Nutrition information
Iodine
The main function of iodine is to make thyroid hormones, which control metabolic processes (normal growth and development) and normal metabolic state (body temperature/metabolic rate).
Iodine deficiency
The low levels of iodine present in the soil and environment in New Zealand
are reflected in the low levels present in plant foods. This translates
into a higher risk that people will suffer from iodine deficiency. Symptoms
of deficiency are fatigue and swelling of the thyroid gland in the neck,
called goitre. Low-iodine diets can retard children's mental and physical
development and make people tired, overweight and constipated. In the
1920s salt was fortified with iodine as a way of tackling the goitre endemic
occurring at the time.
Iodised salt
Although today 70% of the salt used is iodised, many people have reduced
their use of salt due to the risk of increased sodium intake leading to
cardiovascular disease. People are also regularly eating more prepared
meals or processed meals but the majority of the salt used in food industry
is not iodised. The dairy industry has moved away from using cleaners
which contained iodine. Rock salt which does not contain iodine, has also
become more popular.
Food sources of iodine
Although it is advisable to limit salt intake, when using salt make sure
it is iodised to ensure an adequate daily intake of iodine. Include other
sources of iodine in the diet, such as seafood, fish, eggs and low-fat
milk products. Supplements for iodine should only be used if recommended
by a health professional, as high levels of iodine can be toxic and lead
to adverse health effects.
Iodine fortification
Food
Standards Australia and New Zealand (FSANZ), the organisation that
develops food standards to ensure safe food, currently preparing draft
standards on the addition of iodine to foods to avoid the occurrence of
iodine deficiency disorder (IDD). The main objective of this standard
is to determine the most effective mechanism to improve iodine status
of Australians and New Zealanders.
At greatest risk of IDD are pregnant women and their unborn child, as well as women of child-bearing age. Iodine is the most important cause of preventable brain damage and mental retardation in fetus.
One of the difficulties for FSANZ is determining what food should be used as the vehicle for iodine fortification. The food item/group chosen for fortification would need to be regularly consumed in predictable amounts, be cheap and store well. Although there are currently regulations in place for the fortification of salt with iodine, it is thought these requirements are no longer enough to ensure an adequate intake amongst New Zealanders.
One option is to increase the amount of iodine added to salt. It is questionable whether this would be effective as the amount of salt added to foods in the home is decreasing and the food industry predominantly uses non-iodised salt in processed foods.
Another option is the fortification of bread with iodine. As bread is a staple of the New Zealand diet, this could substantially increase iodine intake. A balance is required between ensuring that at-risk groups receive enough iodine, but that other groups in the community do not receive too much. Over-consumption of iodine can cause iodine toxicity, which, like deficiency of iodine can also lead to goitre.
Some consumers also believe that their food should not be fortified so their views need to be taken into consideration. The Bread Industry has opposed mandatory fortification of all bread as their research shows many consumers oppose not being able to make this choice on whether the bread they are consuming is fortified. Instead the Industry proposes fortifying a number of breads targeted at those at risk of the consequences of a low-iodine diet.
Public submissions for the fortification of foods with iodine closed on the 23 February 2005 and now a draft assessment is being prepared by FSANZ which will again be reviewed by the public and food industry. It is likely to still be some time before fortification of foods with iodine becomes law.
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