Brain damage alert as iodine levels fall

Universal salt iodisation may be introduced in New Zealand as low iodine levels are making New Zealanders susceptible to goitre and brain damage, experts say.

Iodine deficiency is the leading cause of preventable brain damage in children and also causes goitre and stunted growth.

The Food Safety Authority says iodised salt, once the nation's primary iodine source, is increasingly falling out of favour due to decreasing salt consumption and the popularity of rock and sea salts.

The problem has been compounded because New Zealand's soils are naturally low in iodine and foods grown in them are low in iodine.

A 2002 children's nutrition survey revealed one third of New Zealanders were iodine deficient.

The authority's assistant director, Jenny Reid, said mandatory iodine fortification of food was the favoured option to ensure New Zealanders consumed adequate amounts of iodine.

She said Food Standards Australia New Zealand was considering universal salt iodisation and the iodisation of flour, bread or milk as possible ways to get more iodine into our diet.

"It's got to be the thing that everyone has the potential to get."

Universal salt iodisation would result in iodised salt being included in all processed foods.

Although the authority preferred mandatory measures, voluntary options for industry were also being considered, Ms Reid said.

The voluntary option could lead to industry producing expensive "designer" iodised foods or even a surfeit of iodised products, which could lead to income-based inequalities and public health risk.

"Mandatory [fortification] allows more control over what's going into the food supply - it's much more equitable if it's across a range of food that everyone can buy," Ms Reid said.

Consumers would still have the choice of buying those products or not.

The significant risks to children and the unknown impact of iodine deficiency on their lives meant it was vital to get our iodine levels up to those of other countries, she said.

Medical Association chairman Ross Boswell said it was important New Zealanders received a regular and adequate iodine intake.

Besides the risks of brain damage and goitre from insufficient iodine, a fluctuating iodine intake could lead to fatal thyrotoxicosis - a result of too much iodine.

Dr Boswell said "fashion" and "naturalist" ideas led some people to avoid iodised salt, but natural iodine-rich options such as kelp or seaweed could also lead to iodine overdoses.

Iodisation of salt had worked well in the past, he said. "I personally would prefer education rather than regulation ... People should take iodine because they know it's good for their health."

Safe Food Campaign co-convener Jacky Pearson said the campaign did not usually favour adding nutrients to foods, but the short supply of iodine made this more difficult to rule on.

"Iodine is probably all right because it can be put in food in a natural form," Mrs Pearson said.

Institute of Food Science and Technology president Sally Hasell said the industry would look at using iodised salt if it became an imperative.

Iodised salt was at present unavailable in large enough quantities for industry to use, Dr Hasell said.

- NZPA