Building a Brain That Ages Well

“Genetics loads the gun, but environment pulls the trigger.”

I think this phrase captures an important, hopeful concept: our genes are not necessarily our destiny, and we can somewhat influence how our health plays out.

We inherit genetic variations that can increase our susceptibility to certain diseases. But what happens over the course of our lives—including how we eat, breathe, move, sleep, manage stress and connect with others—can influence how those risks play out.

This idea has become particularly interesting to me as I've been reading about the latest research on Parkinson's disease and Alzheimer's disease, as presented by neurologist Dr. David Perlmutter in his podcasts and newsletters.

• Perlmutter is one of the world’s leading Alzheimer’s and Parkinsons experts and argues that both of these neurological diseases may be preventable in some cases.  

Both diseases have traditionally been thought of primarily as disorders of the brain. But scientists are learning that the story may begin much earlier—and may involve the health of our gut, immune system, metabolism and environment as much as the brain itself.

Parkinson's: The Gut May Tell the Story First

One of the most fascinating recent developments is the growing evidence connecting the gut microbiome with Parkinson's disease.

• A 2026 study published in Nature Medicine looked at the gut microbiomes of people with Parkinson's, healthy individuals and people carrying a variant of the GBA1 gene, the strongest known genetic risk factor for Parkinson's disease.

  
  

• Here's what was particularly interesting: researchers found that approximately one-quarter of the gut microbiome showed Parkinson's-like changes not only in people with the disease, but also in some people who carried the genetic risk but had not yet developed Parkinson's. These microbiome changes were also associated with symptoms that can precede the classic movement problems of Parkinson's.

  
  

• Even more intriguing, similar microbiome patterns were found in some otherwise healthy people without a known genetic risk.

In other words, changes in the gut may be detectable before Parkinson's becomes clinically obvious.

This doesn't mean that an altered gut microbiome causes Parkinson's. The study was not designed to prove cause and effect, and researchers say that long-term studies are needed to determine whether people with these microbiome patterns actually go on to develop the disease. It does, however, give us another reason to pay attention to our gut health.

What does this have to do with what we eat?

Researchers found reductions in several bacteria that produce butyrate, a short-chain fatty acid created when certain gut bacteria ferment dietary fiber. Butyrate is involved in maintaining the intestinal barrier and regulating immune and inflammatory processes.

That brings us right back to the basics:

Eat the plants.

• Vegetables

• Fruit

• Beans and lentils

• Whole grains

• Nuts and seeds

• A variety of fiber-rich foods

  
  

We're not eating these foods only for vitamins, minerals and fiber. We're also feeding the trillions of microorganisms living in our gut. Researchers are increasingly interested in how those microorganisms communicate with our immune system and, ultimately, our brain.

It's Not All About Genetics

The Parkinson's research also makes me think about another fascinating conversation on another Perlmutter podcast with neurologist Dr. Ray Dorsey.

• Dorsey challenges the idea that Parkinson's is primarily a genetic disease. He points to the PD GENEration study, in which approximately 87% of participants did not have an identified genetic cause or risk factor. 

  
  

• Importantly, this statistic does not mean that 87% of Parkinson's cases are proven to be caused by environmental toxins. Rather, it highlights the likelihood that factors beyond our genes play an important role.

Dorsey discusses research linking Parkinson's risk with environmental exposures including certain pesticides, solvents and air pollution. 

We obviously can't control everything in our environment. But we can make reasonable choices to reduce unnecessary exposures.

• Buy organic produce when we can

• Wash all produce before eating

• Avoiding dry cleaning or choose “Green” cleaners

• Investing in a room air filter for living spaces or bedrooms

• Spending less time on golf courses and sports fields where herbicides and other chemicals are used

Again, this isn't about becoming fearful of everything around us. It's about recognizing that our environment is part of our biology.

Alzheimer's May Begin Decades Before We Notice It

The same idea of "starting earlier" applies to Alzheimer's disease.

One of the most striking points from neurologist Dr. Jonathan Fellows, also featured on Perlmutter's podcast, is that Alzheimer's disease may be developing biologically 20–30 years before noticeable symptoms appear. 

Think about that. If we're in our 40s, 50s or 60s, we may think we're much too young to worry about Alzheimer's. But perhaps we're actually in one of the most important windows for building the foundation for future brain health.

