Polyphenols are a large class of phytonutrients found in most plants. There are over 4,000 polyphenol compounds, many are powerful antioxidants that can neutralise free radicals, reduce inflammation and slow the growth of tumours.
They are characterised by the presence of more than one phenol unit (or building block per molecule). They can be found in fruit and vegetables, nuts, legumes, green tea, black tea, red wine, coffee, chocolate and olives, and some polyphenols are specific to particular food.
Polyphenols add bitterness or bite to foods. For instance, tea that’s brewed too strong, the taste of raw cocoa or the back palate of red wine, anything that makes your mouth pucker generally contains polyphenols.
In plants, they help defend against attack by insects, prevent microbial infections, deter herbivores (sensory properties i.e. colour, taste and smell) and provide screens to protect against UV radiation.
Good sources of polyphenols early all fruits and vegetables, especially berries, grapes, and greens, along with olives, cocoa, red wine and green and black tea.