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Iodine is vital for good thyroid function, which in turn is essential for good health. Iodine deficiency was prevalent in the U.S. before the iodization of salt became a common practice in the 1920s [Journal of the American Dietetics Association 79 (1981): p.17].
Causes & Development
Some otherwise healthful foods contain goitrogens - substances which can interfere with iodine uptake or hormone release from the thyroid gland. These foods are generally only a concern if iodine intake is low. Consumption of brassicas, such as cabbage, Brussels sprouts, broccoli and cauliflower, increase the requirements for iodine, especially if consumed raw. Soybeans, raw flaxseed, cassava (used in tapioca), sweet potatoes, lima beans, maize and millet also increase the requirements for iodine.
Some individuals deliberately take kelp to try to lose weight by over stimulating the thyroid. This is a dangerous practice.
Diagnosis & Tests
An iodine intake of less than 20mcg per day is considered severe deficiency; 20-50mcg per day is considered moderate deficiency and 50-100mcg per day is considered mild deficiency.
Treatment & Prevention
In the US, iodised salt is widely used and some other foods are fortified with iodine. In Canada all table salt is iodised. The UK has no iodine fortification strategy for plant foods or salt.
Complications
Iodine deficiency during pregnancy and early infancy can result in cretinism (irreversible mental retardation and severe motor impairments).
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Signs, symptoms & indicators of Iodine Requirement:
Conditions that suggest Iodine Requirement: | | | | | Hormones |  Hypothyroidism
 Hyperthyroidism | Hyperthyroidism may occur, particularly in elderly people, due to long term slight iodine deficiency as this may result in additional nodules on the thyroid. |
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Tumors, Malignant |
Ovarian Cancer| | Geographic differences in the rates of breast, endometrial and ovarian cancer appear to be linked to iodine intake, suggesting that low intake may produce increased gonadotrophin stimulation leading to a hyperestrogenic state characterized by a relatively low estriol : (estrone + estradiol) ratio which may increase the risk of these cancers. [Lancet, pp.890-1, 1976] |
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Risk factors for Iodine Requirement: | | | | | Supplements and Medications | Some/no iodine supplementation
Counter-indicators:
 Much iodine supplementation |
Symptoms - Food - Intake |
Low iodine consumption
Counter-indicators:
 (High) dairy product consumption| | Consumers of dairy products generally receive sufficient iodine due to the use of iodine-containing disinfectants for cleaning dairy equipment, which leach into the milk. |
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Symptoms - Food - Preferences |
 Vegetarian/vegan/raw food diet| | Iodine is typically undesirably low (about 50mcg per day compared to a recommended level of about 150mcg) in vegan diets unless supplements, iodine-rich seaweeds or foods containing such seaweeds are consumed. The low iodine levels in many plant foods reflect the low iodine levels in the soil. About half the iodine consumption of omnivores comes from dairy products.
In October of 2003, one of many articles appeared on iodine deficiency in vegetarians and vegans [Annals of Nutrition and Metabolism 47 (2003): p.183]. Quoting from the paper: "One fourth of the vegetarians and 80% of the vegans suffer from iodine deficiency..." Only 9% of the meat-eaters were deficient. The milk drinkers were protected in part because iodine-containing disinfectants are used to clean the milk processing equipment. None of the vegetarians and vegans were eating sea vegetables, and none were using iodized salt - they were all using "natural" sea salt, which has significantly less iodine. |
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Iodine Requirement suggests the following may be present:
Iodine Requirement can lead to:
Recommendations and treatments for Iodine Requirement: | | | | | Botanical |  Bladderwrack| | The amount of iodine in bladderwrack is highly variable, probably as a result of different amounts of iodine in the water where it grows. A reasonable portion of bladderwrack may contain the U.S. adult recommended dietary allowance (RDA) of iodine (150mcg). |
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Mineral |
 Iodine |
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KEY | | Weak or unproven link | | | Strong or generally accepted link | | | Proven definite or direct link | | | Strongly counter-indicative | | | Very strongly or absolutely counter-indicative | | | May do some good | | | Highly recommended |
GLOSSARY
Cancer
Refers to the various types of malignant neoplasms that contain cells growing out of control and invading adjacent tissues, which may metastasize to distant tissues.
