Dairy Council

Iodine deficiency in pregnancy has been linked to lower IQ and reading ability in children according to Professor Margaret Rayman, a specialist in nutritional medicine from the University of Surrey. Professor Rayman spoke at the 27th Annual Dairy Council Nutrition Lecture at Ulster University on Wednesday 2nd November.

As pregnancy is the most important time for brain development, Professor Rayman and her research team have evaluated iodine status in UK pregnant women, finding that levels of iodine are lower than the World Health Organization (WHO) cut off for adequacy in pregnancy. 

The research found a significant association between low iodine status in mothers in early pregnancy and their children’s brain development. Children whose mothers were iodine deficient in pregnancy (67% of those surveyed) had an approximately 60% greater risk of being in the bottom quarter of scores for IQ and reading ability at 8 to 9 years old. The more severe the level of iodine deficiency in the mother, the worse the effects on verbal IQ and reading comprehension.

Speaking at the Lecture, Professor Rayman stressed that to avoid compromising their children’s brain development, women of childbearing age who might become pregnant need to ensure they have an adequate iodine intake from dietary sources. In Northern Ireland we get most of our iodine intake from milk and dairy products and the increase in sales of milk–alternative drinks over recent years, which contain little or no iodine, unless fortified with iodine (which very few are) is, according to Rayman, a worrying trend.

“The rise in consumption of milk–alternatives such as soya and almond drinks, the majority of which do not contain iodine, means that some women may be missing out on this vital nutrient,” said Professor Rayman. “Individuals who consume these drinks in preference to cows’ milk may be at risk of iodine deficiency and may be unaware of the potential consequences for their babies’ cognitive and motor development. It is important that women ensure that they have an adequate iodine intake from dietary sources which in the UK are mainly cow’s milk and dairy products, with contributions from fish and eggs to avoid compromising their children’s brain development.”  

Other studies have demonstrated that low intakes of iodine are not just an issue for pregnant women but iodine is also lacking in the diets of teenage girls. The most recent National Diet & Nutrition Survey found that over a quarter of girls aged 11–18 in the UK were not getting sufficient iodine.

Dr Mike Johnston MBE, Chief Executive of the Dairy Council for Northern Ireland commented, “Since the first Lecture in 1991, the purpose of the co–operation between Ulster University and the Dairy Council has been to provide a forum in which world class research and leading edge thinking can be presented in key areas of human nutrition. Professor Rayman has continued this purpose by highlighting the importance of iodine, and milk, as a dietary source.”

References:
1. Bath SC, Rayman MP, Steer CD, Golding J, Emmett P. (2013) ‘Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC)’. The Lancet, Lancet; 382(9889): 331–7.
2. National Diet and Nutrition Survey Results from Years 5 and 6 (combined) of the Rolling Programme (2012/2013 – 2013/2014).

Download the Lecture summary here.