For Brain and Belly? New Science on GLP-1 for Alzheimer's

Could a hormone made famous by drugs like Ozempic secretly help defend your brain against Alzheimer's disease? New research that actually surprised me looks very encouraging. Let's just get right into it. Take a look at this graph. This represents the relationship between the hormone GLP-1 circulating in the blood and levels of amyloid in the human brain. GLP-1 is that now famous weight loss hormone that drugs like Ozempic and Wegovy try to mimic, and amyloid is a pathological hallmark of Alzheimer's disease. And you can see very clearly an inverse relationship: lower GLP-1 levels associate with more amyloid, and higher GLP-1 levels associate with less amyloid. Now, let's take a look at these brain images, these brain scans that reinforce the point. More yellow and red tones indicate more amyloid, whereas more green and blue tones suggest less amyloid. In the brain on the left is the scan from the patient, on the graph, with the lowest GLP-1 levels. In the brain on the right is the scan from the patient with the highest GLP-1 levels. Unmistakably, there is more amyloid in the brain with lower GLP-1 levels, and vice versa. There is unmistakably an inverse relationship between GLP-1 and amyloid. Isn't that interesting? Now, let's delve deeper into these new data and explain why this pattern exists mechanistically and what it might mean for your brain health. Now, these new data come from a paper in Nature Aging, in which researchers set out to study the mechanism by which GLP-1 hormone and GLP-1 receptor agonists, medications like Ozempic and Wegovy, as well as newer generation combination agonists like Tirzepatide, might protect against Alzheimer's disease in a direct manner, so not just through weight weight loss. Now, there are already promising signals in the human data, I just want to be clear, including results from a large Danish registry-based cohort study of 120,054 participants with diabetes. This showed 11% lower rates of dementia among those treated with the GLP-1 receptor agonists. And this is also consistent with other randomized controlled human trials, including those targeting cardiovascular outcomes and a 12-month phase 2 randomized controlled trial in adults with mild cognitive impairment. But the evidence is early and the mechanisms are still murky, so the researchers behind this new Nature Aging paper, in very technical terms, asked, "Well, what's up, doc?" And after observing this inverse association between GLP-1 and amyloid levels in both human and mouse brains with Alzheimer's disease, they conducted a set of carefully controlled mechanistic experiments that decoded the following fascinating pathway. Ready? GLP-1 hormone, or GLP-1 receptor agonists, bind to receptors in the brain. This flips on a crucial metabolic switch called AMPK. AMPK then shuts down a pro-inflammatory complex called NF-kappa-B. This reduces inflammation in the brain. It reduces neuroinflammation. And with neuroinflammation down, the brain's immune cells, called microglia, they become better at gobbling up amyloid and clearing out debris out of the brain. And maybe most importantly, AMPK getting turned on suppresses an enzyme called BACE1. This is the enzyme that starts the whole amyloid production process. BACE1 is critical in making amyloid oligomers that mark and are thought to contribute to the pathological cascade of Alzheimer's disease, like the worst domino chain you can imagine. Specifically, BACE1 is the enzyme that initially chops the amyloid precursor protein into a form that then undergoes subsequent processing into the neurotoxic amyloid beta-40 and amyloid beta-42 oligomers. Now, I did want to show you this summative figure from the paper, but I realize it's pretty intimidating, so here's the keep it simple stupid version. GLP-1 and GLP-1 receptor agonists, they decrease neuroinflammation, they improve amyloid clearance, and GLP-1 decreases amyloid production by inhibiting that key enzyme, BACE1. And if that still didn't stick, here's an analogy to hopefully make it stick. If toxic amyloid were cupcakes, BACE1 is the cupcake tin. Without BACE1, there are no amyloid cupcakes. Does that stick? Let me know in the comments. Anyway, does this actually help brain function? It appears so. So, in mice predisposed to Alzheimer's disease, one group was given GLP-1 receptor agonists for 8 weeks versus a control group. In the mice with the GLP-1 receptor agonist treatment, they showed activation of AMPK, lower levels of amyloid, a reduction in amyloid plaques in the brain by about half, which is impressive, and importantly, improved performance on memory tests. This aligns with the human data on GLP-1 receptor agonists in Alzheimer's disease and presents the exciting possibility that interventions, drugs or otherwise, that increase GLP-1 could prevent one of the world's most debilitating diseases, one that has plagued patients, families, doctors, scientists, and quite honestly the economy alike. And maybe this shouldn't be a surprise at all. Irrespective of your opinion and position on modern medical obsession with GLP-1 receptor agonists, these data are consistent with a broader truth. The brain is a metabolic organ, and whether we're talking about neurodegenerative diseases like Alzheimer's or Parkinson's disease—see this video for more on that—or mental health, we can fix the problem by addressing the root cause: metabolic health. These data, they're fascinating. But I think we all want more. Here's what I'm personally left wondering. First, if there are anti-Alzheimer's benefits of GLP-1 receptor agonists, what is the minimum effective dose? Two, when should GLP-1 receptor agonists be started, if at all, for Alzheimer's prevention in at-risk patients? 3. For patients without overweight or obesity, say like me, would microdosing be effective at preventing Alzheimer's disease? And 4. What is the interaction, if any, with common risk variants for Alzheimer's disease like the APOE4 risk allele? Would APOE4 carriers benefit more or less from GLP-1 treatment or GLP-1 microdosing? Now, wrapping up, I just want to clarify this video isn't advocating that you commence a GLP-1 receptor agonist today. I'm just sharing data non-dogmatically to help you make informed choices. But at the end of the day, the goal is to improve brain metabolism and reduce Alzheimer's disease risk. So now in closing, here are some rapid-fire suggestions and more resources that you can access and use today. First, ketosis. In addition to providing an efficient fuel for the brain in the form of ketogenic bodies, a ketogenic diet or intermittent fasting can trigger ketosis, and this can help clean up the brain, clearing debris out of the brain. If you want more, see this video. Next tip: coffee and yerba mate. This is great news for coffee lovers. A health-promoting compound found in coffee and yerba mate tea called chlorogenic acid can activate a signaling pathway called the NRF2 pathway in the brain that can reduce neuroinflammation and support brain health. For more on this and its relation to heart health, you can see this video. Third, red light therapy or photobiomodulation. This can alter mitochondrial function in the muscles and in the brain. There are data including human randomized controlled trials suggesting this could help improve cognition. For more, see this video. Fourth, and I can't miss this one, exercise. Regular cardiovascular and resistance training is really important for brain health. Never forget, your muscles are endocrine organs, meaning they secrete hormones like your thyroid or your adrenals. One example is the hormone erisin, which signals to the brain to increase levels of the neuroprotective factor BDNF. So next time you're lifting, remember this: you're spotting your future brain health. And for more on that, see this video. And finally, to round out our 5, Sleep. Sorry to beat a dead horse on this one, but sleep is critical for activating the glymphatic system to clear debris out of your brain. And for more on that and how the glymphatic system actually works, see this video with input from an Oxford expert on the topic. So, can a popular weight loss drug protect your brain? The science is still early, but it's really promising. But as with all things in medicine, the real story isn't about just one molecule. It's about how all the systems of your body—metabolic, immune, neurological—they're deeply intertwined. What I want you to really take away from this video is not a medication prescription, but an appreciation there is more overlap in metabolic diseases and disease processes than our current medical models and medical system seem to appreciate. Everything's so siloed, and quite honestly, that's not appropriate and it's not serving patients. Right now, GLP-1 drugs are tools to be used in the right patients. But these data highlight something bigger. Brain health starts with metabolic health. Do you agree? Tell me, and stay curious. Thanks so much.