In last month’s E-News we wrote about the new mandatory addition of folic acid to wheat flour for bread-making, introduced to help reduce the incidence of neural tube defects in babies. This month we can report that bread has also become a source of iodine – 3-4 slices (100g) of bread now provides around 46ug of iodine. A seemingly micro amount, this is actually almost one third of the daily requirement of iodine for Australian adults and over one third of the recommended amount for children. This is a step in the right direction to help combat the world’s most preventable cause of mental retardation – iodine deficiency.
Mandatory fortification of all commercial breads (except organic bread) with iodised salt came into force on 9th October 2009. No additional salt is being added to bread, bakers will simply use iodised salt instead of standard salt hoping to reduce a re-emergence of iodine deficiency amongst many Australians. We only need about 1 teaspoon in a lifetime, however iodine is an essential trace mineral needed for regulation of normal growth and metabolism and is crucial at certain stages of foetal development during pregnancy and early childhood. The body can only store a small amount and regular top ups are needed from a variety of foods in a healthy balanced diet. Iodine is naturally found in foods such as oysters, fish, tuna, sushi (seaweed), dairy products and eggs.
A recent study published by Gordon et al in the American Journal of Clinical Nutrition, found that iodine supplementation can improve cognition in even mildly deficient children. This is good news considering the National Iodine Nutrition Study conducted in 2003-04 found that mainland Australian children on average are borderline iodine deficient, with NSW and Victorian children being mildly iodine deficient. Although the amount supplemented in this study was three times greater than the amount now found in 100g of bread (fortified with iodised salt), Food Standard Australia New Zealand (FSANZ) expects mandatory iodine fortification to reduce inadequate iodine intakes from 43% to less than 5% in the Australian population.
Creswell et al. Are Australian children iodine deficient? Results of the Australian National Iodine Nutrition Study. MJA 2006;184:165-169.
Gordon et al. Iodine supplementation improves cognition in mildly iodine-deficient children. AJCN 2009;90(5):1264-1271.