Iodine - Prevents Goitre - Information on Deficiency, Benefits, Food Sources
Iodine was one of the first minerals to be recognised as vital for good health. It is still considered one of the most important.
Goitre has been known since prehistoric times. In the Middle Ages, centuries before iodine itself was discovered, physicians in Europe treated goitre with burnt sponge, a substance rich in iodine. This is a remarkable example of the efficacy of folk medidne and the acumen of early physicians.
In practically all countries, there are areas where iodine is lacking in the soil and water. Only one country - Japan - is virtually free from this disease and this is attributed to the relatively high consumption of seaweed as a foodstuff. Seaweed, according to Mc Clendon, a well-known nutritionist, contains about a thousand times as much iodine as any other food. It has been used in the Japanese diet for many generations without any apparent adverse effects.
Iodine was accidentally discovered in burnt seaweed by B. Courtois in 1811, and first isolated by Fyfe in 1819. In 1896, E. Baumann discovered that the thyroid gland, when compared with the other tissues, was very rich in iodine. In 1917, Drs Marine and O. P. Kimball carried out an extensive survey among American school children and conclusively proved the. value of iodine both in preventing and curing simple goitre.
Iodine is greyish-black in colour. When heated, it yields corrosive fumes of a rich violet colour. In the human body, it forms an essential component of thyroxine, the main hormone produced by the thyroid gland. The excessive consumption of certain foods like cabbage, cauliflower, and raddish can cause iodine deficiency. These foods contain a substance which reacts with the iodine present in the food and makes it unsuitable for absorption.
Dietary iodine is absorbed from the gastro-intestinal tract into the blood. The amount of iodine present in the body of an adult is estimated to be about 25 milligrams. Most of it is concentrated in the thyroid gland, where it is stored in the form of thyroglobulin, a complex of protein and iodine. About 30 percent is removed by the thyroid gland for the synthesis of the thyroid hormone, thyroxine, and the rest is excreted by the kidneys. Proteolytic enzymes(those which split up the proteins during digestion) break down this compound, and thyroxine and a small amount of triiodothyronine are excreted into the circulating blood.
What is Goitre??
When the amount of the thyroid hormone in the serum is decreased, the pituitary gland releases a thyroid-stimulating hormone which causes the thyroid gland to produce more cells and to increase in size in an attempt to manufacture more hormones. This results in enlargement of the thyroid gland, which is also called simple goitre.
|Recommended Daily Allowance - Iodine|
Iodine Benefits - Functions in the Body
The chief storehouse of iodine in the body is the thyroid gland. Thyroxine, which is secreted by this gland, contains iodine. This iodine is obtained from the food that is eaten.
Thyroxine, the thyroid hormone, controls the basic metabolism and oxygen consumption of tissues. It controls the utilisation of sugars. It regulates the rate of energy production and body weight and promotes proper growth. It increases the heart rate as well as urinary calcium excretion. It improves mental alacrity and promotes healthy hair, nails, skin, and teeth.
Small doses of iodine are of great value in the prevention of goitre in areas where it is endemic, and are of value in treatment in the early stages. Larger doses have a temporary value in patients with hyperthyroidism who are being prepared for surgical operation.
Iodine Rich Food Sources
The best dietary source of iodine is iodised salt. Sea foods and spinach also contain reasonable quantities of iodine.
Iodine Deficiency Symptoms
Cretinism occurs in children whose diet lacks iodine. A cretin is a dwarfed child who is mentally retarded, has an enlarged thyroid gland and defective speech, and a gait that is clumsy. His skin is rough, and hair, sparse. Such a child usually has brittle nails, bad Iteeth, and is prone to anaemia.
Among adults, myxoedema can result from an iodine deficiency, affecting the adequate production of the thyroid hormone. The symptoms of this disease are a slower rate of metabolism, thickening of the skin, loss of hair, and general physical and mental sluggishness. Such persons also have enlarged thyroid glands.
A dietary lack of iodine may lead to anaemia, fatigue, lethargy, loss of interest in sex, a slow pulse, low blood pressure, and a tendency towards obesity. A serious deficiency may result in high blood cholesterol and heart disease.
Iodine is so important to life that a mere three and a half grains of this precious element stands between intelligence and idiocy! The thyroid gland can manufacture the hormone thyroxin only from organic iodine taken through the mouth.
Iodine Side Effects - Precautions
There are no known toxic effects from natural iodine. However, iodine as a drug can be harmful if prescribed incorrectly.