Although the biology of neurodegenerative disorders is complex, most forms are associated with the development of abnormal protein bundles called “inclusion bodies” within brain cells. You’re probably already familiar with some of these bundles when people discuss plaques and neurofibrillary tangles in relation to Alzheimer’s disease (AD).
Plaques and tangles are made up of misfolded proteins, which unfortunately have a tendency to attract other proteins to themselves, producing larger and larger bundles. As you might imagine, having bundles of misfolded proteins inside a cell can really gum up the works, wreaking havoc on the cell’s machinery. There’s also evidence that these misfolded proteins act like prions (e.g., Mad Cow Disease), which are misfolded proteins that attract and reshape other proteins, and can be passed from cell to cell, making them contagious [1, 2]. Usually, however, transmission between organisms requires consumption of the infected tissue of one animal by another, so it’s a good thing we’re not in the regular habit of cannibalism! 
One of the greatest pharmacological challenges for researchers in developing treatments for neurodegenerative disorders is finding a medication that targets these protein bundles directly. Thankfully, there’s a growing body of research indicating that many plant-derived polyphenols may not only prevent the build-up of neurodegenerative protein bundles but also bind to and neutralize those already present. Many of these plant-derived chemicals are also able to cross through the blood-brain barrier and enter the brain.
What are polyphenols? Polyphenols are chemicals that plants produce that help protect against things like insects, fungi, and UV radiation. But polyphenols also give fruits their appetizing colors, making them attractive to larger animals like us who, theoretically, then go on propagate their seeds. The better known families of polyphenols are the flavonoids and tannins and can be found in foods like tea, grapes, blueberries, cherries, and even soybeans.
Question: Are you a tea fanatic like me? Well, if you want your full dose of tea-derived polyphenols, be sure not to add milk or any other protein to your drink (including creamer, almond milk, or other substitutes). One of the ways that polyphenols neutralize danger in the plant– and probably also the ways in which they neutralize protein bundles in neurodegenerative disorders– is that they LOVE to bind to proteins. So, once you put that milk in your tea, all those lovely healthy polyphenols bind to the proteins in the milk and can no longer be absorbed by your body during digestion. Such a shame!
There’s currently no indication that polyphenols consumed in the foods we eat are in any way harmful and instead act as remarkable antioxidants and anti-inflammatory agents, helping to bolster human health. However, some polyphenols are also available as high-concentration supplements, such as green tea and grape seed extract. The major risk for these types of supplements that I’m aware of is the potential for liver toxicity when either the dosage is too high or an individual has a genotype that may predispose them towards a slower metabolism of the supplement. Therefore, caution is warranted when adding supplements to your medication regime. Before starting, it’s best to consult your physician to ensure the supplements will be metabolized well and won’t interact with any other medications you’re taking. (As an example, many polyphenols interact with or affect the use of blood thinners.)
Nevertheless, I’m really hopeful these phytochemicals will be useful in the treatment and prevention of neurodegenerative disorders in future, as well as the enhancement of cognitive longevity. I for one plan on continuing to take my daily green tea extract to keep the little gray cells working!