A mandatory program of iodine supplementation in bread introduced in 2009 to help provide a boost to iodine levels in the community does not provide sufficient healthy levels of iodine for pregnant women and their unborn children.
"Iodine is an essential element which is important for human brain development and thyroid function," says Associate Professor Vicki Clifton from the University of Adelaide’s Robinson Institute and the Lyell McEwin Hospital.
A/Professor Clifton and her colleagues, including Emeritus Professor Basil Hetzel AC, advise pregnant women to keep taking iodine supplements, after study to determine whether or not the supplementation program was having a positive impact on iodine levels for pregnant women.
"We found that the women in the study were mildly iodine deficient. Despite the inclusion of iodised salt in bread, women who were not taking an iodine supplement during pregnancy were still suffering from iodine deficiency," A/Professor Clifton says.
"Those women who were taking a supplement in addition to eating bread with iodised salt were receiving healthy levels of iodine, well within World Health Organisation (WHO) guidelines."
This is the latest study to follow on from the pioneering work of Emeritus Professor Hetzel, who began researching iodine deficiency more than 50 years ago at the Queen Elizabeth Hospital, in collaboration with the Papua New Guinea Public Health Department. It revealed very low urine iodine levels and high rates of goitre were associated with a form of brain damage called 'cretinism'. Professor Hetzel showed that this brain damage could be prevented by correcting the severe iodine deficiency before pregnancy.
"There's a lot of work going on around the world to ensure that pregnant women are receiving enough iodine for the healthy development of their unborn babies," says Professor Hetzel, who is also a lead author on this current study.
"The message is simple: by taking iodine supplements, pregnant women will be able to prevent brain and organ development problems in their babies, and also maintain a healthy level of iodine for themselves."
Professor Hetzel says Australia continues to be a leader in this field, "but there is still very little public understanding about the dangers of iodine deficiency".
"Iodine deficiency is now recognised by the WHO as the most common preventable cause of brain damage in the world today," he says.
The women in the study were tested throughout their pregnancy and six months after giving birth.