Dr Thomas HollandThomas M. Holland, MD
Recently published study data from the community-based Memory and Aging Project (MAP) has suggested that a higher dietary intake of flavonols may be associated with a lower risk of developing Alzheimer disease dementia.

The study was conducted by Thomas M. Holland, MD, and colleagues at Rush University, and is currently still ongoing. This dataset included 921 participants, of which 220 developed Alzheimer disease dementia. The dietary intake of several types these phytochemicals was inversely associated with incident Alzheimer dementia.

To find out more about the data and what the takeaways are for the clinician community, NeurologyLive reached out to Holland, inquiring about what they add to our understanding of diet and its impact on dementia.

NeurologyLive: For the physician community, what would the most important takeaway(s) be from these data?

Thomas M. Holland, MD: This is of importance because it adds further confidence to the fact that the foods we are consuming do matter. When we think of foods, we naturally think about the vitamins and minerals contained in those foods. This research lends a further understanding of the contents of the foods we eat. Although very important, it is not just the nutrients in the foods we eat. It is also the bioactives contained in them. The bioactives in foods—which from our research would be specifically flavonols found in kale, spinach, tomatoes, tea, olive oil, apples, pears, and over 20 other foods—have antioxidant and anti-inflammatory properties that have the potential to protect against cellular damage due to oxidative stress and sustained inflammation.

My message would be to eat your fruits and vegetables, particularly dark leafy greens, and drink some tea every now and again. A healthy diet that contains various fruits and vegetables is critical for continued health, especially brain health and is a strong component of a healthy lifestyle. As our knowledge of the pathogenesis of Alzheimer’s dementia expands and we recognize that it is multi-factorial. We should prepare ourselves as best we can with multiple, scientifically-based tools to help stave off the progression with an eye toward the ultimate goal of prevention. Our toolbox should be filled with as many diverse tools as the disease itself.

Although diet is a strong factor, it is one component of a healthy lifestyle. Lifestyle modifications that have been shown to have an association to either delayed cognitive decline or a reduced risk of Alzheimer’s dementia include, but are not limited to, moderate to vigorous physical activity, an active social life, cognitively stimulating activity like visiting museums, reading books, or starting a new hobby, good quality and quantity of sleep, and stress reduction. Appropriate control of blood sugars and blood pressure are also important for brain health along with going to your primary care physician once a year for a medical evaluation.

How does this information add to our knowledge of diet and its possible impact on Alzheimer and dementia?

The current findings help us understand that the subclasses of flavonoids found in fruits and vegetables—with my research being focused on flavonols—can be independently beneficial for brain health. Even further, the constituents themselves are found to have an association that informs us as to the foods we can consume in our diet to ingest these flavonols.

When we think of foods, we naturally think about the nutrients, vitamins and minerals, contained in those foods. This research lends a further understanding of the contents of the foods we eat. Although very important, it is not just the nutrients in the foods we eat. It is also the bioactives contained in them.
It adds further confidence to the fact that the foods we are consuming do matter. Eat your fruits and vegetables, particularly dark leafy greens, and drink some tea every now and again. A healthy diet that contains various fruits and vegetables is critical for continued health, especially brain health and is a strong component of a healthy lifestyle.

What remains to be done in this area, research-wise? What would the next step be?

Initially, we would like to confirm these findings through other prospective cohort studies, specifically a more diverse population wherein we can generalize our findings to the public at large. Certainly, a clinical trial in which we could establish effect would be quite valuable and informative.

We believe that the beneficial association we found is due to the antioxidant and anti-inflammatory properties of flavonols. However, it is imperative to elucidate through what specific biologic mechanisms flavonols are working in our bodies, to better inform our compatriots and the public of the reason behind the potential benefit of flavonols. Further, determining how flavonols are metabolized once taken in through the diet, traverse the bloodstream, and cross the blood-brain barrier to actually function in the brain is necessary to accurately assess the need of foods in our diet that contain these bioactives.

Transcript edited for clarity.
REFERENCE
Holland TM, Agarwal P, Wang Y, et al. Dietary flavonols and risk of Alzheimer dementia. Neurology. 2020;94:1-8. doi:10.1212/WNL.