Observations on iron in the jejunal lumen after a standard meal.

For two hours after the ingestion of a standard meal with an iron content of 3.45 mg there is a rise in iron concentration in the jejunal lumen. Initially this is in a high molecular weight form but there is a steady increase in the concentration of low molecular weight compounds. This is consistent with the gradual intraluminal transfer of iron from a mucopolysaccharide carrier to low molecular weight ligands before absorption.