Hormones (Hormone)
Chemical substances secreted by a variety of body organs that are carried by the bloodstream and usually influence cells some distance from the source of production. Hormones signal certain enzymes to perform their functions and, in this way, regulate such body functions as blood sugar levels, insulin levels, the menstrual cycle, and growth. These can be prescription, over-the-counter, synthetic or natural agents. Examples include adrenal hormones such as corticosteroids and aldosterone; glucagon, growth hormone, insulin, testosterone, estrogens, progestins, progesterone, DHEA, melatonin, and thyroid hormones such as thyroxine and calcitonin.
Hyperthyroidism (Hyperthyroid)
An abnormal condition of the thyroid gland resulting in excessive secretion of thyroid hormones characterized by an increased metabolism and weight loss.
Hypothyroidism (Hypothyroid)
Diminished production of thyroid hormone, leading to low metabolic rate, tendency to gain weight, and sleepiness.
Iodine
A essential mineral that is an integral part of the thyroid hormones, thyroxin and triiodothyronine which have important metabolic roles and govern basal metabolism. The best known iodine deficiency symptom is goiter. Other iodine deficiency problems are reduced vitality, hypothyroidism, inability to think clearly, low resistance to infection, loss of control of the muscles of the mouth resulting in mouth contortion and drooling, defective teeth, tendency to obesity and cretinism which is a congenital abnormal condition marked by physical stunting and mental deficiency.
Metabolism (Metabolic, Metabolize, Metabolizes, Metabolizing)
The chemical processes of living cells in which energy is produced in order to replace and repair tissues and maintain a healthy body. Responsible for the production of energy, biosynthesis of important substances, and degradation of various compounds. Also defined as the sum total of changes in an organism in order to achieve a balance (homeostasis): Catabolic burns up, anabolic stores and builds up; the sum of their work is metabolism.
Microgram (mcg, Micrograms, ug)
0.000001 or a millionth of a gram.
RDA (RDAs, US RDA, USRDA)
Recommended Daily Allowance of vitamins or other nutrients as determined by the FDA. U.S. RDAs are more widely used than RDAs, and focus on 3 age groups: Infants of 0-12 months; Children of 1-4 years; Adults and children of more than 4 years.
Thyroid (Thyroid Gland)
The thyroid gland is an organ with many veins, anchored around the front of the throat near the voice box. It is essential to normal body growth in infancy and childhood. It absorbs iodine from the diet and releases thyroid hormones - iodine-containing compounds that help govern the rate of the body's metabolism (its total life processes), affecting body temperature, and regulating protein, fat and carbohydrate catabolism in all cells. They keep up growth hormone release, skeletal maturation, and heart rate, force, and output. They promote central nervous system growth, stimulate the making of many enzymes, and are necessary for muscle tone and vigor. To a high degree, metabolism is regulated by the hormone thyroxine, which can be made by the thyroid if enough organic iodine is available. An enlarged thyroid gland that is not cancer is sometimes called goitre.
Vegan (Veganism, Vegans)
A person who consumes no animal products of any kind. In other words, vegans do not consume meat, fish, fowl, dairy products, eggs, honey, or products containing gelatin or any other animal-derived ingredients such as whey powder or food colorings.
Vegetarian (Lacto-Ovo-Vegetarian, Vegetarianism, Vegetarians)
A person who consumes no meat, fish or fowl (chicken, turkey, etc.), but who may consume animal products such as dairy products (milk, cheese, butter, etc.), eggs or honey.
Zinc
An essential trace mineral. The functions of zinc are enzymatic. There are over 70 metalloenzymes known to require zinc for their functions. The main biochemicals in which zinc has been found to be necessary include: enzymes and enzymatic function, protein synthesis and carbohydrate metabolism. Zinc is a constituent of insulin and male reproductive fluid. Zinc is necessary for the proper metabolism of alcohol, to get rid of the lactic acid that builds up in working muscles and to transfer it to the lungs. Zinc is involved in the health of the immune system, assists vitamin A utilization and is involved in the formation of bone and teeth.
Last updated: Jun 10, 2009
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