Why Are Iodide Ions Required In My Diet?

Iodine is a trace element that is essential to human life. Like its chemical relatives, chlorine, fluorine and bromine, elemental iodine is a poisonous gas. However, iodine rarely occurs in its gaseous form.The negatively charged ion of iodine, known as iodide, is found in most biological settings, including your tissue fluids. Iodine's most important function is in the formation of thyroid hormones, which are critical for normal metabolism and growth. The Linus Pauling Institute at Oregon State University reports that iodine deficiency is the most common preventable cause of brain damage in the world.

Hormone Synthesis

According to Elson Haas, author of "Staying Healthy with Nutrition," your body only contains about 15 to 20 mg of iodine. One-fifth of this is concentrated in your thyroid gland, while the rest is in your skin and muscles. Your thyroid -- a bi-lobed gland just below your "Adam's apple" -- captures iodine and incorporates it into two important hormones: triiodothyronine, or T3, and thyroxine, or T4. Since your thyroid gland is relatively small, the iodine concentration in this organ is 1,000 times greater than that in your muscles.

Essential Hormones

Thyroid hormones regulate an astonishing array of processes in your body. Cellular respiration, metabolic rate, growth and development, protein synthesis, nerve and bone formation, reproduction, cholesterol synthesis, skin integrity and mental function are all under the influence of thyroid hormones. Hypothyroidism, the state of thyroid hormone deficiency, affects every tissue in your body. Fatigue, weight gain, poor mental function and decreased resistance to infection are a few of the symptoms associated with hypothyroidism. Iodine deficiency remains a common cause of hypothyroidism worldwide, with the World Health Organization estimating that 2 billion people have insufficient iodine intake.

Sources

Many soils in the world are depleted of their iodine content. Iodine is found in fairly high levels in ocean waters, so ocean fish, shellfish and marine vegetables are good sources of this essential element. Iodized salt contains about 76 mcg of iodine per gram of salt. Since most Americans consume around 3 grams of salt daily, those who use iodized salt are actually exceeding the recommended dietary allowance of 150 mcg for adults. Sea salt also contains iodine, although not nearly as much as iodized salt. Milk can contain iodine if the cows that produce it have iodized salt licks. Depending on how much iodine is in the soil, onions, mushrooms, spinach, green peppers, strawberries, cantaloupe and peanuts may also contain some iodine.

Recommendation

The iodine content of many readily available foods is not easily determined. Consuming more ocean-derived foods is one way to meet your iodine requirements, but many people will continue to depend on iodized salt for their needs. If you are trying to adopt a healthier lifestyle and are avoiding iodized salt, you may need to take a mineral supplement that supplies additional iodine. Recommended dietary allowances for iodine range from 110 mcg for infants to 290 mcg for lactating females. Adequate iodine consumption is particularly important during pregnancy to ensure normal fetal brain and skeletal development.