Kinetics of iron absorption from ferrous fumarate with and without galacto-oligosaccharides determined from stable-isotope appearance curves in women.

GOS increases iron solubility from FeFum at physiological pH characteristic of the proximal duodenum. The absorption kinetics in vivo are consistent with effects on iron absorption in the proximal, rather than distal parts of the gut. There was no overall effect of GOS on FIA in-vivo, but the interaction of GOS and SF on FIA might benefit iron-deficient women, potentially mediated by the higher solubility shown in-vitro.The study was registered at clinicaltrials.gov as NCT03996421 (https://www.clinicaltrials.gov/ct2/show/NCT03996421).