Iodine

Thyroid disorders are one of the most frequently undiagnosed health problems that affect women. A lack of iodine in the diet can seriously impair the workings of the thyroid gland and many women just don't get enough from their diets. Naturopath Michael van Straten serves up a fishy solution to this widespread problem.

Iodine is an essential trace element which is needed in tiny amounts in order for the thyroid gland to produce thyroid hormones. These complex substances control many of the body's most important functions and lack of this nutrient can seriously affect the health of adults and children. Fish, shellfish and seaweeds are the only major sources of iodine and the amounts in other foods depend entirely on the iodine content of the soil in which crops are grown or on which animals graze.

Some table salt has added iodine though as people become more aware of the dangers of excessive salt this becomes a less valuable source. If you use sea salt it will contain some iodine but unfortunately a lot of it is lost during storage. During the winter months milk can be a good source of this mineral as most commercial cattle feed is enriched with iodine to prevent stillbirth and thyroid problems. Much of this added iodine ends up in cow's milk but once the cattle are turned out to graze the level falls substantially, especially where there is little naturally occurring iodine in the soil.

The body extracts iodine from food and stores it in the thyroid gland for the manufacture of thyroid hormone. Once its job is done the remaining iodine is filtered by the kidneys and removed in urine. If you are losing more than you're getting out of your food the thyroid gland grows in size to try and capture more of the iodine circulating in your blood. As a result a swelling appears at the front of the neck, where the thyroid gland is situated, causing the medical condition ‘goitre'. This used to be known as ‘Derbyshire Neck' because the local soil is severely deficient in iodine and goitre was very common throughout the county.

Iodine is very important during pregnancy as even if the thyroid enlarges in an attempt to produce more hormone there may not be enough for mother and developing baby. This deficiency can lead to poor brain development and serious health problems. Both vitamin A and selenium are important for the most efficient absorption of iodine and if there is not enough of these nutrients in your diet you may be making too little thyroid hormone. Some vegetables like raw cabbage, spinach, turnips, kale, and some drugs like lithium antidepressants and anti-diabetic medication, can also interfere with the body's uptake.

Lethargy, weight gain, cold extremities, swelling in the front of the neck, and difficulty in concentrating can all be caused by iodine deficiency but taking iodine supplements should only be done on the advice of a professional practitioner. Too much iodine can overstimulate the thyroid and cause palpitations, anxiety, insomnia and weight loss. For this reason great care should be taken before using kelp supplements as they can contain high levels of iodine which are seldom analysed or quantified on the package. The RDA is 150 micrograms daily and few of the diets I analyse contain even 100 micrograms, and often much less. Here are the foods which supply the best amounts.


Kombu Seaweed, dried, raw
440,670 mcg / 100 g
Percentage of daily requirement: 88,134% from average 30 g portion
Iodine score: 10/10

Wakame Seaweed, dried, raw
16,830 mcg / 100 g
Percentage of daily requirement: 3,366% from average 30 g portion
Iodine score: 10/10

Haddock
320 mcg / 100 g
Percentage of daily requirement: 320% from average 150 g portion
Iodine score: 10/10

Mackerel
180 mcg / 100 g
Percentage of daily requirement: 180% from average 150 g portion
Iodine score: 10/10

Cockles
160 mcg / 100 g
Percentage of daily requirement: 106% from average 100 g portion
Iodine score: 10/10

Lobster
100 mcg / 100 g
Percentage of daily requirement: 66% from average 100 g portion
Iodine score: 6/10

Fishpaste
310 mcg / 100 g
Percentage of daily requirement: 62 % from average 30 g portion
Iodine score: 6/10

Whole milk - summer
5 mcg / 100 g
Percentage of daily requirement: 10% from average half a pint portion
Iodine score: 1/10

Whole milk - winter
40 mcg / 100 g
Percentage of daily requirement: 80% from average half a pint portion
Iodine score: 8/10


Eggs
53 mcg / 100 g
Percentage of daily requirement: 35% from 2 eggs
Iodine score: 3/10