• New research makes this timeline even more fascinating. Researchers are studying p-tau217, a blood biomarker associated with Alzheimer's pathology. In a 2026 NIH-highlighted study, people with elevated p-tau217 at age 60 developed Alzheimer's symptoms, on average, about 20 years later. Those whose levels became elevated at age 80 developed symptoms approximately 11 years later.

• This does not mean that a blood test can currently tell an individual exactly when Alzheimer's will begin. The researchers emphasize that the models aren't yet accurate enough for individual clinical prediction, and p-tau217 isn't recommended as a stand-alone test for cognitively healthy people.

  
  

The research reinforces a fascinating concept: The Alzheimer's story may begin long before the memory problems do.

So What Can We Do About It?

This is where I find the research encouraging rather than frightening. We can't choose our genes. We can't eliminate every environmental exposure. There is certainly no diet, supplement or exercise program that guarantees we won't develop Alzheimer's or Parkinson's. But there is considerable evidence that many of the factors associated with healthy aging are also associated with healthier brain aging, and there ARE things we can DO to help our brains age more healthfully.

• The 2024 Lancet Commission identified 14 potentially modifiable (i.e. we have some control!) risk factors for dementia, including physical inactivity, diabetes, hypertension, obesity, hearing loss, smoking, excessive alcohol consumption, social isolation, air pollution, high LDL cholesterol, untreated vision loss, depression and traumatic brain injury. The Commission estimated that addressing these factors could potentially prevent or delay a substantial proportion of dementia cases worldwide.

That is a powerful message, focused not on perfection, but on prevention and resilience.

Eat for Your Gut—and Your Brain

Focus on dietary patterns rather than individual "superfoods."

Think:

• Plenty of plants and fiber

• A variety of colorful vegetables and fruits

• Beans and legumes

• Nuts and seeds

• Whole grains

• Adequate protein

• Minimally processed foods

• Healthy fats, including those from fish, nuts and olive oil

The goal is to create a nutritional environment that supports metabolic health, cardiovascular health and a diverse gut microbiome.

Move Your Body

This one is certainly not new, but I think we're beginning to appreciate just how important movement is for healthy aging. Exercise supports cardiovascular and metabolic health, helps maintain muscle, improves sleep and can benefit mood and cognitive health.  This is why I continue to be such a fan of strength training.

Building muscle isn't simply about looking strong. It's about maintaining the physical capacity to live independently as we age—and supporting the metabolic health that helps support the brain.

• Walk

• Lift weights

• Practice yoga

• Do Pilates

• Take a fitness class

• Garden

• Dance

  
  

Move throughout the day. Your brain benefits from an active body.

Protect Your Sleep

Sleep isn't simply downtime. It's an important part of the body's recovery and maintenance processes, and poor sleep is increasingly recognized as relevant to brain and metabolic health.

Midlife sleep can be challenging—especially when hormones, stress and busy lives get in the way. But creating consistent sleep routines, getting morning light, exercising regularly and finding ways to calm the nervous system are all worthwhile investments.

Don't Underestimate Your Social Life

Here's one that can easily get overlooked when we talk about nutrition and exercise: connection matters.

The Lancet Commission includes infrequent social contact among potentially modifiable dementia risk factors.

• Call a friend.

• Join a book club.

• Take a yoga class.

• Have dinner with people you enjoy.

• Volunteer.

• Keep learning.

Our brains weren't designed to live in isolation.

We Don't Get to Choose Our Genes. But We Have Choices.

The more I learn about healthy aging, the more I appreciate that it isn't about finding one magic solution. It's about stacking small, healthy choices over many years.

• The food we eat.

• The air we breathe.

• How often we move.

• Whether we maintain our strength.

• How well we sleep.

• How we manage stress.

• Whether we stay socially connected.

• How we care for our metabolic and cardiovascular health.

  
  

None of these guarantees that we will avoid Alzheimer's or Parkinson's. But they are all pieces of a much larger picture of healthy aging and resilience.

Genetics may load the gun, but our environment and lifestyle help determine how the story unfolds.

That is exactly why I don't think midlife is too early to start thinking about brain health. We're not simply trying to prevent disease. We're building the body—and the brain—we want to live in for many years to come.