Iodine is a major component for thyroid hormone secretion, which helps in controlling the heart rate and metabolic rate. During pregnancy, iodine helps in fetal growth and brain development. Low iodine levels in pregnant women may lead to lower IQ levels or mental disabilities. Iodine deficiency was especially observed among women of childbearing age in industrialized countries.

A research group from Northern Ireland, have found that increased consumption of cow’s milk and dairy products would directly increase iodine levels, especially in pregnant women. In numerous countries, cows milk is considered the most prominent source of iodine.

In the study, 78 iodine deficient women between 18-45  years of age, were divided into either a controlled group or an intervention group. The women in the intervention group were made to consume three liters of semi-skimmed cows milk for 12 weeks. They consumed the milk in the form of direct milk, milkshakes, tea and coffee along with their normal diet. Blood and urine samples were taken during the 6^th week and 12^th week to measure their iodine levels. The results showed a significant increase in iodine levels of the women in the intervention group but there was no significant increase in thyroid hormone levels even after 12 weeks.
As a result, it was suggested to encourage the cows' milk consumption to prevent iodine deficiency among the public.