Should we now put iodine in salt to boost babies’ IQ?

As folic acid’s finally added to flour...

THE Government’s plan to add folic acid to bags of flour marks a successful end to a 25-year campaign by diet experts. The nutrient is essential during pregnancy to prevent birth defects, and the move will bring Britain into line with 100 other countries, including the US.

One in five young women don’t get sufficient amounts of folic acid in their diet, which is found in leafy green veg and prevents potentially life-threatening conditions of the brain and spinal cord in newborns. Adding it to flour – and therefore the huge range of foods that use it, such as bread – is expected to prevent hundreds of cases a year.

But while experts have welcomed the move by the Government, they also say it is only part of the solution for preventing birth defects in thousands of babies every year. Campaigners are now calling for iodine to be added to foodstuffs, especially salt, claiming the nutrient is just as crucial for both mother and baby as folic acid, if not more so.

Iodine is a black hued mineral that is abundant in fish, milk, eggs and, oddly, seaweed. It’s essential for the growth and maintenance of the thyroid gland – a butterfly-shaped organ in the neck that controls a host of essential functions, including helping turning food into energy and maintaining body temperature.

In adults, iodine deficiency stops the thyroid functioning properly, causing weight gain, extreme body temperatures and other problems. But more serious are the implications for unborn babies. A mother’s malfunctioning thyroid in early pregnancy can halt the development of the foetus’s brain, which increases the risk of learning and behavioural disorders in later life and, in severe cases, premature and stillbirth.

LONG-TERM studies show that babies born to mothers with low iodine levels are, on average, two IQ points below their peers when they reach older childhood. While roughly 20 per cent of maternal-age women are deficient in folate – the naturally occurring form of vitamin B9, of which folic acid is the synthetic supplement – twice as many fail to get sufficient iodine from their diet, the Government’s latest National Diet And Nutrition Survey suggests.

According to the British Dietetic Association, the average adult needs roughly 150 micrograms of the mineral daily – the amount in approximately two large glasses of milk – while women who are pregnant or breastfeeding need 200 micrograms.

And as more people adopt a vegan diet, the problem is set to get worse. The number of Britons ditching meat and dairy, both key sources of iodine, quadrupled between 2014 and 2019. In the UK in 2016, the Vegan Society found that twice as many women as men were vegan, while in the US, 79 per cent of vegans are female.

Last year a small German study involving 36 vegan adults found a third had levels of iodine considered severely deficient.

Supplements can help, but it can be tricky to manage the dose, as too much can risk the overdevelopment of a baby’s thyroid gland which can interfere with breathing. But a growing number of specialists say there is another solution. At the end of 2019 a group of experts from Croydon University Hospital in London and the British Thyroid Foundation published a report in The Lancet medical journal calling for ‘urgent corrective strategies’, including adding traces of iodine to salt.

This is in line with the World Health Organisation’s recommendations to fortify all salt used in food processing, as putting it in a common ingredient would bolster levels ‘by stealth’.

Experts suggest that fortification may also reduce the risk of inadvertently overdosing on the mineral, as women will not have to rely on supplements. Many countries have taken note over the past two decades, making most salt products iodised.

Dr Sarah Bath, a dietician and researcher in iodine deficiencies at the University of Surrey, says: ‘Iodine doesn’t change the taste of salt, which is the reason why other countries have chosen to add the mineral to it.’

‘Since 2009, Australia and New Zealand have used iodised salt in a large number of bread products, and boosted iodine intake in a relatively short space of time without consumers even being aware of it.’

In China, 97 per cent of salt has been iodised since the early 90s. The nation has since seen a dramatic improvement in the cognitive development of children, according to the World Health Organisation.

‘The UK policy is madness and decades behind the rest of the world,’ says Dr Malcolm Prentice, a consultant endocrinologist and a campaigner for The UK Iodine Group. ‘What have we got to lose by fortifying salt? It’s a minimal risk intervention for huge benefit for the entire population.’

So why is UK health policy not addressing this?

‘One problem is that the effects of iodine deficiency aren’t as obvious as they are with folate,’ says Dr Julie Abayomi, who sits on the British Dietetic Association’s maternal and fertility nutrition group.

‘Most people recognise iodine deficiency in its most extreme form – where swellings develop in the neck.

Thankfully it’s not that extreme these days, but it means some think it doesn’t exist any more.

‘In many cases, the effects on cognitive development aren’t seen until several years after the baby is born, so circumstances at birth aren’t explored as a potential cause.’

It is difficult to prove the impact of global iodised salt programmes due to the many other, unknown factors that can cause abnormal foetal brain development, and other effects on cognitive development throughout life, such as parental education and social class.

The UK policy is madness… decades behind the rest of the world

HOWEVER, several global analyses have shown a marked increase in the IQ of children and economic growth that coincides with the introduction of national iodisation programmes.

‘It’s a case of, why not fortify?’ says Dr Abayomi. ‘There are plenty of factors that influence cognitive ability that we can’t do anything about, but iodine intake is something we can easily control.’

In the meantime, experts say there’s something food manufacturers could do: fortify vegan ‘milks’. In 2017, Dr Bath and colleagues analysed 47 milk-alternatives, including soya, oat and rice milk, and found just three were fortified with iodine. Most contained less than two per cent of the iodine in cow’s milk.

‘We’ve always thought we had enough iodine in our diets, but there’s increasing evidence some may be deficient,’ says Dr Bath. ‘With changing dietary patterns, we need to adapt and make sure there are sources of iodine for everyone.’