Can Your Diet Help Prevent Alzheimer’s?

Source: Austin Perlmutter/DALL-E

Alzheimer's disease, a progressive neurodegenerative disorder, affects about 7 million people in the U.S. and many more worldwide, leading to cognitive decline, lower quality of life, and even early death. While genetics and age are significant risk factors, recent research suggests that diet plays a crucial role in either exacerbating or mitigating the risk of developing Alzheimer's. This article delves into the latest findings, exploring how dietary choices can help prevent Alzheimer's disease.

What Causes Alzheimer’s and How Does Diet Relate?

Historically, Alzheimer’s disease has been pinned on a buildup of proteins like amyloid beta and tau, processes over which we had minimal control. In recent years, we’ve seen several major challenges to this model.

First, an investigation into some of the key research on amyloid revealed evidence that results had been fabricated. Perhaps more importantly, a growing body of research has shown that processes like inflammation, metabolism, and neuroplasticity seem to be directly involved in the risk of developing the disease and its progression.

This turn in perspective becomes incredibly relevant in the context of lifestyle medicine, as we know that our choices, and especially our diet, play a major role in each of these pathways. Data recently published in The Lancet suggest that 40 percent of dementia cases are preventable (Alzheimer’s is the most common cause)—but with the growing understanding of how our choices, including diet, impact this disease, this number is likely to grow considerably.

What is the Best Diet for Preventing Alzheimer’s Disease?

It’s easy to debate the pros and cons of every fad diet as it relates to an individual disease. The reality, as it relates to Alzheimer’s, is that the data are quite clear on what an optimal diet looks like.

Here, research confirms that a minimally processed diet rich in healthy fats, proteins, fiber, and plant nutrients is at the top of the list. This diet is best characterized as the “Mediterranean” diet, or, to a somewhat lesser degree, the “MIND” diet (Mediterranean-DASH Intervention for Neurodegenerative Delay—a somewhat more plant-based version of the Mediterranean diet).

A 2024 meta-analysis on the Mediterranean diet that looked at over 65,000 people found an overall decreased risk for dementia in those adhering more closely to the diet, with a 27 percent decrease in odds of getting Alzheimer’s in a subset of about 38,000 people. A 2023 review of three cohort studies using the MIND diet found a 17 percent decreased rate of dementia in those with the highest adherence. Of note, while the dataset is much smaller, recent research does suggest a potential benefit of a low carbohydrate (keto) diet in those who have Alzheimer’s dementia.

What Foods and Nutrients are Most Important in Fighting Alzheimer's?

Polyphenols: Nature's Brain Protectors

Polyphenols, a category of antioxidants found abundantly in plant-based foods, have garnered attention for their neuroprotective properties, and appear to act on metabolic, immune, and neuroplastic pathways. As described in a 2025 article in The Journal of Prevention of Alzheimer's Disease, phytochemicals like polyphenols may present a potential therapeutic strategy for the condition and could “provide the possibility to solve several issues with standard anti-Alzheimer’s Disease medications.” In a 2023 systematic review of 37 studies, it was found that people who consumed the highest amount of certain polyphenol families were over 20 percent less likely to develop cognitive decline.

Polyphenols are naturally found in plant foods, especially colorful fruits and vegetables. They’re also concentrated in coffee, tea, red wine, and especially in spices.

Modern processed food tends to be lower in healthy polyphenols, which is more reason to prioritize eating minimally processed food when possible. Bland foods like industrially produced wheat are usually lower in these brain-boosting nutrients, while bitter foods (like Tartary buckwheat) can have over a hundred-fold higher concentration. Choosing more diverse and less processed plant foods is an overall excellent strategy to enhance polyphenol intake.

Healthy Fats: A Booster for Cognitive Protection

Though they’ve been villanized for some time, fats may be among the most important protective nutrients for brain health. In particular, fatty foods that are rich in unsaturated fats like omega-3s appear to have an outsized benefit to the brain. Some of the best-studied sources of brain-boosting fats include fatty fish, extra-virgin olive oil, and nuts

In a 2024 meta-analysis of 35 studies, those who consumed the most fish were found to have an 18 percent lower risk for developing cognitive impairment, and a 20 percent lower risk for Alzheimer’s disease, with cognitive benefits continuing to grow up to 150 grams of fish per day. Similarly, olive oil consumption (which increases the intake of healthy fats as well as polyphenols) has been linked to brain benefits. As stated in a 2024 review, “consumption of olive oil is associated with cognitive benefits and a decreased risk of Alzheimer’s disease and related dementias… [extra-virgin olive oil] and its phenolic compounds hold promising potential for the prevention and treatment of Alzheimer’s disease.”

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Incorporating nuts into one's diet may also offer protective benefits against Alzheimer's disease (although the data have been a bit more mixed). One compelling study published in Geroscience in 2024 examined the relationship between nut consumption and dementia risk among over 50,000 UK adults. The findings revealed that individuals who consumed a handful of nuts daily had a 12 percent lower risk of developing dementia. The protective effect was even more pronounced among those who consumed unsalted nuts.

Conclusion

Emerging research underscores the significant impact of dietary choices on the risk and progression of Alzheimer's disease. Diets rich in plant-based foods, healthy fats, and antioxidants—such as the Mediterranean and MIND diets—have been associated with a reduced risk of cognitive decline. Incorporating specific foods like olive oil, fish and nuts may further bolster brain health.

While these findings are promising, it's essential to approach dietary changes as part of a holistic lifestyle strategy, including regular physical activity and mental engagement, to support cognitive function. As always, individuals should consult healthcare professionals before making significant dietary adjustments, especially those with existing health conditions or dietary restrictions.