Ellagitannins - nature, occurrence and dietary burden

The occurrence of ellagitannins in common foodstuffs is limited to a few fr uit and nut species. Dietary intake of ellagitannins is largely explained b y the consumption of strawberries, raspberries and blackberries. No reliabl e figures are available for the ellagitannin burden, but it will probably n ot exceed 5 mg day(-1). Their bioavailability is not well defined. A fracti on of the ellagitannins ingested is hydrolysed in the gut and the resulting ellagic acid absorbed and metabolised, but whether intact ellagitannins ar e absorbed is not clear. There are apparently conflicting claims for benefi cial and toxic effects caused by ellagitannins, ellagic acid or ellagitanni n-containing extracts in various animal species including rodents and rumin ants. It seems unlikely that normal consumption can cause toxic effects in man, but any attempt to increase the intake significantly in pursuit of the suggested benefits should be resisted until the metabolism and pharmacokin etics are better understood. (C) 2000 Society of Chemical Industry.