definition and doses of a “multivitamin.”
What I take home from this very robust analysis: While a multivitamin may be helpful, targeted and individualized supplementation is likely the better way to go. Taking the right nutrients in the right form can support health in a meaningful way.
This does not mean that every multivitamin on the shelf is right for you. It does mean that a well-formulated, evidence-based multi can help fill common nutritional gaps and support brain function, especially as we age. For many people, a multivitamin is not a luxury but a basic part of brain maintenance, alongside sleep, movement, and stress management, but individualized testing and targeted supplementation is the gold standard.
Truth Two. Vitamin D Is Also a Brain Hormone
Most people think of vitamin D as the sunshine vitamin that keeps bones strong. In reality vitamin D behaves more like a hormone and has powerful effects on the brain. Vitamin D receptors are found throughout the nervous system and help regulate inflammation, immune function, and the expression of hundreds of genes involved in brain health. Vitamin D metabolism is tightly regulated via negative feedback loops involving parathyroid hormone (PTH), calcium, and phosphate levels, similar to endocrine hormones like thyroid hormone.
The Widespread Deficiency Crisis
📊 70% of Americans don’t meet sufficient vitamin D levels (30 ng/mL)
Low vitamin D levels are associated with a higher risk of depression, cognitive decline, and dementia. One large study found that people with healthy vitamin D levels had a significantly lower risk of developing dementia than those who were deficient.
“The goal is not an extreme level. The goal is an optimal range where your brain, bones, and immune system can do their best work.”
Because vitamin D comes mainly from sun exposure and certain foods, many people, especially those who live at northern latitudes, work indoors, or have darker skin, do not reach optimal levels. A simple blood test can tell you where you are starting. With that information your clinician can guide safe supplementation and periodic retesting.
The goal is not an extreme level. The goal is an optimal range where your brain, bones, and immune system can do their best work.
Truth Three. Potassium Protects Your Brain Through Blood Pressure
When we talk about nutrients for the brain, people often think of fish oil or B vitamins. Potassium rarely makes the list, yet it plays a key role in protecting the tiny blood vessels that feed your brain.
Potassium and sodium work together to regulate fluid balance, nerve conduction, and blood pressure. Traditional diets were naturally rich in potassium from fruits, vegetables, beans, and tubers, and relatively low in sodium. Modern diets have flipped that ratio. Many people consume far too much sodium from processed foods and not nearly enough potassium from plants.
📊 96% of Americans don’t meet adequate potassium intake
📊 30% of young adults (ages 20-39) now have hypertension
Low potassium intake is strongly linked to high blood pressure. Over time uncontrolled blood pressure damages the delicate vessels in the brain and increases the risk of stroke and silent brain injuries that accumulate slowly and affect memory and processing speed.
Why This Matters for Your Brain
Your brain’s vasculature is extraordinarily delicate. Approximately 90% of the blood vessels surrounding and penetrating the brain are tiny capillaries with diameters smaller than a human hair. When blood pressure is chronically elevated, these microscopic vessels begin to constrict and deteriorate, starving neurons of oxygen and nutrients.
Food-First Approach
The good news is that potassium is a food-first nutrient. These foods are naturally rich sources:
🥬 Leafy greens (spinach, Swiss chard, beet greens)
🥑 Avocados
🍠 Potatoes and sweet potatoes
🍌 Bananas and other fruits
🫘 Beans and lentils
For most people the focus is not on taking a potassium pill but on building meals that give your body and brain the potassium they have been missing.
Important: Anyone with kidney disease or on certain medications should only make big potassium changes under medical supervision.
Truth Four. Omega-3 Fatty Acids and Magnesium Are Hidden Brain Allies
Two other nutrients often show up together in brain optimization work: omega-3 fats and magnesium.
Omega-3 Fats: Building Blocks of Brain Health
Omega-3 fats, especially EPA and DHA, are structural building blocks of brain cell membranes. They help keep cell membranes flexible, support communication between neurons, and calm inflammation.
Clinical studies have shown that people with higher omega-3 status tend to have better memory, more stable mood, and lower levels of inflammatory markers. In one experiment, volunteers were given a substance that triggers temporary inflammation and depressive symptoms. Those who had been taking EPA-rich omega-3 supplements were protected and did not experience the same drop in mood.
Research Highlight: In a 2025 Journal of Nutrition study, EPA omega-3 supplementation prevented inflammation-induced depressive symptoms in controlled studies. (PMID: 41291772)
Best Sources:
- Fatty fish (salmon, sardines, mackerel) 2-3 times weekly
- High-quality fish oil supplements with significant EPA content
- Algae-based supplements for plant-based diets
💡 Pro Tip: A blood test called the omega-3 index can show whether your current intake is enough or if your brain may benefit from more support.
