Nutrition for Brain Health: A Functional Medicine Approach

A guest post by Dr. Sarah Khan, PhD

Most people think about brain health the way they think about retirement: important, but a problem for later. The research points in a different direction. The metabolic, inflammatory, and nutritional conditions that shape how your brain performs at 70 are being set in earlier decades, as early as your 20s, 30s, and beyond, and often well before that.

That is genuinely good news, because nutrition for brain health is one of the few levers you can pull every single day. It is not a single supplement or a single superfood. It is a set of overlapping strategies that address how the brain gets fuel, how it handles oxidative stress, how much inflammation it is exposed to, and whether it has the raw materials to build neurotransmitters and maintain myelin.

The Functional Medicine Lens: Why This Starts Upstream

Conventional cognitive care tends to ask whether symptoms have crossed a diagnostic threshold. A functional medicine approach first asks a different question: what upstream drivers might be accelerating decline, and which are modifiable right now?

That framing is not a rejection of neurology. It works alongside it. The Institute for Functional Medicine describes the model as one that treats modifiable lifestyle factors, nutrition chief among them, as central to identifying the underlying contributors to clinical imbalance rather than as an afterthought. Applied to the brain, that means looking at metabolic health, gut function, immune activation, nutrient status, sleep, and stress physiology as a connected system rather than as separate specialties.

There is now solid trial evidence that the multidomain version of this approach works.

Build Your Plate Around Whole, Minimally Processed Foods

If you make one change, make this one. It is basic and simple, and it outperforms almost everything else.

The evidence on ultra-processed foods and cognition is hard to ignore. In a 2026 Harvard analysis of 5,370 older adults followed for nearly nine years, participants eating the most ultra-processed food had a 58% higher risk of developing dementia than those eating the least, plus a 46% higher risk of cognitive impairment short of dementia. The same study found the opposite: participants who ate the most whole, minimally processed foods had a 41% lower risk of dementia.

Ultra-processed products tend to be high in refined sugars, refined oils, and sodium while being low in fiber, vitamins, minerals, and bioactive plant compounds. Ultra-processed intake has also been linked to gut dysbiosis, increased intestinal permeability, and intestinal inflammation, which may extend to neuroinflammation. That combination maps onto the three pathways now recognized as central to neurodegeneration: systemic inflammation, oxidative stress, and metabolic dysregulation.

What this looks like in practice: Eating more foods that come from a plant or an animal, which include vegetables, fruit, legumes, whole grains, nuts, seeds, fish, eggs, poultry, and olive oil. Vegetables and fruit deserve particular emphasis because they are the primary sources of vitamins, minerals, fiber, and phytonutrients discussed above. Aim for volume and diversity rather than perfection.

Support for Living With Chronic Illness

Nutrition is one piece of overall well-being, but living with a chronic health condition can affect much more than your physical health. It can influence your mood, stress levels, relationships, identity, and how you feel in your own body. If you are navigating the emotional impact of an ongoing heal

th condition, learn more on our Chronic Illness Therapy page. If you feel that therapy could be helpful, we invite you to reach out to us.

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About the Author

Dr. Sarah Khan, PhD, MBA, is a functional and integrative nutritionist and the founder of Sarah Integrative and Functional Nutrition, a concierge private practice based in New York City. She holds a PhD in Integrative and Functional Nutrition. Her clinical work centers on gut health, autoimmune disease, including Hashimoto's and other thyroid conditions, and hormonal and metabolic health, using a root-cause, systems-biology approach. She works with clients virtually nationwide.