Plants do not need iodine, but humans require it for the production of thyroid hormones which regulate the basal metabolic rate (BMR) of the body. Enlargement of the thyroid gland (goiter) develops when there is not enough iodine to manufacture the thyroid hormones. The gland enlarges in an attempt to trap more iodine. Supplemental iodine in small quantities usually resolves this problem, but thyroid hormone supplementation may be needed.
Even though commercial table salt has had iodine added to deal with this once common deficiency, iodine deficiency is still a problem, and many people in the United States have goiter. Cretinism occurs when iodine deficiency occurs early in life and is characterized by irreversible mental retardation and other problems. It may be present in iodine-deficient babies or children born to women who are lacking iodine.
The body contains only about 25mg (that is 25,000mcg) of iodine. Since iodine is not conserved by the body as with many other minerals, it must be obtained regularly from the diet. Iodine is well absorbed from the stomach into the blood and excessive iodine is eliminated rapidly through the kidneys.
Fish, shellfish, and seaweed are dependably rich sources of iodine. Kelp is an especially concentrated source of iodine. It is also rich in other minerals and thus is a good seasoning substitute for salt. Sea salt is a natural source of iodine, although it is not nearly as high in this mineral as "iodized" salt. Iodized salt contains about 75mcg (.075mg) of iodine per gram of salt. The average person consumes at least 3 grams of salt daily, thus exceeding the RDA for iodine of 150mcg. More iodine is needed during pregnancy and lactation and those on low-salt diets may need supplemental iodine.
The iodine content of a particular food may vary widely depending on the iodine content in the soil in which it grows. Plants grown or animals grazed on iodine-rich soil will contain substantial amounts of iodine. Foods that may contain iodine, especially when the soil is good, are onions, mushrooms, lettuce, spinach, green peppers, pineapple, peanuts, cheddar cheese, and whole wheat bread.
Even though getting the RDA for iodine, some people seem to have more energy consuming more than the minimal amount needed to prevent goiter. Iodine has also been used to help increase energy level and utilization in cases of fatigue, mental sluggishness, and weight gain caused by hypothyroidism. Iodine itself will not help with weight loss if there is normal thyroid function.
Potassium iodide has been used medicinally for problems of the skin and as an expectorant for bronchial congestion. Iodine supplements are also used to help prevent the uptake of radioactive iodine if it is present in the environment. When the thyroid is saturated with iodine, there is less radioactive iodine uptake and greater elimination of it from the body.
There is no significant danger of toxicity of iodine from a natural diet, though some care must be taken when supplementing iodine or using it in large doses. A regular elevated intake of iodine is needed to produce toxicity. Some people have allergic reactions, mainly as skin rashes, to iodine products. Iodine supplementation is known to worsen some acne cases. Taking large doses (50-100mg) regularly can cause a thyroid storm (hyperthyroidism) in some individuals.
The main function of the iodine is synthesis, storage and secretion of thyroid hormone. What iodine is left over is taken up in other tissues especially extracellular fluids and excreted in the urine. From extracellular fluids iodine travels in the lymphatics and re-enters the blood stream via the main lymphatic channel, the thoracic duct. In the 1960s it was established that if the daily dose of iodine was increased to over 2-3mgs (2000-3000mcg) of iodine per day, within two weeks, the thyroid became saturated and no longer took up iodine in significant amounts. So a normal person who raised their daily dose of iodine above, say 3 mgs, within two weeks their thyroid would almost completely stop taking up iodine as it became saturated, but more important to the body, all of the dietary iodine then went to perform other body functions.
In the 1960s (in the US) mandated iodine containing dough was equivalent to the RDA of 150mcg per slice of bread. Your average diet in 1960 contained about one mg of iodine per day, with bakery products providing 726 mcg. This amount was enough to significantly reduce your thyroid glandís ability to absorb radioactive iodine. It also was enough to lower excess thyroid hormone release, preventing hyperthyroidism. And it would provide more availability of iodine for your breasts or prostate.
Then it was withdrawn for fear of adverse effects from too much iodine (Iodophobia). It is very difficult to get too much iodine from food. But to make matters worse, the food industry decided to replace the iodine with bromine in many instances.
At that time the incidence of breast cancer was only 1 in 20. In the past 20+ years the use of iodine supplementation in bread was eliminated and a goiter producing substance toxic to the thyroid gland (bromine) was introduced as replacement for iodine. The risk for breast cancer is now 1 in 8 and this risk is increasing by one percent each year. The decision to replace iodine in an iodine deficient population with a goitrogen was illogical and lacking in common sense. The damaging effects of bromine on thyroid tissue also appears to contribute to the development of auto-immune diseases in the thyroid gland (Hashimoto's thyroiditis).
Switzerland, Germany and New Zealand have already decided to act to add iodine to foods. Australia is going to add it to bread again, after discontinuing it's addition for some years.
Nearly every physician in the United States will reach for a prescription pad to order thyroid hormone when he sees a patient with goiter or symptoms of hypothyroidism. This can be exactly the wrong thing to do if the patient has deficient stores of iodine. Insist on obtaining a 24 hour urine collection for iodine to eliminate iodine lack as the cause for your symptoms (values below 50 ug/liter are abnormal). Thyroid hormone therapy in the presence of iodine deficiency increases the risk of breast cancer and probably thyroid cancer as well. Endocrinologist, Dr. Guy Abraham, formerly of the U.C.L.A. Department of Endocrinology, is convinced that everyone needs to be on iodine therapy until their iodine stores have been fully restored. After this time frame periodic intake of iodine will help insure that the many body functions requiring iodine run smoothly.
Some holistic doctors feel that no more than one dose per day of Iodoral should be used without supervision. Others suggest a dosage of two tablets of Iodoral twice daily for three months followed by one Iodoral tablet daily for a year will restore iodine stores for most persons. At that point periodic taking of an Iodoral tablet daily one month out of 4 to 6 months etc. will be adequate to maintain iodine stores. Iodine stores can be easily monitored by taking 4 Iodoral tablets (50 mg iodine) and collecting a 24 hour urine sample for iodine content. If 80% of the ingested iodine is found in the urine collection the iodine stores are normal. Iodoral can be obtained from Optimox Corp. Torrance, Cal. To purchase a referral from a health care practitioner is needed.
SSKI (Super-Saturated Potassium Iodide) can be obtained without prescription in some compounding pharmacies, some health food stores, through online sources. This form of iodide has many practical uses, and can be used both topically and orally.