Due to low absorption polyphenols are held to be poor in vivo antioxidants. The idea that is being put forward is that what happens in the gut can have systematic affects. The antioxidant and iron chelating properties of polyphenol compounds in the gut can have large effects on aconitase 1 in the gut and other enzymes in the TCA cycle in the gut with systematic effects then occurring. Polyphenols are not well absorbed, however, polyphenols do not have to be well absorbed to have large systematic effects. Polyphenols are everywhere in plant based foods. Difficulties only arise with polyphenol extracts such as natural flavors and foods processed to have concentrated polyphenols such as spices, sodas, coffee and tea.