Can Too Much Iodine be Harmful?

Last updated on July 26th, 2022 at 05:05 pm

Do you know recent news in Nepal shows that Nepalese consume a higher quantity of iodine in their diet?

They also have indicated that the Ministry of Nepal is launching a nationwide campaign to lessen the daily intake of salt.

Consuming an excessive amount of salt leads to several non-communicable diseases like hypertension, cardiovascular disease, and hyperthyroidism.

In 1993, Nepal started fortification of salt to address the issue of visible goiter, caused by lack of iodine in the diet. Visible goiter went down from 55% in 1965 to 0.4% in 2007, which is one of the public health achievements in Nepal.

However, solving one problem might have created another. A micronutrient survey conducted in 2016 showed that 67.5% of households in Nepal have excessive iodine intake in food.

WHO guidelines are followed in Nepal to maintain minimum iodine content in salt.

According to the Nepal Food Act, the amount of iodine in salt in packaging should be at least 50 ppm and at the retail store should be at least 30 ppm.

A recent study shows that the mean iodine concentration of 54.7 ± 16.2 mg/kg in household salt, which corresponds to the mean daily iodine intake of Nepali households was 547 µg. This is 3.6-fold higher than the WHO-recommended value of 150 µg for adults.

This corresponds to the increase in the prevalence of thyroid disorders in the last 10-15 years in Nepal. Thus, it is high time that we learn about the importance and usage of this micronutrient.

What is Iodine?

Iodine is an element used by thyroid glands. Iodine cannot be produced in the body by humans, so it must be consumed through the diet.

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The ocean is the major source of natural iodine. The natural source of dietary iodine is seafood and seaweed. However, as these foods are not the main constituents of most diets, the largest source of iodine in most diets are vegetables, meat products, eggs, and dairy products.

It is also added to the table salt to ensure an adequate intake of iodine.

Why do We Need to Consume Iodine?

Iodine is an essential dietary element for human beings, as it plays a significant biological role in the synthesis and function of thyroid hormones such as T4 and T3.

Via thyroid hormones, iodine plays an important role in the expression of genes, growth, and development, and to maintain proper neurological and cognitive functions.

What Happens if There is Not Enough Iodine in the Body?

People who do not get enough iodine cannot make a sufficient amount of thyroid hormone in the body.

In pregnant women, severe iodine deficiency causes intellectual disability, stunted growth, and delayed sexual development in the fetus. It also decreases the overall cognitive function of the child and can result in congenital abnormalities, spontaneous abortion, and stillbirth.

Further, iron deficiency can cause lower IQ in children and reduces the ability to think clearly and properly in adults.

The physical outcome of lower iodine level in a goiter. Goiter is an abnormal enlargement of the thyroid gland that causes difficulty breathing, hoarseness, and swallowing.

How Much Iodine Should I Eat in a Day?

The daily recommended value of iodine per day is 150 mcg for children over 4 years to adults.

However, Iodine also has upper limits (i.e., the maximum amount you should consume in a day).

The daily upper limits of the iodine that has to be consumed include intake from all resources i.e., food, beverage, and supplements.

Life stage	Upper limit (in mcg, micrograms)
Birth to 12 months	Not established
Children 1-3 years	200 mcg
Children 4-8 years	300 mcg
Children 9-13 years	600 mcg
Teens 14-18 years	900 mcg
Adults	1,100 mcg