Iodine Deficiency Disorder
د هديل فاضل فرهود
*Iodine is an essential
constituent of the thyroid hormones. The major role of Iodine in nutrition arises from the importance of thyroid hormones to stimulate cell oxidation and play a major role in regulating the basal metabolic rate of the adult ,And the growth and development of children .
*The total amount of iodine in the body of an average adult 20-50mg distributed as Follows :- Muscle 10%,skin 10%,skeletal structure 7%,thyroid 65% , and the remaining is scattered in other endocrine organs and the central nervous system.
*The concentration of iodine in the thyroid gland is more than 100times that in the muscle and 10.000 times that in the blood.
*Iodine deficiency is the world s most significant cause of preventable brain damage and mental retardation. The effect of iodine deficiency on a country s population has a negative impact on the entire economy of affected nations. Globally, 2.2 billion people (38% of world s population) live in area with Iodine deficiency & risks of its complications. (20-30 % sign). Needed of iodine are higher:
During growth of infant, children and adolescents &during pregnancy and lactation.Food sources:-vegetable Products are low in iodine
(because the iodine content of a
given plant food depends on the type of soil and soil usually contain little of this element).
Sea water contains iodine, sea food which is the only rich source of iodine.
Fresh water fish: 20 – 40 Mg/Kg Iodine
Salt water fish: 300 – 3000 Mg/Kg Iodine
The amount of iodine in dairy products, meat, and egg is generally good, but depend on the composition of animal feed.
Iodine is readily absorbed, and excess intake Iodine requirement
- Infant 1st 12 months of age ……………. 50 microgram
- Children 2-6 years of age ……………….90 microgram
- School age children ……………………...120 microgram
- Adults more than 12 years ………………150 microgram
- Pregnant & Lactating ……………………200 microgram
Minimum amount of iodine required to replace the turnover of thyroid hormones is 50 microgram/day. iodine deficiency occurs when iodine intake fall below the recommended levels The usual recommended level for the population mean intake of iodine is 100-150 Mg/day ,This level is adequate to maintain the normal thyroid function that is essential for normal growth and development . In the presence of goitrogens in the diet, the intake should be increased to 200-300 Mg/day
is controlled by renal excretion Absorption is usualFunction of iodinely complete but may be delayed in Protein –energy malnutrition.
1-It is an integral part of thyroid hormones that play a major role in regulating growth and development, also have important role in regulation of metabolic rate.
2-It is required for early development of nervous system during fetal life
3-It is needed for normal reproductive function
Causes of IDD:1- Lack of iodine in the diet. Because iodine can not be stored for long times in the body, tiny amount must be consumed regularly, but food grown in iodine poor soil will not provide sufficient dietary iodine.
2-Increased requirement: Developing fetus, newborn, young child, adolescents especially in females, pregnant and lactating women
3-Intake of goitrogens: substances occur naturally in food, that acts by blocking absorption, utilization of iodine.
4-Deficiency of enzymes need in the metabolism of iodine.
The spectrum of iodine deficiency disorder:Fetus
Abortion and still birth, congenital anomalies, increased perinatal mortality
Increased infant mortality &psychomotor defects.
Neonate:-
Neonatal goiter, Neonatal hypothyroidism &increased susceptibility to nuclear radiation.
Child and adolescent -
Goiter &Juvenile hypothyroidism, Impaired mental function, Retarded physical development
Adult
Goiter with its complications, hypothyroidism, impaired mental function.
Iodine-induced hyperthyroidism
Society
Lower productivity and higher demand on social services.
GoiterDeficiency of iodine
in diet causes the thyroid gland to enlarge due to its desperate effort to product the hormones; this enlargement is known as goiter.
The damage done by this lack of thyroid hormone varies in severity depending on the time of life at which the deficiency occurs
. Goiters vary in size from those that you can only fell to those that you can easily see .Goiter often start in childhood and gradually enlarge, particularly during puberty.
A goiter often gets bigger during pregnancy and lactation because the body needs more thyroid hormone at that time, it may continue to increase in size with each new pregnancy .
.