EXPERT COLUMN
Every night, while you sleep, your brain does something remarkable. It cleans itself. A network of fluid pathways — called the glymphatic system — flushes out metabolic waste products that accumulate during the day, including proteins linked to brain disease — the same harmful proteins most strongly associated with Alzheimer’s disease. When that process is disrupted — by poor sleep, sleep apnea, or chronic insomnia — those proteins build up. Over the years, that buildup accelerates the biological processes underlying dementia. In January 2026, a randomized trial published in Nature Communications confirmed it in humans for the first time.
Most people think of sleep simply as rest, but science now tells us it is something more specific: a biological maintenance cycle the brain depends on to stay healthy. And it is one of the most modifiable factors we have. If you have been putting off a sleep evaluation, the neuroscience now says: do not wait.
The Biggest Threats to Your Brain Have Nothing to Do with Memory
The risk factors most strongly associated with dementia are, perhaps surprisingly, cardiovascular. High blood pressure, high cholesterol, diabetes, obesity, and physical inactivity damage the brain’s blood supply and accelerate neurodegeneration — not just the heart. Research at academic institutions has established these associations as clearly as almost any finding in medicine. Managing them is brain health.
Untreated hearing loss belongs on that list — it is one of the most underappreciated risk factors for cognitive decline, likely because it reduces cognitive stimulation and social engagement over time. So does chronic social isolation. These are findings from large longitudinal studies, and they point to something important: many of the factors that drive dementia are modifiable, and many of them are already on your physician’s radar for other reasons.
What Ozempic, Mounjaro and Similar Medications May Mean for the Brain
Some of the most widely prescribed medications today — including semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) — are synthetic versions of a hormone the body produces naturally after eating. That hormone starts in the gut but travels to the brain, where it signals fullness and reduces hunger. Because it already crosses that gut-to-brain pathway, researchers are now studying its potential effects on the very brain processes that drive neurodegeneration. A 2025 study published in JAMA Neurology found these medications were associated with meaningfully reduced rates of Alzheimer’s disease and related dementias in people with type 2 diabetes.
The strongest evidence to date is for semaglutide specifically. Multiple large real-world studies found it associated — a strong correlation, not a proven cause — with a 40 to 70 percent reduced risk of developing Alzheimer’s compared to other diabetes medications. Researchers have proposed several mechanisms — reduced brain inflammation, improved insulin sensitivity, better blood sugar control, and enhanced clearance of toxic proteins. Tirzepatide, which activates an additional receptor pathway, shows similar biological promise. Those retrospective studies could not prove the medications were the direct cause — only that there appeared to be a connection.
To answer that harder question, researchers turned to prospective clinical trials. The EVOKE and EVOKE+ studies — the largest ever conducted on this specific question, involving nearly 4,000 participants — were designed to determine whether semaglutide could slow the progression of Alzheimer’s disease. Their results, reported in late 2025, were sobering: it could not. Reducing the risk of developing a disease and treating it once it is established are very different things.
If you take a medication in this class, it is worth raising this research with your physician. The evidence is promising, not conclusive — and that conversation is exactly the kind academic medicine is built to support.
That work is happening locally in South Florida. The David and Lynn Nicholson Center for Neurodegenerative Disease Research at Florida Atlantic University’s Schmidt College of Medicine, in partnership with the Marcus Neuroscience Institute at Boca Raton Regional Hospital, is among the institutions pursuing it.
In the next column, we will turn to a topic that affects more people in South Florida than most realize, and that rarely gets discussed honestly: addiction. What it actually looks like in adults, why it is so frequently overlooked, and what to do about it.
Lewis S. Nelson, MD, MBA, is Dean and Chief of Health Affairs at Florida Atlantic University’s Charles E. Schmidt College of Medicine, the only medical school in Palm Beach County. He is a nationally recognized expert in medical toxicology and a co-editor of Goldfrank’s Toxicologic Emergencies, the definitive reference in the field.
