Iodine
Other name(s):
iodide, organic
iodine, potassium iodide, sodium iodide
General description
Iodine is an essential mineral
element. It is naturally found in some foods, and added to other foods. It can also
be
taken as a supplement. In 1922, experts learned that the thyroid gland needs iodine.
The
gland needs it to make thyroid hormones and prevent enlarged thyroid glands (goiter).
Thyroid hormones control metabolism. They also affect reproductive functions, nerves,
muscles, skin, and hair. Iodine also helps make protein and use oxygen.
Iodine is in 2 main hormones made
by the thyroid gland. Together, these hormones control the metabolic rate of the body.
They’re important in growth and development, especially in an unborn baby and a newborn.
Not having enough iodine and thyroid hormones can cause intellectual issues and
developmental delays.
Medically valid uses
Iodine is used to prevent and
treat:
Using table salt that has potassium
iodide can help prevent goiters. Other sources of iodine include eggs, dairy foods,
and
seaweed.
If you get goiter during pregnancy,
you’ll need treatment. This can keep your baby healthy.
Unsubstantiated claims
There may be benefits that have not
yet been proven through research.
Iodine may help immune response.
And it may have a helpful effect on mammary dysplasia and fibrocystic breast
disease.
Recommended intake
Many areas of the country have very
little iodine in the soil. As a result, crops in these areas and animals raised on
these
crops are not exposed to much iodine. Before iodine was added to table salt, many
people
in these areas had goiters. The Lake Michigan area was once called the “goiter belt.”
This problem has mostly gone away now. This is likely because of iodized salt and
the
widespread consumption of ocean fish and shellfish.
But people living in areas without
enough iodine in the soil may still need iodine supplements. This includes people
living
in the Great Lakes states and mountain regions of the United States and Mexico.
Adults who don’t get enough iodine
in their diet can get goiters. In severe cases, this may lead to an underactive thyroid
gland (hypothyroidism). Symptoms can include:
People who consume large amounts of
soy, cassava, or uncooked cruciferous vegetables also need more iodine. These include
cabbage, cauliflower, broccoli, kale, Brussels sprouts, and rutabagas. These foods
have
substances that keep the digestive tract from absorbing iodine. Cooking stops the
action
of these substances.
Newborn babies that don't get
enough iodine in the womb are often born with enlarged thyroid glands. They may also
have signs of hypothyroidism. If a baby's thyroid doesn’t work during growth in the
womb, he or she can get congenital hypothyroidism. This can lead to intellectual issues.
It can also cause growth problems.
Iodine is measured in micrograms
(mcg). The Recommended Dietary Allowance (RDA) is as follows:
|
Group
|
RDA
|
|
Infants (0 to 6
months)
|
110 mcg*
|
|
Infants (7 months to
1 year)
|
130 mcg*
|
|
Children (1–3
years)
|
90 mcg
|
|
Children (4–8
years)
|
90 mcg
|
|
Children (9–13
years)
|
120 mcg
|
|
Males (14 years and
older)
|
150 mcg
|
|
Females (14 years
and older)
|
150 mcg
|
|
Pregnant women
|
220 mcg
|
|
Breastfeeding
women
|
290 mcg
|
*Adequate Intake (AI)
|
Food source
|
Nutrient content per
100 grams
|
|
Seaweed
|
61,990 mcg*
|
|
Iodized salt
|
10,000 mcg
|
|
Cod liver oil
|
838 mcg
|
|
Seafood, fish
(depending on type of fish)
|
36–311 mcg
|
|
Seafood, shellfish
(depending on type of shellfish)
|
31–129 mcg
|
|
Sea salt
|
94 mcg
|
Iodized salt contains potassium iodide. It’s often in a ratio of 1
part iodine to 10,000–100,000 parts salt. This means there’s very little iodine in
the
salt. But it’s enough to prevent goiter. Iodized salt made in the U.S. contains 76–100
mcg of iodine per gram of salt.
Side effects, toxicity, and
interactions
Elemental iodine is toxic. This
type is found in tincture of iodine. It’s used to disinfect cuts. Swallowing even
a
small amount can cause death.
Getting too much iodine may also
cause problems. It can also cause a goiter. It may also keep your thyroid from working
well. This is more likely if you take doses close to 1,000 mcg per day.
Women who are pregnant or
breastfeeding shouldn’t take iodine supplements without talking to their healthcare
providers. Too much iodine in pregnancy may cause hypothyroidism and a goiter in a
newborn.
Talk with your healthcare provider before taking iodine if you take
any of these medicines: