Increasing children's iron intake

We thank John O'Brien for his interest in the article on iron deficiency anemia in young people¹ and for his appropriate questions concerning the bioavailability and hence absorption of iron from commercially fortified cereals. This issue has recently been thoroughly reviewed.²

Iron bioavailability depends on the iron compound used, the level of fortification of the food consumed, the iron status of the consumer, and the presence of inhibitors and enhancers of iron absorption in both the cereal and the overall diet. Elemental iron powders have been used for the commercial fortification of cereals for more than 50 years and continue to be the most widely used form of iron for this purpose. The 3 main classes of elemental iron powders are iron reduced by hydrogen or carbon monoxide, electrolytic iron and carbonyl iron. These compounds have the advantage of causing few if any changes in the colour or flavour of prepared cereals. However, the absorption of elemental iron powders is lower than that of other fortificants such as ferrous sulfate and is often less predictable because of variations in particle size, particle distribution, shape and density. Of the 3 main types of elemental iron powders commercially available, hydrogen-reduced iron is the most commonly used in ready-to-eat breakfast cereals.

A recently completed double-blind randomized trial³ involving 20 nonanemic female volunteers examined absorption of iron from Corn Flakes (Kellogg's; fortified with hydrogen-reduced iron) given as part of a typical Western breakfast. Geometric mean iron absorption from the fortified cereal was 14.1%. If we use this absorption value and consider, for example, Cheerios (General Mills; 8.1 mg iron per 30-g serving) or Count Chocula (General Mills; 4.5 mg iron per serving), a single serving of Cheerios will provide 1.1 mg and of Count Chocula 0.63 mg of “absorbed” iron. These quantities meet or exceed the recommended amount of absorbed iron for children up to 8 years of age.⁴ Thus, when used on a regular basis, ready-to-eat breakfast cereals are a reasonably good source of bioavailable iron.

Stanley Zlotkin Professor Departments of Paediatrics and Nutritional Sciences University of Toronto Toronto, Ont. Claudia Schauer Clinical Research Project Manager Program in Metabolism Research Institute The Hospital for Sick Children Toronto, Ont.