There is evidence of transfer of isoflavonoids to the foetal compartment at levels similar to those in maternal plasma and the occurrence of post-natal exposure through transfer in breast milk

2. Generally speaking, isoflavonoids and lignans are ingested largely as glycosides, which undergo hydrolysis, possibly in the stomach, under the action of acid, or in the lower gut, under the action of the gut microflora. The deglycosylated (aglycone) compounds may be further metabolised by the gut bacteria and/or absorbed. Once absorbed, these compounds are rapidly and extensively re-conjugated, largely with UDP-glucuronic acid, and excreted in the bile or urine. Biliary conjugates are hydrolysed by the gut bacteria and/or excreted in the faeces or further metabolised and/or reabsorbed (enterohepatic circulation) or degraded.