Someone just forwarded this to me. It mentions the formation of the ear
structures. I wonder about the process of breastmilk production also.
Judy Ritchie


Sunday Telegraph (Australia)
July 16, 2006.

Are you getting enough iodine?

By Joanna Hall
A new study has discovered that many Australian school children are mild to
moderately iodine deficient. But what is iodine, and why is it so important?
Say the word "iodine" to most people and what's likely to spring to mind is
that dark brown liquid your mum used to clean and disinfect your childhood
scrapes and scratches. But iodine isn't just an effective bug killer.
It's an important micronutrient essential for hormone development in the
human body - and one which Australian researchers say we're not getting
enough of.
In February this year, the National Iodine Nutrition Study indicated that,
overall, Australian children are borderline iodine deficient.
A team of researchers, led by endocrinologist Professor Creswell Eastman,
surveyed the iodine levels of 1709 children from 88 schools in Australia.
The study found that children in NSW and Victoria are mildly iodine
deficient, while those in South Australia are borderline.
Children in Queensland and Western Australia were pronounced iodine
sufficient, and Tasmania was excluded from the study because a voluntary
iodine fortification program - using iodised salt in bread - is ongoing
there.
So why the concern?
Professor Eastman, who is chairman of the Australian Centre for Control of
Iodine Deficiency Disorders and deputy chairman of the International Council
for the Control of Iodine Deficiency Disorders, explains: "Iodine has one
function in the human body: as a building block to make thyroid hormones."
Thyroid hormones are produced by the thyroid gland, located at the base of
the front of the neck.
"These hormones are some of the most important and powerful in your body,"
says Professor Eastman.
"They control metabolism, growth and, in a foetus and newborn infant, they
control brain growth and development."
A diet lacking in iodine is associated with a wide spectrum of health
problems, collectively known as iodine deficiency disorders or IDD.
They can impact on people of any age, with the most visible and well known
being an enlarged thyroid gland, called a goitre.
But iodine deficiency has the greatest impact on unborn and newborn babies,
as it can impair normal brain development.
"If adults don't get enough iodine, they may grow a goitre and not feel
well, but this can be reversed by increasing their iodine intake," says
Professor Eastman.
"But in foetuses and newborns the effects are irreversible."
The recommended daily intake (RDI) of iodine is 120 micrograms for women and
150 micrograms for men. Pregnant and breastfeeding women need between an
extra 100 to 200 micrograms a day.
"A developing foetus requires the mother to pass thyroid hormones across the
placenta to ensure the baby's brain develops and matures normally," explains
Professor Eastman.
"There are critical times for various parts of the brain in an unborn foetus
to form.
"For example, the basic structures for hearing occur midway through
pregnancy. So if the mother isn't getting enough iodine, she won't have
enough thyroid hormones to pass on.
"As a result, those hearing structures won't form properly, and the baby
will have a form of nerve deafness, which may be very mild or severe, or
even complete."
Deficiency is also a postpartum problem; if a new mother is iodine
deficient, her breast milk will also be deficient.
Iodine deficiency also impairs the development of motor skills, and even IQ.
"If you don't have enough thyroid hormones, your intellectual function will
be impaired," says Professor Eastman.
"The greater the problem, the greater the IQ loss. We can show that if
iodine deficiency is severe, you lose 15 IQ points on average - that's a
massive loss."
The amount of iodine a person requires in a lifetime amounts to only a
teaspoon - the daily RDI is calculated in micrograms, which is one millionth
of a gram.
But because the body cannot store iodine, a tiny amount has to be consumed
every day.

But if we need so little iodine, why is getting enough such a problem?
"Surprisingly few foods are good sources of iodine," says nutritionist
Catherine Saxelby.
"The best dietary sources are seafood, fish and seaweed such as kelp and
nori. Meat, eggs and dairy give us tiny amounts, and with vegetables and
grains it largely depends on where they're grown and whether or not the soil
was iodine-rich."
Professor Eastman's team believes the national iodine deficiency has come
about for two major reasons. One is a drop in the level of iodine in milk.
From the 1960s, dairy farmers used iodine to sterilise milk containers,
inadvertently adding the element to our milk supply. But in the past decade,
these sterilising products have been replaced by ones containing chlorineor
other acid-based chemicals.
There has also been a drop in the consumption of iodised salt, due to people
reducing their overall salt intake and to the trend towards using sea or
gourmet salts, which are not iodised and contain little or no natural
iodine.
As well as eating more fish and seafood, supplements are an option for
vegetarians and pregnant and breastfeeding women.
Several multivitamins contain iodine (in the form of potassium iodide),
though doses vary. Or you can take kelp tablets.
Blackmores has multivitamins with iodine for women, men and children in its
range.
Earlier this year it launched I-Folic, with iodine and folic acid, for women
planning pregnancy, as well as a campaign to raise awareness of the lack of
iodine in the Australian population.
Anyone planning to take iodine supplements, however, should see a doctor.
Too much can be toxic, especially for people with certain thyroid disorders.
Professor Eastman's study has prompted calls for mandatory iodisation of all
edible salt in Australia, and Food Standards Australia New Zealand is
currently reviewing this.
"We're not encouraging people to eat more salt, just the right kind of
salt," explains Professor Eastman.
"In foetuses and newborns the effects are irreversible ... If iodine
deficiency is severe, you lose 15 IQ points on average - that's a massive
loss"

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