Many people notice small lapses as they get older, forgetting why they walked into a room, or pausing mid-sentence while searching for a word. For most people, these moments are simply the effect of a busy, overloaded life, not a sign of early cognitive decline. Even so, it is worth taking notice, because the choices made in midlife have a real, measurable effect on long-term brain health.
A major 2024 report from the Lancet Commission found that about 45% of dementia cases worldwide are tied to modifiable risk factors, not genetics or chance. This figure points to an encouraging conclusion: a large share of cognitive decline may be preventable through choices made well before symptoms appear.
There are five foundational lifestyle areas that consistently show up in the research: nutrition, movement, sleep, social connection, and chronic stress.
Nutrition and Brain Function
The brain runs on steady glucose for fuel. When blood sugar spikes and crashes again and again, over years, it affects the same insulin pathways the brain depends on to function well. This is part of why some researchers now describe Alzheimer’s disease as having a metabolic component, closely tied to insulin resistance in the brain itself. When neurons cannot use fuel efficiently, cognitive function suffers. A diet heavy in processed carbohydrates and frequent snacking makes that efficient fuel use harder to sustain.
Consistency and quality of meals is key. A plate built around protein, healthy fat, and fiber at each meal supports steadier blood sugar than a diet built around convenience foods with refined carbohydrates and added sugars. Whole, minimally processed foods supply the nutrients the brain needs.
Where to start
- Build meals around a source of protein and healthy fat, rather than starting with refined carbohydrates.
- Prioritize fatty fish, walnuts, and flaxseed for omega-3 fatty acids, which form part of the structure of brain cell membranes.
- Include a wide range of colorful vegetables and berries, which help offset the oxidative stress that builds up with age.
- Notice how you feel a couple of hours after eating. Fatigue or mental fog afterward is useful information about how well that meal supported steady blood sugar.
Movement and Cognitive Resilience
Physical activity offers the brain benefits that are hard to get any other way. Exercise increases blood flow to the brain and stimulates production of brain-derived neurotrophic factor (BDNF), a protein that supports the growth and survival of neurons. This connection between movement and brain health is one of the more well-established findings in the research.
The benefit of physical activity does not require intense or lengthy workouts. The research points to consistency over intensity. A mix of aerobic activity, which raises heart rate, and resistance training, which supports muscle and metabolic health, appears to offer the most complete protection. Yoga and other mindful movement practices add something else: they support coordination and help regulate the nervous system, both of which matter for brain health over time.
Where to start
- Aim for movement on most days, even if that means a twenty-minute walk rather than a structured workout.
- Add resistance training two to three times a week, which also supports healthy blood sugar regulation.
- Choose activities that are sustainable. The most beneficial exercise for the brain is the one a person will keep doing.
Sleep and the Brain’s Cleanup System
Sleep is not a passive state for the brain. During deep sleep, the brain relies on what researchers call the glymphatic system to clear away metabolic waste, including amyloid-beta and tau, two proteins strongly linked to Alzheimer’s disease. This waste-clearance process is far more active during deep, slow-wave sleep than during wakefulness, which is one reason sleep quality, not just sleep duration, plays such a significant role in long-term brain health. As people age, this deep sleep stage naturally becomes shorter and harder to sustain, which may partly explain why sleep disruption and cognitive decline so often appear together.
Where to start
- Aim for consistent sleep and wake times, even on weekends, to support the body’s natural rhythm.
- Keep the bedroom dark, cool, and quiet, all of which support deeper sleep stages.
- Limit screens in the hour before bed, since light exposure late in the evening can delay the onset of deep sleep.
Social Connection as a Protective Factor
Social connection is easy to overlook in conversations about brain health, yet the research is compelling. Strong social ties are consistently linked to a lower risk of cognitive decline, and social isolation is recognized as one of the established modifiable risk factors for dementia. Meaningful connection tends to support a parasympathetic, rest-and-digest state in the body, while isolation and loneliness keep the stress response switched on for longer stretches.
Where to start
- Prioritize time with people who feel supportive and easy to be around, not just relationships kept out of habit.
- Consider one small, recurring commitment, such as a class, a walking group, or a regular gathering, that gives you something to look forward to.
- Notice the difference between social time that drains you and social time that fills you back up. Both count as connection, but they do not offer the same benefit.
Chronic Stress and the Brain
Stress hormones, particularly cortisol, are designed for short-term use. In a real emergency, cortisol signals the liver to release glucose into the bloodstream and temporarily reduces the body’s sensitivity to insulin, making more fuel available for a quick response. This is a useful, protective system when it turns on and off as intended.
The trouble comes when it does not turn off. When cortisol stays elevated over weeks, months, or years, that same glucose-releasing, insulin-blunting effect becomes a chronic burden rather than a short-term boost, contributing to blood sugar instability. Sustained cortisol exposure has also been linked to measurable changes in the hippocampus, the part of the brain responsible for memory, including reduced volume over time. In other words, chronic stress does not just affect mood. It has a direct, physical effect on the brain.
Where to start
- Build in small, regular moments of genuine rest. Not just time off, but time in a parasympathetic state: slow breathing, time in nature, or quiet unstructured time.
- Pay attention to your own early signs of chronic stress, whether that shows up as sleep trouble, digestive changes, or simply feeling wired but tired, and treat those signs as useful information rather than something to push through.
- Consider working with a therapist, counselor, or other support if stress feels difficult to manage on your own. This is not a sign of weakness. It is often one of the most effective ways to lower the body’s baseline stress load.
Supplements With Research Support
A few supplements have evidence behind them for brain health, though none should be viewed as a replacement for the foundational habits above.
Omega-3 fatty acids and B vitamins together
A study in older adults with mild cognitive impairment found that B vitamin supplementation (folic acid, B6, and B12) to lower homocysteine, an amino acid linked to brain atrophy, slowed both brain shrinkage and cognitive decline. Importantly, this benefit only showed up in participants who also had adequate omega-3 levels.
Daily Multivitamin
In a controlled trial in older adults, daily multivitamin-mineral supplementation was associated with meaningfully better memory and cognitive test scores over three years compared to placebo.
Probiotics
The gut and brain communicate closely, so it makes sense that supporting gut bacteria directly might support cognitive function, and the research is starting to back this up. A 2025 meta-analysis found that probiotic supplementation significantly improved cognitive function in people with mild cognitive impairment or Alzheimer’s disease. Probiotics can also be found in probiotic foods such as fermented vegetables, yogurt, and kefir.
Foundations of Brain Health
These practices are foundational to brain health. People who are already eating whole foods most of the time, moving regularly, sleeping well, managing their stress, and maintaining a few meaningful relationships are already doing a great deal to support their brain health.
It may help to consider which of these areas feels least supported right now, and start there. Sustainable change tends to come from one deliberate adjustment at a time, rather than attempting everything at once.
At Radiance Functional Medicine, we offer functional medicine and nutrition counseling. We hope that you will allow us to help you heal your gut, balance your hormones, or find a way of eating that helps you thrive. Schedule an appointment to get started. Whether you are looking for a nutritionist or functional medicine doctor in Denver or your local area, we see patients in person and virtually. Call our office at 303.333.1668 to schedule your Initial Consultation.
