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PROMOTES Thyroid Hormones Stable Body Temperature Physical growth Healthy Reproduction Stable Normal Metabolism Healthy Weight
PROTECTS AGAINST Fatigue Low Thyroid Hormones Cold Intolerance Waxy Skin Weight Gain
Recommended Dietary Allowances for Adults range from 150 to 200 micrograms a day.
Overview Iodine is a solid halogen and was discovered in 1811 by Bernard Courtois. He extracted it from seaweed. It is number 53 on the atomic periodic table.
Iodine is considered to be an essential trace mineral. It's only known to be utilized as a component of thyroid hormones. These hormones are diiodotyrosine, triiodothyronine (T3), and thyroxine (T4). Iodine is converted to iodide in the gastrointestinal tract where it is then absorbed and transported to the thyroid gland. It is then stored in the thyroid on tyrosine protein which is part of a protein complex called tyroglobulin until it is needed for production of hormones.
Iodized salt has potassium iodide added and provides the equivalent of about 400 micrograms (mcg) per teaspoon.
Depletion of or insufficient ingestion and/or absorption of iodine decreases thyroid hormone synthesis. Hypothyroid activity can cause theses symptoms:
-Basal Metabolism Slowing -Dry Skin and Brittle Hair or Hair Loss -Fatigue -Constipation -Fluid Retention -Thickening of the Skin -Weight Gain -Depressed Mood -Sleep Disturbance
Disease States:
-Cretinism: Persistent low levels of thyroid hormone during pregnancy can cause cretinism, resulting in both mental and physical retardation.
-Goiter: Enlargement of the thyroid gland can occur from a lack of iodine. This is called simple goiter and can become very large and prominent in the front of the neck. It can be prevented and cured by ingestion of iodine. There are naturally occurring substances in some foods that promote goiter. These are called goitrogens and are contained in raw cabbage, cauliflower, peanuts, soybeans and turnips. Cooking destroys these substances, but if excessive amounts of the raw forms are ingested by iodine deficient persons, goiter is promoted.
-Myxedema: Iodine deficiency is just one cause of this severe hypothyroid state. This condition is life threatening and needs medical intervention and thyroid replacement therapy. It is marked by a very slow metabolic rate with psychomotor slowing, anemia, liver enlargement and abnormal function, fluid retention, thickening of the skin, and/or enlarged tongue with slowing of the speech.
None identified.
Most processing of food is done with salt that usually adds iodine.
The most common source of iodine in the U.S. diet is iodized salt.
Iodine rich foods include: -Almonds -Nutritional Yeast -Seafood, particularly shell fish -Sea vegetables, I.e. seaweed, kelp -Vegetables grown in iodine rich or enriched soil
Iodized Salt
The effects of iodine are those of the thyroid gland hormones. These effects are far reaching. The thyroid hormones regulate basal metabolism, cellular oxygen consumption, and overall energy production in the body. As a result, body temperature, synthesis of proteins, physical growth, and reproduction are dependent upon these.
Thyroid gland suppression or damage will cause it to have alterations in it's production ability, most commonly to under produce or not be able to produce the hormones. There are a number of scenarios where this will happen.
Taking oral thyroid replacement hormone at higher than needed doses will suppress whatever thyroid function remains. There is a complex "feed back" communication system in place to regulate a balance in the hormone levels in the body (see Other Facts). Damage from infection, chemicals, radiation, tumors or the body's own immune system in the case of autoimmune destruction, can adversely alter the regulation of the amount of hormone produced by any of the glands involved in this "feed back " system. This in turn could cause an underproduction or in some cases an overproduction of thyroid hormones and the utilization of iodine.
In a hypothyroid state, the basal metabolism can go down as much as 50%. In a hyperthyroid state, it can more than double causing palpitation, tremor, diarrhea, sweating, and anxiety.
There is a sensitive, complicated communication system between hormones in general and specific hormones in particular that controls and regulates hormone production in the body. This communication system is referred to as negative feedback hormone control.
A decline in serum thyroid hormone levels, occurring for any number of reasons, triggers the hypothalamus gland to release thyroid releasing hormone (TRH). The TRH signals the pituitary gland to release thyroid stimulating hormone (TSH). A rise in TSH stimulates the thyroid gland to take up more iodine, produce more enzymes to cleave thyroglobulin, produce more thyroid hormones, and to release these hormones into the circulation to be transported to the cells throughout the body. Bioavailability of iodine is an integral part of this whole process.
Three clinical trials involving 1551 pregnant women taking iodine supplements were reviewed and shown a marked reduction of early infancy death and incidence of cretinism by age four in areas where there were high levels of cretinism. There also were much better scores on psychomotor and neurological function testing between early infancy and two years of age.
Poor iodine status should be suspected if recurrent bacterial infections occur in the presence of other symptoms of iodine deficiency. This is rare.
Recommended Dietary Allowance: 1989 Recommended Dietary Allowances (RDA) National Academy of Sciences
AGE (YRS) AMOUNT in micrograms
Infants 0.0-0.5: 40 0.5-1.0: 50
Children 1-3: 70 4-6: 90 7-10: 120
Males 11-14: 150 15-18: 150 19-24: 150 25-50: 150 51+: 150
Females 11-14: 150 15-18: 150 19-24: 150 25-50: 150 51+: 150
Pregnant: 175
Lactating 1st 6 mos.: 200 2nd 6 mos.: 200
Generally the RDA was said to be 150 mcg per day.
There has been no recorded harm done at supplementation doses as high as 20 times the normal amount needed daily. Mega doses of iodine is discouraged as excessive intake can cause enlargement of the thyroid resembling goiter and is actually called iodine goiter.
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