Magnesium for relaxation, sleep, and resilience
Magnesium participates in hundreds of enzymatic reactions, many of which are directly related to the brain and nervous system. It helps regulate the stress response, supports deep sleep, stabilizes electrical activity in the brain, and contributes to neuroplasticity, the brain’s ability to adapt and form new connections.
Modern diets and farming practices have made magnesium insufficiency common. Many people do not eat enough magnesium-rich foods such as leafy greens, nuts, seeds, and whole grains. Stress, certain medications, and digestive issues can further deplete magnesium stores.
Low magnesium can show up as muscle tension, headaches, poor sleep, anxiety, or a sense that your system is always slightly over-activated. The right form and dose of magnesium, chosen with the help of a clinician, can be a gentle but powerful tool for nervous system regulation and brain health.
Wondering about your own nutrient status? We offer comprehensive testing and personalized brain health optimization. Schedule a consultation at Make An Appointment or call 8582154935.
How To Work With Nutrients Safely and Effectively
Nutrients are powerful. The goal is not to grab random supplements off the shelf, but to work in a structured, thoughtful way. In my practice I guide people through four basic steps.
One: Test and Do Not Guess
Where it is appropriate and available we begin by measuring nutrient status. Depending on the situation this may include blood tests for vitamin D, B vitamins, ferritin, or omega-3 index, and sometimes more specialized panels. Testing shows us where you are starting and helps us decide what to prioritize.
Two: Build a Nutrient-Rich Plate
Supplements are meant to complement, not replace, a nutrient-dense way of eating. We look at how to bring more whole, colorful, minimally processed foods onto your plate. This might include:
- More leafy greens, beans, and root vegetables for potassium and magnesium
- Regular servings of fatty fish or algae-based omega-3 sources
- Quality proteins and healthy fats to keep blood sugar steady
These changes support your whole body, not just your brain.
Three: Use Targeted Supplements When They Are Truly Helpful
Based on your history, lab results, and goals we may add specific supplements. Examples can include a well-formulated multivitamin, vitamin D to reach an optimal range, omega-3 fats, or magnesium in a form your body tolerates. Dose, timing, and interactions with medications all matter, which is why this step is best done with professional guidance.
Four: Monitor and Adjust Over Time
Nutrient needs can change with age, seasons, stress, medications, and life events. Periodic follow-up allows us to see what is working, repeat key tests when needed, and adjust doses so that your plan stays effective and safe.
If you’ve found this information helpful, let us know! We love feedback!
TThe Bottom Line
The paradigm is shifting. We’ve moved from blanket dismissals of supplementation to nuanced, evidence-based approaches that recognize both the limitations of modern diets and the power of targeted nutritional interventions.
The COSMOS trials, vitamin D research, omega-3 studies, and decades of nutritional science research have built a compelling case: micronutrients are not optional extras, they are fundamental requirements for optimal brain function and long-term cognitive health.
The epidemic of nutrient insufficiencies is real, widespread, and consequential. But unlike many health challenges we face, this one has straightforward, accessible solutions.
The question isn’t whether these nutrients matter, science has answered that definitively. The question is whether you’ll take the steps necessary to optimize your own nutritional status, or whether you’ll assume you’re in the lucky 4% getting adequate nutrition from diet alone.
Your brain and your future self will thank you for choosing wisely.
If You Want Support With Your Own Brain Health
If you are curious whether nutrient gaps may be affecting your brain, mood, or energy, you do not have to sort it out alone.
You are welcome to request a visit so we can review your history, consider appropriate testing, and design a personalized nutrition and supplement plan that fits your real life
“You only get one brain and nourishing it well is one of the most meaningful investments in the quality of your future life.”
References
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About the Author
Dr. Erica Oberg is a naturopathic physician specializing in integrative and functional medicine with a focus on brain health, metabolic optimization, and evidence-based natural therapeutics. She combines rigorous scientific research with personalized clinical care to help patients achieve optimal health and cognitive vitality.
Video Source: These 3 Nutrient Deficiencies Are Damaging Your Brain (here’s how to fix it)
This article is for educational purposes and is not intended as medical advice. Individual nutritional needs vary significantly, and any supplementation protocol should be undertaken with professional guidance, particularly for those with existing health conditions or taking medications. Always consult with a qualified healthcare provider before making changes to your supplement regimen.
