Can You Eat To Prevent Alzheimer's? This MD Thinks So — Here's How

If you think of Alzheimer's as an inevitable fate—or believe cognitive decline is just what happens with age—Dale Bredesen, M.D., would urge you to think again. 

The neurologist and bestselling author has spent decades studying Alzheimer's and cognitive impairment, and he insists we have more power over our brain health than we realize. In a recent episode of the mindbodygreen podcast, Bredesen laid out a strikingly simple framework: seven basics, two specifics. One of the most powerful levers? Diet.

But not just any diet. We're talking about a plant-rich, mildly ketogenic diet high in fiber, phytonutrients, and detoxicants—an approach he says can literally "change the brain from downsizing due to energy deficits to thriving with renewed neuroplasticity." 

Alzheimer's isn't just about memory loss—it's about energy. "The brain begins to lose the ability to metabolize glucose efficiently," Bredesen explains. Ketones, by contrast, offer a cleaner, more efficient fuel. 

Enter: the ketogenic diet.

While full-blown keto might be hard to sustain, a mildly ketogenic approach—high in healthy fats and plant-forward meals but low in refined carbs—can nudge the brain into a state of nutritional ketosis. Studies show this shift may improve mental clarity, mood, and memory in patients with Alzheimer's.

A 2024 meta-analysis of 10 randomized controlled trials1 found that ketogenic diets significantly improved cognitive function in Alzheimer's patients, with noticeable gains on standard scales like MMSE and ADAS-Cog. 

We've long known fiber keeps digestion humming—but now, science is uncovering its powerful influence on the brain. Bredesen emphasizes that optimizing your gut microbiome is a core part of protecting your cognition.

Here's how it works: Dietary fiber feeds beneficial gut microbes, which in turn produce short-chain fatty acids like butyrate—compounds that reduce inflammation, protect the blood-brain barrier, and support the gut-brain axis. These microbial metabolites interact with the brain via the vagus nerve, immune signaling, and neurotransmitter production.

Phytonutrients—those colorful compounds found in plants—don't just fight free radicals; they actively support brain function. Cruciferous vegetables like broccoli, kale, and cauliflower, for example, are packed with sulforaphane, a compound shown to activate detoxification pathways and reduce neuroinflammation.

And it turns out, a high-antioxidant, plant-forward diet may complement the effects of ketosis. While ketosis fuels the brain, phytonutrients protect it—decreasing oxidative stress, supporting vascular health, and stimulating the release of brain-derived neurotrophic factor (BDNF), a key player in learning and memory.