American Journal of Clinical Nutrition, Vol 25, 401-411, Copyright © 1972 by The American Society for Clinical Nutrition, Inc.

Model for measuring dietary absorption of heme iron: test with a complete meal

¹ From the Instituto Venezolano de Investigaciones Científicas, Apartado 1827, Caracas, Venezuela

A simple and inexpensive method for measuring the absorption of heme iron from a diet is proposed. It is based on the fact that a small amount of hemoglobin iron (0.1 mg) is absorbed at the same level that 2 mg of meat iron is when they are mixed before ingestion. The ratio of absorption of these foods remained constant, close to unity, along a wide absorption range, and was not affected when these foods were mixed with vegetables or were part of a complete diet.

A small amount of inorganic iron (0.1 mg) such as ferric salt can apparently be used for measuring the total absorption of vegetable foods. The absorption of this extrinsic tag would serve as a biopsy for the non-heme iron pool.

The absorption of heme and non-heme iron was measured in a complete meal consisting of three vegetable foods and meat. The amount of meat which represented one-third of the total cooked meal was responsible directly or indirectly for 80% of the nutritive iron value. It may be estimated that the nutritive iron value from the same meal, but without meat, will be reduced considerably.

The data presented suggest that this inexpensive method for measuring heme and non-heme iron from a diet has enough experimental support to predict its successful use in other diets with different proportions of animal and vegetable foods.