Stick to the spinach?

Does iron fortification work ? And if so, how ? Scientists from the US government are working on a new study to investigate the absorption and utilisation - the bioavailability - of various iron sources used to fortify foods today.

Agricultural Research Service​ scientists at the Grand Forks Human Nutrition Research Center Grand Forks together with Washington, D.C.-based non-profit group SUSTAIN, will evaluate the bioavailability of 'elemental iron powders' that are commonly used in food products such as ready-to-eat cereals.

For several decades, these powders have been the product of choice for boosting the iron content in breakfast cereals. As food fortifiers, they are relatively inexpensive and do not compromise product flavour, colour or shelf life. But the powders are produced through several different methods. Each method yields a product with distinct physical properties that, in turn, affect each product's nutritional bioavailability.

As a gauge for comparing the most commonly used iron powders, the researchers are using a soluble form of iron known to be highly bioavailable.

Preliminary studies, led by nutritionist Janet Ross Hunt, head of the GFHNRC's Mineral Nutrient Utilisation group, revealed considerable differences between the iron powders, with some only 20-25 per cent as bioavailable as the highly absorbed iron that served as the standard.

Using results from the preliminary study, the scientists have selected which powders to study further in humans. The team's next study, involving female volunteers, will test two of the powders against a placebo and the iron used as standard. They hope that the research will provide new information on the efficacy of elemental iron powders for improving iron status in humans.