Thursday, 9 May 2013

Iodine nutrition in pregnancy

Iodine Nutrition in Pregnancy

Australian studies show brain impairment due to iodine deficiency in the womb is not reversible

Hannah Devlin,  Science Editor, wrote in the Times on 1 May 2013  that scientists in Tasmania  have found babies whose mothers have low levels of iodine during pregnancy have worse literacy skills in childhood. At nine years old, children who did not receive enough iodine in the womb performed worse than their peers in reading and spelling tests. Very importantly the scientists also reported:-

“Although the participants’ diet was fortified with iodine during childhood, later supplementation was not enough to reverse the impact of the deficiency during the mother’s pregnancy.”

Maybe it will now be better appreciated by the Department of Health in the UK that mild iodine deficiency of the mother (i.e. a deficiency that is not severe enough to result in cretinism in the baby, as in the Tasmania study) can have significant and lifetime effects.

Can we expect advice in the UK about iodine for women of reproductive age being brought into line with WHO recommendations in the near future?  I suspect not.

Department of Health advice and SACN position paper on Iodine

However there are signs at last that the Department of Health and the Scientific Advisory Committee on Nutrition (SACN) that advises it are coming to terms with the problem of iodine deficiency in young women and with the implications for foetal brain development.

The NHS website  from November 2012 contains the following advice about iodine (search for iodine) :-
Adults need 0.14mg of iodine a day. Most people should be able to get all the iodine they need by eating a varied and balanced diet.
However, if you are pregnant, you may need to take iodine supplements. This is because an iodine deficiency during pregnancy can harm the development of your baby.
If you take iodine supplements, do not take too much because this could be harmful.
Taking 0.5mg or less a day of iodine supplements is unlikely to cause any harm.

The SACN is in the late stages of producing a position paper on iodine nutrition. Gestation of the paper has been prolonged. It has been discussed in February and June 2012 and February 2013 and will again be considered in June 2013. It is presumed that it will then be finalised and presented to the Department of Health and will be posted on (where the draft paper and discussions can be read).

SACN seem to have accepted, somewhat reluctantly, that urinary iodine levels are worthy of investigation in the UK and it is likely that their use will be included somehow with the Nutritional Diet and Nutrition Survey; it is the NDNS which is based on food analysis combined with information on “typical” diets that has been traditionally used to estimate, by calculation, the adequacy of diets of different sectors of the population.

The SACN would seem to have fully appreciated the importance of iodine for the foetus. It is hoped that it will not take many years before women of reproductive age are advised to ensure they have adequate iodine intakes ideally in their diet but if necessary by iodine supplements. It is not possible to envisage that widespread iodisation of salt or of bread would ever be possible in the UK. Too many people would object that their rights/freedom would be being impinged by supplementing a foodstuff.

Unfortunately it seems that the inevitable requests for further funds for research may impede unequivocal advice being given for iodine supplementation before and during pregnancy. On the one hand the research workers do not want to give the impression that they know enough of the answers and thereby need no more funds and on the other the bureaucrats are likely to be happy not to have to make a decision.

Although the scientists working on iodine deficiency disorders across the world have known for many years that foetal brain damage caused by the deficiency is irreversible it would seem that scientists in the UK are not prepared to use the word irreversible because it is likely to frighten people. Perhaps we, the research workers and the   Department of Health need scaring into action.  

Meanwhile please pass this on to all friends and relatives for whom it might it be relevant.

Vic Shorrocks                                                                                                 9th May 2013

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