More recent reviews suggest that plant extracts high in proanthocyanidins could have differential inhibitory effects on carbohydrate digestion enzymes depending on their respective phenolic compositions, complexity, and polymerisation [19,44], such that proanthocyanidin oligomers may be preferred over longer-chain polymers as better alpha-glucosidase inhibitors for diabetes prevention and management [45]. This evidence concerns the gene GAA and diabetes mellitus.