Polyphenols are a large family of naturally occurring phenols that are abundant in plants and structurally diverse. They are micronutrients that naturally occur in plants and are included in many supplements, though they are also easy to get in your diet from foods like fruits, vegetables, teas, and spices. Polyphenols include flavonoids, tannic acid, and ellagitannin, some of which have been used historically as dyes and for tanning garments. There are more than 8,000 different types of polyphenols that have been identified so far. Some polyphenols that have gained popularity are epigallocatechin gallate (EGCG) in green tea and resveratrol in grapes and wine.
Polyphenols are not well-defined, but it is generally agreed that they are natural products "having a polyphenol structure (i.e., several hydroxyl groups on aromatic rings)" including four principal classes: "phenolic acids, flavonoids, stilbenes, and lignans". Polyphenols are often larger molecules (macromolecules) and their upper molecular weight limit is about 800 daltons, which allows for the possibility to rapidly diffuse across cell membranes so that they can reach intracellular sites of action or remain as pigments once the cell senesces.
Polyphenols are beneficial plant compounds with antioxidant properties that may help keep you healthy and protect against various diseases. They can act as antioxidants, meaning they can neutralize harmful free radicals that would otherwise damage your cells and increase your risk of conditions like cancer, diabetes, and heart disease. Polyphenols are also thought to reduce inflammation, which is thought to be the root cause of many chronic illnesses. Studies show that people who have polyphenol-rich diets — consuming more than 650 milligrams per day — have lower death risks than those who get less than 500 milligrams per day.
Many fruits and vegetables are high in polyphenols, but they are also found in beans, cereals, and soy. Some examples of polyphenol-rich fruits and vegetables include blueberries, cherries, strawberries, blackberries, and spinach. Polyphenols are not listed on nutrition fact labels.
