Polyphenol interaction with food carbohydrates and consequences on availability of dietary glucose

• Polyphenols known to indirectly impact glucose uptake and metabolism.
• Monomeric polyphenols interact weakly with carbohydrates.
• Recent evidence indicates the polymeric tannins strongly complex amylose.
• The tannin–amylose complexes are non-digestible.
• Opportunities to utilize tannins to reduce dietary glucose release from starch.

Polyphenols are known to indirectly influence glucose metabolism, for example, via inhibition of digestive enzymes. Less clear is whether polyphenols can complex with, and directly reduce carbohydrate digestion. This is relevant because it can provide a practical mechanism to reduce caloric load of foods. Direct interaction of carbohydrates with monomeric polyphenols appears to have little practical consequence on glucose availability. Recent evidence supports strong and specific polymeric polyphenols (tannins, especially with MW > 1000) interaction with carbohydrate polymers via hydrogen bonding and hydrophobic interactions. For example, amylose component of starch forms non-digestible complexes with tannins. This is interesting because starch is the primary dietary source of glucose. Thus research efforts in this area should focus on optimizing and uncovering consequences of starch–tannin interactions.