Unilever explores vegetarian iron for fortification

Sodium iron chlorophyllin obtained from mulberries was found to be as bioavailable as heme iron, scientists from Unilever R&D Vlaardingen in the Netherlands report in the Journal of Agricultural and Food Chemistry​.

Understanding the challenge​

Iron deficiency remains the leading nutrient deficiency in both developed as well as developing countries. It affects around one in five women in the UK.

Fortifying foods with iron also poses several challenges for the food industry, most notably with regards to effects on colour, taste, and the shelf-life of the food.

“Iron fortification of foods generally has used non-heme iron sources, as these are cheap and easily available,”​ explained the researchers, led by Silvia Miret. “Nevertheless, these iron sources have poor bioavailability and often affect the organoleptic characteristics of the product. ​

“The use of heme-iron as a fortificant has been limited,” ​they continued. “This probably responds to a myriad of factors including the elevated costs of haemoglobin or haemoglobin extracts, the intense colour of haemoglobin, the large amounts of haemoglobin required, and its animal origin, which means that it might not be consumed in certain regions of the world.”​

In order to address this issue, the researchers looked at iron compounds from vegetable origins which are analogues of heme-iron. They focussed their attention on sodium iron chlorophyllin, a compound described by the researchers as a “water-soluble semi-synthetic chlorophyll derivative where the magnesium in the porphyrin ring has been substituted by iron”​.

By using Caco-2 cells to model bioavailability in the human intestine, the researchers found that sodium iron chlorophyllin was “stable under simulated gastrointestinal conditions and is able to deliver bioavailable iron”.​

Various food matrices were considered, including water, dough, powder drink, and chocolate. Iron sulphate was used as a comparison. Miret and her co-workers report that, as with heme-iron, the bioavailability of the iron from sodium iron chlorophyllin was dependent on the food matrix. Indeed, calcium was found to inhibit the bioavailability.

Choose your matrix carefully​

“It should be noted that sodium iron chlorophyllin is intensely green, and therefore, it dramatically affects the colour of the food matrixes where it is added,”​ wrote the researchers. “Coloration could be masked in the presence of cocoa both in chocolate bar formats as well as in drink products.”​

Miret and her co-workers note that the fruit drinks containing strawberry have been found to effectively mask the colour of the compound, suggesting an alternative delivery method for the compound.

“Nevertheless, it is clear that for this compound colour is a major factor and that strategies should be considered for masking or linking it to particular green flavours such as pistachio or kiwi,”​ they added.

Promising beginnings…​

“Potentially, sodium iron chlorophyllin could be used as an iron fortificant from vegetable origin with high bioavailability similar to that of heme,”​ wrote the researchers.

“Adequate product formulation and in particular the absence of calcium would be essential to ensure iron delivery. These iron bioavailability results should be corroborated in human intervention studies,”​ they concluded.

Source: Journal of Agricultural and Food Chemistry​
Published online ahead of print, doi: 10.1021/jf903177q
“In Vitro Bioavailability of Iron from the Heme Analogue Sodium Iron Chlorophyllin”​
Authors: S. Miret, S. Tascioglu, M. van der Burg, L. Frenken, W. Klaffke