Mothers-to-be have many things to worry about when they’re expecting, and consuming a healthy diet is usually a top priority. While most pregnant women know to dutifully start munching on more fruits, vegetables and sources of calcium, the importance of less promoted trace minerals like iodine is something they rarely think about. Doctors know that severe iodine deficiency during pregnancy can cause mental disabilities in children — but the newest research is showing that even milder iodine deficiencies during pregnancy can have moderate – yet alarmingly permanent – effects on children’s mental development.
Your body needs iodine for proper thyroid function, but your body doesn’t naturally produce it; therefore, you must obtain this important mineral from your diet. Studies have shown that iodine is especially important for pregnant women to consume. Current recommendations by the Dietitians of Canada state that adults should consume a minimum of 150 mcg of iodine per day, that pregnant women should consume a minimum of 220 mcg per day, and that breast-feeding women should consume a minimum of 290 mcg per day.
Iodine is present in most dairy foods (such as milk, cheese, yogurt, etc.), certain fruit and vegetables (such as sea vegetables, broccoli, cauliflower, strawberries, etc.) and also in certain types of fish (cod, haddock and tuna). However, the primary source of iodine for most of us is ionized table salt. A healthy route to obtaining sufficient iodine is through food sources and modest salt intake.
Kristen Hynes, from the University of Tasmania, conducted a study that evaluated 228 pregnant patients from The Royal Hobart Hospital between 1999 and 2001. The women were divided into two groups – patients with urinary iodine levels below 150 mcg (mildly deficient) and patients with urinary iodine levels above 150 mcg (normal). Educational assessment data from the Australian national curriculum and Tasmanian state curriculum evaluated the children born to these women, 9 years after birth.
The children that were born from mildly iodine-deficient mothers scored, on average, 371 points on the national spelling test and 377 points on the grammar test. Conversely, the children of women who had sufficient iodine levels scored significantly higher – specifically, 412 points on the spelling test and 408 points on the grammar test, on average. In addition, children that were born to women who were mildly iodine deficient scored approximately 6 percent lower on English literacy tests compared to children that were born to women who had sufficient iodine levels.
The research indicates a definitive relationship between mild iodine deficiency during pregnancy and poorer test scores in children born to these women. These results fall in line with other studies that have shown that iodine deficiency interferes with auditory pathways in young brains. This interference affects the child’s ability to process verbal information, as well as other forms of auditory stimulation.
While this research may leave expectant mothers questioning whether they should take an iodine supplement during pregnancy, it’s important to remember that too much of this mineral is also not a healthy choice. The safe maximum limit for healthy adults and for pregnant women is 1,100mcg.
Excessive consumption of iodine can lead to thyroid dysfunction and/or goiter. In addition to an overall healthy diet, adding in a few extra portions of dairy each day and a couple of portions of fish each week will help to ensure healthy and sufficient levels of iodine intake.