Researchers from the University of Adelaide have found that the iodized salt used in bread is not enough to supply both a pregnant woman and her unborn child with the proper iodine levels to stay healthy. Pregnant women's urine samples revealed a deficiency in iodine levels that needed to be compensated and balanced with supplements in addition to their daily bread intake.

Iodine deficiency is one of the most common preventable causes of brain damage worldwide, according to the World Health Organization (WHO).

"Iodine is an essential element which is important for human brain development and thyroid functions," said one of the study's lead authors, Vicki Clifton, associate professor from the University of Adelaide at Robinson Institute and the Lyell McEwin Hospital.

In the study, 200 South Australian women's iodine levels were tested throughout their pregnancy and then six months post-birth in order to track deficiency peaks and dips.

"Despite the inclusion of iodized salt in bread, women who were not taking an iodine supplement during pregnancy were still suffering from iodine deficiency," Clifton said. "Those women who were taking a supplement in addition to eating bread with iodized salt were receiving health levels of iodine, well within WHO guidelines."

Iodine is an essential component of thyroid hormones, which play a large role in fetal brain development. Most iodine in the average diet comes from salt. There are about 95 micrograms of iodine per one-fourth teaspoon of iodized salt.

Twenty-five percent of the daily supply of iodine came from wheat because it was used in the processing of flour — at least up until recently, when the U.S. began to process flour with a chemical cousin of iodine, bromide. Bromide helps make the flour rise higher, but blocks the functionality of iodine from supplying the body with the thyroid boosts it needs. Bromide was classified by the International Agency for Research on cancer as a Class 2B carcinogen, and was banned from the UK in 1990 and then Canada in 1994. Although this study was conducted in Australia, bromide was not banned from Australia or the United States, making the deficiency a shared threat. It is unclear whether or not there is a deficiency in the UK or Canada, as there have been no studies to date on their countries' iodine levels in pregnant women.

Iodine's importance should not be understated, as it is a basic requirement for the body to function with healthy cellular and metabolic functioning. Low iodine levels can contribute to underactive and overactive thyroids and because of bromide's iodine blocking capabilities, its deficiency is linked to many thyroid disorders. According to a Breast Cancer Choices study, bromide levels are 50 times higher in the thyroid tissue of people with thyroid cancer.

Bromate levels were so controversial and still are to this day. In 1999, the Center for Science in the Public Interest (CSPI) petitioned the Food and Drug Administration (FDA) to ban the use of potassium bromate, an enriched flour version of bromide. The CSPI showed evidence of bromide records causing cancer in lab animals, but the FDA has planned to ban the additive.

"There's a lot of work going on around the world to ensure that pregnant women are receiving enough iodine for the health development of their unborn babies," said one of the lead authors, Basil Hetzel, a professor emeritus at University of Adelaide who began researching iodine deficiency more than 50 years ago at the Queen Elizabeth Hospital.

Last month, researchers from Surrey and Bristol Universities found the iodine deficiency was common among two-thirds of the women. The 1,000 family-study was published in the Lancet, and found women who had just a mild iodine deficiency were more likely to give birth to babies with lower verbal IQ scores and overall lower reading abilities than women who received the daily recommended amount.

If you're unsure of how much iodine you're consuming and whether it's enough for a healthy diet, look for symptoms such as goiters (enlargement of the thyroid gland), fatigue, weakness, depression, and weight gain. The most iodine-concentrated food sources include yogurt, cow's milk, eggs, strawberries, mozzarella cheese, certain fish and shellfish, as well as greens grown in iodine-rich soil.

What is a healthy level of iodine? Daily recommended micrograms:

-Infants up to six months: 110 mcg

-Babies seven to 12 months: 130 mcg

-Children one to eight years: 90 mcg

-Adolescents nine to 13 years: 120 mcg

-Adults 14 years and older: 150 mcg

"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," Hetzel said.