Op-Ed: Iodised salt in bread is a good way to tackle Iodine deficiency disease
by Lianne Dalziel, Minister for Food Safety
It's unbelievable that history has repeated itself and New Zealanders are again facing significant iodine deficiency.
Worse, we're reverting to a level of iodine deficiency that existed prior to the elevated iodisation of salt in New
Zealand in 1938. How has this happened and what's being done about it?
The New Zealand Food Safety Authority (NZFSA) this week announced it will be mandatory to replace non-iodised salt with
iodised salt in commercial bread as a cheap and effective way of boosting iodine intake in our diet, and this to me
seems a sensible solution to the problem.
Before iodised salt was introduced in 1924, and then the iodine content increased to more effective levels in 1938, it
is thought that about two thirds of school children suffered from iodine deficiency. This problem virtually vanished for
the decades following and we largely forgot all about it. But, a study published in 2002 which measured the iodine
status of school children in Wellington and Dunedin in the 1990s, indicated that up to 80 percent of them once more had
some level of iodine deficiency.
When I was a high school student in the 1970s I remember learning about the problems caused by lack of iodine. I'd seen
pictures of people with goitres on their necks, the large swelling caused by iodine deficiency disease which enlarges
the thyroid gland. Fortunately by then, in New Zealand they were largely a thing of the past. But the more damaging
effect of iodine deficiency is on the developing brain. The World Health Organisation says iodine deficiency is the
world's greatest single cause of preventable brain damage and mental impairment. Despite increased access to iodised
salt around the world over the past decade, WHO says that in 54 countries the intake of iodine is still insufficient and
that a third of the world's school age children don't get enough iodine. So, the impact of iodine deficiency on health
and development remains a serious global public health concern.
Iodine leaches easily from the soil, especially in rainy climates like New Zealand's, so it's not available in
sufficient quantities through the plants and animals that we eat. Because the soluble iodine is deposited into the
ocean, seafood and seaweed are enriched by it and are the best natural food sources. Iodine is also found in eggs and
dairy products. Ironically, the amount found in our milk has actually dropped over the past 20 years since New Zealand's
dairy industry stopped using iodophors as sanitisers for milking equipment. It is thought that "contamination" by these
iodophors may once have been a significant source of iodine in our milk.
Humans need only a miniscule amount of iodine over a life time, but we have to ingest micro amounts on a regular basis.
That's why iodising salt was such a good idea, because it's a basic food ingredient that most of us use daily. It's good
news that the public is taking in the important health message that too much salt carries risks of cardio-vascular
disease, and people should continue to reduce their overall salt intake. But an unintended consequence has been a drop
in the amount of iodine ingested. This trend has been exacerbated by the increasing use of sea salt, rock salt and flaky
salt which do not contain iodine.
Australian and New Zealand Food Ministers have accepted the proposal that the best fix available is to make it mandatory
for bread manufacturers to replace non-iodised salt with iodised salt in bread. It's a simple, low-cost way of
increasing the iodine levels in our diet. It doesn't impose extra effort or cost on bread manufacturers who already add
salt, and consumers will still have choice because organic products and unleavened bread such as pita and tortilla are
exempt.
Bread manufacturers have until September 2009 to switch to using iodised salt. That gives them time to make changes to
manufacturing and labelling and it will allow the salt industry time to increase the production of iodised salt.
There's more information about iodine on the New Zealand Food Safety Authority's website at: www.nzfsa.govt.nz under the
Consumers tab.
We are lucky to live in a country where there is a variety of healthy food available to us, but even when eating a
balanced diet it can be difficult to get enough iodine in New Zealand. This is a move that will bring us back from the
brink of a return to early 19th century health problems.
ends