Role of Iodine Supplements and Iodized Salts During Pregnancy and Nursing

Iodine is an essential micronutrient vital for normal growth and development. When the iodine requirement is not met, growth can be impaired. This micronutrients’ requirement is increased during pregnancy as it is important for prenatal and postnatal growth.

If the requirement is not met, it results in iodine deficiency, which affects the thyroid function of the mother, fetus and the mental development of the child born to iodine -deficient mother. Iodine deficiency causes enlargement of the thyroid gland known as goiter.

Iodine Deficiency Disorder - Causes - NIDDCP Launch - Objectives - NIDDCP Executed - FAQs
To control IDD, the ‘National Goiter Control Program (NGCP)’ was launched which was later renamed as the ‘National Iodine Deficiency Disorder Control Program (NIDDCP)’.

Studies have shown that iodine deficiency during pregnancy results in stunted growth and neuromotor, intellectual, behavioral, and cognitive impairment. Iodine supplementation and iodized salt help prevent iodine deficiency disorders in children.

Iodine deficiency is the cause of preventable brain damage and mental retardation in children. The damage increases with the extent of the iodine deficiency.

Iodine for Prenatal Growth

Iodine plays a crucial role in the fetal development. It is required for the synthesis of thyroid hormone, which is an essential component for normal brain development during fetal and early post-natal life. Iodine also helps to protect babies from certain environmental harms.

The fetal brain development is maximum during the first to second trimester, which is third to the fifth month of pregnancy. During this period neural multiplication, migration and myelinization take place at different sites in the brain, such as the visual and auditory cortex, cerebral cortex and neocortex, hippocampus and cerebellum. This development is dependent on maternal thyroxine sources as the fetal thyroid function is inactive.

Iodine deficiency during pregnancy may lead to lower IQ among kids - Researchers
Mild iodine deficiency during pregnancy could be dimming the intellect of some babies born in the UK, claim researchers.

Studies have shown that correction of iodine deficiency during second trimester reduced neurological disturbances and increased fetal head growth.

Iodine for Expectant Women

Pregnancy increases the demand of thyroid hormones to meet the necessary requirements for normal fetal development. The fetal thyroid is inactive until the 20^th week of pregnancy and therefore is completely dependent on the maternal thyroxine supply. Thus the maternal thyroid produces 1.5 fold more thyroxine. This increases iodine requirement, which is the principle substrate for thyroid hormone synthesis.

During pregnancy iodine deficiency has negative and irreversible effects on the developing fetus.

Critical need of iodine supplements during pregnancy and while nursing
In the U.S. a viewpoint in this week's Journal of the American Medical Association (JAMA) discusses the issue of iodine deficiency in pregnant women.

Most of the women are marginally iodine deficient. Only 15 to 20 percent of pregnant and lactating women are consuming iodine supplements. Most of the vitamin supplements taken during pregnancy do not contain adequate amounts of iodine.

The Indian recommended dietary allowance (RDA) for iodine intake in pregnant and lactating women is 200 mcg a day. Pregnant and lactating women should be advised to take vitamin supplements with adequate iodine.

Iodine in Bread not enough for pregnant women - Study
Iodized salt used in bread is not enough to provide healthy levels of iodine for pregnant women and their unborn children, finds study.

However, there is an upper safety limit for iodine supplementation. Taking more than the recommended dietary intake of iodine increases the risk for thyroid dysfunction in pregnant and lactating women.

Iodine for Postnatal Growth

In neonates, the recommended iodine intake is reflected from the mean intake of iodine in the form of breast milk. However, the iodine content of breast milk is influenced by the dietary intake of the pregnant and lactating women. In postnatal life, thyroid hormones help regulate metabolic processes and maturation of cardiac, pulmonary, bone and central nervous system.

Iodine deficiency during pregnancy has a long-term effect as it affects the subsequent postnatal period as well. Postnatal iodine deficiency is linked to neurological and cognitive function deficits.

Iodine deficiency contributes to reduced school performance, intellectual ability and work performance. According to a study, children born to women with mild-to-moderate iodine deficiency during pregnancy are at increased risk for lower IQ and reading ability by the time they turned 9 years.

Iodine supplements can help prevent the risks associated with iodine deficiency. Studies have shown that iodine supplementation among school children has significantly improved cognitive and motor performance.

Pregnant and lactating women can increase their iodine levels by eating enough dairy products and sea foods. Universal salt iodization is one of the best strategies to prevent neurodevelopment disorders related to iodine deficiency. But most salt consumed by people comes from processed foods, which is prepared with salt that is not iodized. Nowadays, sea salt and kosher salt are most commonly used, which does not contain iodine.

Iodine deficiency is the leading preventable cause of mental impaired function that affects as many as 2 billion people. Prevention of iodine deficiency is possible, provided that the daily iodine requirement to the mother is ensured, before and throughout the pregnancy period as well as during lactating period.

References:

1. http://bmjopen.bmj.com/content/5/4/e007238.abstract

2. http://womensmentalhealth.org/posts/new-recommendations-call-iodine-prenatal-vitamins/

3. http://www.ncbi.nlm.nih.gov/pubmed/23062035

Source-Medindia