Effects of combined riboflavin and iron deficiency on the hematological status and tissue iron concentrations of the rat.

Interactions of riboflavin and iron deficiencies on utilization and storage of iron in the rat were investigated. Rats were fed diets deficient in iron (ID), riboflavin (RD) or iron and riboflavin (DD) for a period of 7 wk, at which time they were either killed and measurements of hematological indices and tissue iron concentration done or a further group of DD rats was supplemented with either iron, riboflavin or both nutrients for 2 wk. Growth was impaired in all deficient groups but the impairment was greatest in the DD rats. Iron depletion was associated with the greatest reductions in hematological indices and tissue iron concentrations, riboflavin depletion the least, while the combined deficiencies had intermediate effects. Riboflavin deficiency was found to have a "sparing effect" on iron status probably because the lower growth rate associated with riboflavin deficiency reduced iron requirements. Refeeding either iron alone or iron with riboflavin to the DD rats resulted in significant improvement in hematological status, but there was no significant difference in the response to either supplement. Feeding riboflavin alone to DD rats resulted in a further depression of hematological status and tissue iron concentration.