Iodisation of salt

Iodine deficiency has substantial effects on growth and development and is the most common cause of preventable mental impairment worldwide. Mild deficiency impairs cognition in children, and moderate to severe iodine deficiency in a population reduces IQ by 10 – 15 points. Globally it is thought that 20 million children are born every year at risk of brain damage due to iodine deficiency. Iodine supplementation before pregnancy may prevent these adverse effect on the intellectual development of infants and children.

It is thought that around 45% of the population of continental Europe continues to show evidence of iodine deficiency despite a lot of work aimed at increasing intake. The main measure put in place to increase iodine intake is through iodisation of salt.

The current recommendation for salt iodisation is that it should be fortified at a level of 20-40ppm. This is based on the assumption that the average salt intake at a population level is 10g per day. The World Health Organisation however recommends that this level will no longer be valid due to public health policies working to reduce population salt intake to 5g per day. They therefore recommend that iodine levels be adjusted in order to take this into account.
CASH acknowledges that iodine deficiency is a potentially serious problem in the UK, particularly in teenage girls and in unplanned pregnancies. However, we are concerned about the public health implication of using iodized table salt as the solution.

In the UK we are currently consuming far too much salt; an average of 8.6g/day compared to the maximum recommendation of 6g/day. Our current high salt intake is responsible for many thousands of deaths and disability from strokes, heart attacks, heart failure and kidney disease each year. The UK is currently leading the world with salt reduction which is crucial if we are to reduce the number of premature cardiovascular deaths worldwide.
There is currently significant progress being made to reduce the salt intake of the UK population, with the food industry voluntarily reducing the amount of unnecessary salt that they add to processed foods. There is also work to increase consumer awareness about the issues surrounding salt and to encourage people to reduce the amount of salt they add in their cooking or at the table.

Using table salt as a vehicle for carrying iodine is, in our view, not sensible as it requires us to put something that is potentially good into something that is known to be bad for our health. We feel that, given the high intake of salt we have in the UK and the progress that is being made, making salt beneficial to our diet is a conflict in public health. If people are aware of their need to increase iodine consumption we do not want them to think that increasing their intake of table salt is the answer. More than anything this is a confusing message for consumers.

Further difficulty comes when deciding to what extent salt should be iodised. Clearly when we are working towards reducing our salt intake to less than 6g per day by 2015 (5g worldwide) this lower amount needs to be taken into account rather than the current high intakes.

The WHO reports that alternative delivery methods of iodine include bread, water, milk, and possibly edible oil and wheat fl our. We feel that these alternative options are preferable and should be investigated by the Department of Health. Iodized bread has been successfully implemented in Australia and Holland. In this case iodised salt has been used in the bread.

References

Vanderpump MPJ, Lazarus JH, Smyth PP, Laurberg P, Holder RL, Boelaert K, Franklyn JA. Iodine status of UK schoolgirls: a cross-sectional survey. The Lancet. 2011. 377 (9782) 2007-2012

World Health Organisation: Salt as a vehicle for fortification. A report from a WHO expert consultation. 2007.