Do These Plant Nutrients Slow Brain Aging?

Source: Austin Perlmutter/DALL-E/OpenAI

As our bodies age, our brains age too. This isn’t necessarily bad, as we gain wisdom and experience with the passing years. However, research shows that time can take a substantial toll on various aspects of our brain function. For example, older adults are at higher risk of depression and dramatically higher risk of dementia. However, new research indicates that certain lifestyle choices, including those related to our diets, may help target pathways related to brain aging. In this post, we’re exploring the role of polyphenols, a nutrient group that shows promise.

What is a polyphenol?

For most people, food is seen as comprising calories, macronutrients (fats, carbs, and proteins), and micronutrients (vitamins and minerals). Yet our food also contains an incredible diversity of additional molecules. One group of these molecules now coming into the spotlight is called polyphenols. Polyphenols are molecules found in plant foods as well as (in smaller amounts) animal foods. A wide range of research suggests that the consumption of diverse polyphenol-rich food is a powerful way to support overall and brain health. This is an active area of investigation, with nearly $10 million just committed by the NIH to further study the topic.

How could polyphenols act on the brain?

In understanding how dietary nutrients may influence brain aging, researchers often start by looking at the gut and the gut microbiome. This is especially the case for polyphenols since they are poorly absorbed by our GI tract. Polyphenols are proposed to have several beneficial effects within the gut that could translate into downstream enhancements for the brain. For example, they may help to support the integrity of the gut lining, beneficially influence the species and abundance of bacteria in the gut, and, after being acted on by microbes, turn into metabolites that can be absorbed into the bloodstream and pass through the blood-brain barrier to impact the brain.

How does this relate specifically to brain aging?

Unhealthy brain aging is believed to be driven by a host of pathways including dysregulated inflammatory signaling, vascular dysfunction, altered neuroplasticity, and impaired brain energy production and utilization. Consumption of polyphenols is proposed to act on these pathways, especially by way of beneficially altering the gut microbiome composition. There’s also a recent suggestion that polyphenols may impact longevity-related pathways by way of epigenetic effects, which could have implications for brain longevity. It is notable that most data on this theme comes from preclinical work, with only a few human studies published to date on the topic.

What do we know now?

In general, the strongest evidence for diet as it relates to protecting the brain from unhealthy aging comes from research showing that consuming a minimally processed, whole-food-based diet along the lines of the Mediterranean or MIND diet can help prevent age-related cognitive decline and dementia. These diets feature a wide range of polyphenol-rich foods, including olive oil, fruits, vegetables, nuts and seeds, herbs and spices, and tea, along with healthy fats and fiber.