The Underappreciated Polyphenols Needed in Every Diet
Updated: Jan 19
You know about fiber (ok, there is probably so much more you could know about fiber, but that is another topic). You hear about vitamins A, C, E, and maybe you are taking those.... thinking they are covering you and filling a gap you know is there in your diet. As we hear about inflammation's role is disease more and more these days, and you get your gardening on this spring, let's get into some fundamentals of the science of a plant heavy diet.
Polyphenols are produced by plants to help protect them from ultraviolet radiation and other environmental threats like pathogens. Polyphenols give the bitterness, acidity, color, flavor, and scent to plants. Think of the strong herbal astringency of rosemary, basil, or sage. Herbs are among the highest in polyphenol content, though we consume them in such small quantities they may not contribute as other plants in our diet. But all the more reason to plant some basil for pesto, drop a sprig of rosemary in your soup pot, or hey - have you ever made a compound butter with sage? If not, consider the seed planted and you're welcome.
Polyphenols give plants, and us, oxidative stability. Oxidative stress is in part unavoidable, though can be mitigated by not over-eating, avoiding pollution as much as possible, not smoking, and eating a more anti-inflammatory diet (enter polyphenols). Potent antioxidants act through redox balance, donating electrons to free radicals. These molecules also have anti-inflammatory properties, mitigating cytokine pathways, and research shows evidence of their role in the prevention and treatment of diseases connected to oxidative stress and inflammation, such as cancer, cardiovascular, and neurodegenerative disorders. Polyphenols are involved in the modulation of some cell-signaling pathways and mediators of inflammation. By consuming a polyphenol-rich diet, we can neutralize the inflammatory effects of eating itself, as there is oxidative stress associated with the consumption of food as it is metabolized and stimulates the electron transport chain to produce energy. Long term, research suggests polyphenols protect against cancers, cardiovascular disease, type 2 diabetes, osteoporosis, pancreatitis, gastrointestinal problems, lung damage, and neurodegenerative diseases. Using polyphenols as supplements should be done with caution, as over-consumption raises safety concerns.
Keep in mind supplements are not regulated, so working with a healthcare practitioner once you move into supplement territory is recommended. For polyphenols to have an impact, we do want a variety (eat the rainbow) and consider bio availability (some raw, some cooked, but not cooked excessively).
Good news, cocoa powder and chocolate are rich in the polyphenols catechins and proanthocyanidins. Berries have anthocyanins (a polyphenol, there are many with different names), and generally the darker in color, the higher the polyphenol content. Fruits generally have more compared to vegetables, with globe artichoke heads, onion (red or yellow), shallot, and spinach being on the higher end, while broccoli, asparagus, potato, endive, lettuce, and carrot have less. Nuts and seeds are also rich lobe artichoke heads and red and green chicory (chlorogenic acid), onion (red or yellow), shallot and spinach (rich in flavonols). Coffee (contains chlorogenic acids) is the highest polyphenol beverage, with black and green tea (catechins, theaflavins and proanthocyanidins), and red wine (containing catechins, proanthocyanidins, anthocyanins and hydroxycinnamic acids) being other sources in the beverage world. Fruit juices are lower in polyphenols, and juice is generally not recommended anyway due to its liquid sugar issues.
Cory H, Passarelli S, Szeto J, Tamez M, Mattei J. The Role of Polyphenols in Human Health and Food Systems: A Mini-Review. Front Nutr. 2018;5:87. Published 2018 Sep 21. doi:10.3389/fnut.2018.00087
Pérez-Jiménez, J., Neveu, V., Vos, F. et al. Identification of the 100 richest dietary sources of polyphenols: an application of the Phenol-Explorer database. Eur J Clin Nutr64, S112–S120 (2010). https://doi.org/10.1038/ejcn.2010.221
Silva RFM, Pogačnik L. Polyphenols from Food and Natural Products: Neuroprotection and Safety. Antioxidants. 2020; 9(1):61. https://doi.org/10.3390/antiox9010061