Chapter II: Hemoglobin fortification of food. Absorption of hemoglobin and non‐heme iron.

Abstract

AbstractA simplified dose response study showed no significant reduction of absorption when the dose was increased from 0.9 to 4.2 mg hemoglobin iron, where absorption was about 20 per cent, but a significant reduction to 11 per cent when dose was increased from 4.2 to 19 mg hemoglobin iron. Nor was any significant absorption inhibition found when 3.5 mg hemoglobin iron were given together with an oatmeal porridge test meal. In contrast, this meal reduced non‐heme, ferrous iron absorption from 16.7 to 5.5 per cent.When given on a fasting stomach, no significant difference was found between absorption of hemoglobin and non‐heme iron at 3.5 mg dose levels. Numerically, hemoglobin iron was slightly superior.Meat products, expected to facilitate absorption of non‐heme iron were also studied, either given alone or together with a test meal. Mean absorptions of 3.5‐10 mg hemoglobin iron in different meals varied between 14.7 and 18.9 per cent, as compared to mean absorptions of non‐heme iron between 5.5 and 7.9 per cent.In contrast, hemoglobin iron absorption was reduced to only 0.8 to 7.6 per cent when baked products, such as bread or liver‐paté were studied. Even so, however, mean hemoglobin iron absorptions were 2 to 3 times higher than those of non‐heme iron.The cause of the absorption inhibition in bread was studied. No correlation could be found to the content of bran. No significant inhibition was found when unbaked, sour leaven dough was eaten. However, when hemoglobin was heated to baking temperature for baking times, absorption was reduced as in bread. Hemoglobin breakdown during prolonged heating is thus suggested.No significant difference was found between hemoglobin capsules and hemoglobin tablets.The present results suggest that hemoglobin fortification can contribute substantial amounts of absorbed iron. A single meal containing about 5 mg hemoglobin iron seems to provide about 0.8 mg of absorbed iron. This alone corresponds to the total iron requirements of a woman with a loss of 30 ml blood per menstruation.