Iodine. Metabolic control, modulation of oestrogen and foetal
is commonly known to have a major effect on thyroid function,
being a main component of the thyroid hormone thyroxine.
However, Iodine has many other effects, from controlling
the effects of oestrogen on breast tissue to protecting
against the effects of radioactivity.
has been a favourite with those who want to lose weight
for many years. As stated above, iodine is the main component
of thyroxine, the thyroid component which controls metabolism.
As metabolic rate controls the amount of "fuel" burned
by the body for energy, iodine deficiency can result in
a decreased metabolic rate, hence the supplementation by
the other key functions of iodine is in the formation of
the foetal nervous system. If the mother is deficient,
there is a significant chance of the baby being born with
cretinism (extremely low intellectual capacity). Iodine is
also an important component of healthy connective tissues.
Research suggests that iodine is involved in moderating
the effects of oestrogen on
breast tissue. This seems to be particularly important in
fibrocystic breast disease,
iodine has been shown to be of some use in overcoming the
problem. given the role of oestrogen in breast cancer, their
may be some part played by iodine here too.
widely known source of iodine is kelp, however it is also
found in fish and, of course, iodised salt. Plant sources
of iodine are totally dependant on where the plant is grown,
due to the issue of depleted
Functions of Iodine in the body
- Required for manufacture of thyroxine (and therefore
control of metabolic rate)
- Essential to the normal development of the foetal nervous
- May protect against the effects of radioactivity
- Can regulate the effects of oestrogen on breast tissue
- A required component of healthy connective tissue
to the introduction of iodised salt, iodine deficiency
is now rare in the Uk and USA, although it does still occur
in parts of Europe. Goitre, or enlargement of the thyroid
gland, is the most common sign of deficiency. It is thought
to affect over 200 million people worldwide and up to 6%
of the population in areas with iodine deficient soils
in the USA.
Deficiency itself may not be indicative of a lack of iodine
in the diet, as many things can reduce iodine absorption
or, more commonly, iodine utilisation in the thyroid. Such
substances are called goitrogens and are listed under "factors
affecting iodine levels".
of Iodine deficiency
Goitre (swelling of the thyroid gland)
Reduced immune system function
Excessive oestrogen production
Possible links to Parkinson's disease, multiple sclerosis
and Alzheimer's disease.
affecting iodine levels
from iodine intake, a number of factors can affect iodine
levels. minerals such as calcium,
manganese, magnesium and fluoride are
all goitrogens, which restrict iodine uptake
by the thyroid. Goitrogens are also present in :
However the goitrogens present in such foods can be largely
inactivated by cooking. Tea then becomes the exception and
drinking large amounts of tea will definitely affect iodine
absorption and usage.
Normal amounts of Iodine in the diet
|11yrs+ (inc adults)
Sources of dietary Iodine
|Canned corned beef
Iodine is also present in plants, however its presence is
totally dependent on the availability of iodine in the soil,
which is hugely variable from one area to another, due to
the issue of depleted soils.
Two main forms of supplement are available, namely Iodine
and iodides. Iodine compounds seem to be largely responsible
for the effects of iodine on the role of oestrogen in breast
tissue and are preferable. Iodides, on the other hand,
seem to have more of an effect on thyroid function.
At large doses (greater than 750mcg) iodine supplements
have been shown to reduce thyroid secretions, which should
be considered by those who are trying to control their weight.
At very high doses, iodine is toxic.
Back from Iodine to minerals
Essential fatty acids