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Organic and long-life milk 'risk to children's IQ', new study

milk - Credit CC0 public domain.jpg

University of Reading scientists found that milk certified as 'organic', as well as conventional long-life milk treated at ultra-high temperatures (UHT), was a third lower in iodine than conventionally-produced fresh milk.


29 April 2015 - MedicalXpress


While the headline of this press release may be over-dramatic (as headlines usually are) - raising awareness of the serious implications of iodine deficiency in pregnancy is very important, as research has shown that:

  • most pregnant women in the UK have insufficient dietary intakes of iodine (as do many in other developed countries) 
  • even mild-moderate iodine deficiency in pregnancy can impair children's brain development and cognitive abilities.  
This level of iodine deficiency was found in 2/3 of UK mothers-to-be in the 1990s - and led to significant reductions in their children's verbal intelligence and reading at 8-9 years of age. See:

The increasing popularity of 'plant-based' diets since then has only been increasing these risks - as milk and dairy products are the main dietary source of iodine, and regular consumption of fish and seafood (the richest natural source) is the only other realistic way to achieve recommended iodine intakes without dietary supplementation.

This new research showed that both organic and UHT milk provides significantly less iodine than ordinary cows' milk (around 2/3 as much), which could therefore raise consumers' risks for inadequate intake of this essential nutrient. 

As the lead researcher comments: "Iodine deficiency ought to be a health problem from the past. But unless this situation is carefully monitored, we risk sleepwalking into a new health crisis in the 21st century."

For more information on good dietary sources of iodine - and the best supplements to use, as well as ones to avoid, for anyone not consuming fish and seafood or milk and dairy products at recommended intake levels - see the BDA factsheet on iodine 

For details of this research, see: 

And for more information on the crucial importance of iodine for mental, as well as physical health and wellbeing, see the following lists of articles, which are regularly updated:

29 April 2015 - MedicalXpress 

Researchers from Reading's Food Production and Quality Division said the findings had potentially serious public health implications, as most iodine in our diet comes from milk products.

Iodine is particularly crucial for the brain development of babies, particularly in the early stages of pregnancy. Studies have found that iodine deficiency in mothers during these stages can lead to children with a lower IQ.

Professor Ian Givens, University of Reading, who led the research, said:

"People are increasingly buying organic and UHT milk for perceived health benefits or convenience. But our research shows that this trend could have serious implications for public health.

"Iodine deficiency ought to be a health problem from the past. But unless this situation is carefully monitored, we risk sleepwalking into a new health crisis in the 21st century.

"Organic and UHT milk is not bad for you, and drinking all types of milk has numerous health benefits. But to get the same amount of iodine as in a pint of conventional pasteurised milk, you would need to drink around an extra half-pint of organic or UHT milk."

A previous study has shown that some organic milk, produced in summer when organic dairy herds are fed almost exclusively on grass, was lower in iodine.

This latest study shows that the trend is year-round, as well as making an assessment of iodine content in UHT milk for the first time.