Iodine is an essential mineral required for thyroid hormone production. Deficiencies of iodine lead to the development of goitre, a condition whereby the thyroid gland enlarges due to the hormonal and metabolic changes brought about by a failure to provide iodine for thyroid hormone synthesis. Iodine is essential to foetal growth and deficiency of iodine during pregnancy has been shown to cause reductions in intelligence scores during early life. Intakes of 150 μg per day iodine are recommended for adults in the united kingdom, but this is increased to 250 μg per day for pregnant and breastfeeding women. However, evidence suggests that this daily intake is not achieved by large number of those living in the United Kingdom. While goitre is rare in the United Kingdom, suggesting that outright clinical deficiencies are not present in most individuals, the low intakes are concerning because they may produce suboptimal health, and in particular may be problematic during pregnancy.
Researchers have investigated the iodine status of pregnant women in the United Kingdom. For example, in one study1, researchers took urine samples from pregnant women at 12, 20 and 35 weeks gestation and measured the iodine status of the women. At all time points combined, the median iodine content of the urine in the woman was 56.8 μg per litre, with the median creatinine content of the urine measured at 116 μg gram. The ratio of iodine to creatinine suggested that the cohort was mildly to moderately deficient in iodine. Individual analysis of the 12, 20 and 35 week gestation periods showed that this deficiency was evident throughout pregnancy, with iodine deficiency worsening as gestation proceeded. Only 3 % of the subjects were taking some kind of iodine supplement, suggesting that the typical Western diet consumed by the majority was not suitable for supplying adequate amounts of iodine to the women. Interestingly there was a seasonal variation in the iodine to creatinine levels in the women.
RdB
