Iodine Deficiency Symptoms - Impact on Babies and IQ of children

Iodine is an essential nutrient element that is critically required for the body to produce the thyroid hormone. Iodine deficiency can lead to the enlargement of the thyroid gland and to mental retardation in children whose mothers consumed inadequate iodine during pregnancy.

Prior to 1930 iodine deficiency was common in certain parts of Canada, USA, Britain and other countries. The addition of iodine to common salt has improved the situated in developed countries.

There is also greater awareness of the problem and how to prevent iodine deficiency symptoms by eating food that naturally contain iodine, such as dairy products, seafood and soy products.

However the problem remains in less developed countries and about 40% of the world's population remains at risk for iodine deficiency.

Despite the progress that has been made, women in the UK have been warned recently, that even mild iodine deficiency during pregnancy could be reducing the intellectual capacity of their babies.

Recent research, that included 1,000 families, found a correlation between lower IQ's and reading score for primary school children whose mother had insufficient iodine while pregnant. 

About two thirds of the women tested had iodine deficiencies during their pregnancies.

This article discusses this research and highlights the recommended amount of iodine required every day and the best natural dietary sources of iodine.

The researchers have advised women of child-bearing age to check and make sure that they maintain adequate iodine levels in their diets by eating dairy products, soy products, fish and other natural sources of iodine.

Location of the Thyroid, which can become enlarged and cause swellings in this area of the neck due to Iodine deficiencies
Location of the Thyroid, which can become enlarged and cause swellings in this area of the neck due to Iodine deficiencies. Source: Public Domain

Iodine Needs, Deficiencies and How Deficiencies are Diagnosed

The best way to determine whether you have any iodine deficiency is to have a urine test.

Iodine deficiency is defined as a urinary iodine concentration less than 50 micro g/l. This requires a daily intake of 150 micro g /day.

The recommended intake of Iodine for various ages and genders are:

1 - 8 years boys and girls # 90 micro g/day

9 - 13 years boys and girls #120 micro g/day

14-18 years boys and girls # 150 micro g/day

19 - 70 years men # 150 micro g/day

19- 70 years women # 150 micro g/day

Women During Pregnancy # 220 micro g/day

Women During Lactation # 270 micro g/day

The table below summarizes the various levels of iodine decificincy and how it relates to levels of iodine in the urine and associated dietary intakes of iodine.

Foods Rich in Dietary Iodine

(see Details in table Below)

Dairy Products

Eggs

Supplements

Seafood

Soy Products

Research on Iodine Deficiencies in Pregnant Women in UK

A study of 1,000 families has shown that mild iodine deficiency is still relatively common affecting two-thirds of the women in the study.

Children of women with an iodine-to-creatinine ratio of less than 150 micro g/g (urine Iodine concentrations less than about 100 micro g/l) had:

Lower IQs at the age of eight

Worse reading ability aged nine.

The study suggested that iodine deficiencies during pregnancy may produce risks that a child may not reach their full potential.

The British Dietetic Association recommends that pregnant and breastfeeding women need a minimum of 250 micrograms of Iodine per day and other adults need at least 150 micrograms of Iodine per day.

What Levels of Iodine Intake Causes Known Deficiencies?

The table below summarizes the Iodine levels in the urine, equivalent intake levels from food and the associated level of deficiency.

Iodine Intake Requirements and Deficiency Status

Median Iodine Level in the Urine
Iodine Intake to Maintain Urine Level Specified
Iodine Deficiency Status
Recommended Level in Urine - greater than 100 micro g/l
Recommended Dietary Allowance for iodine in adult men and women is 150 micro g per day
 
less than 20 micro g/l
less than 30 micro g/ day
Severe deficiency
20-49 micro g/l
30-74 micro g/ day
Moderate deficiency
50-99 micro g/l
75-149 micro g/ day
Mild deficiency
100-199 micro g/l
150-299 micro g/ day
Optimal
200-299 micro g/l
300-449 micro g/ day
More than adequate
more than 299 micro g/l
more than 449 micro g/ day
Possibly Excessive with Overdose Symptoms

Iodine Levels in Common Foods per Typical Serving or 100g

Food
Serving Size
Average iodine content per serving (micro g)
Oysters
100g
160
White fish
100g
115
Sushi (containing seaweed)
100g
92
Shellfish
100g
90
Yoghurt
150g
75
Cow's milk
200ml
65
Tinned salmon
100g
60
Oily fish
100g
50
Bread (made with iodised salt)
100g
46
Organic cow's milk
200ml
45
Steamed snapper
100g
40
Cheddar cheese
100g
23
Eggs
100g
22
Ice cream
100g
21
Eggs
1 egg (50g)
20
Chocolate milk
100g
20
Flavoured Yoghurt
100g
16
Cheese
40g
15
Regular milk
100g
13
Meat
100g
10
Poultry
100g
10
Canned tuna
100g
10
Nuts
25g
5
Bread
1 slice (36g)
5
Fruit and veg
1 portion (80g)
3
Bread (without iodised salt)
100g
3
Beef, pork, lamb
100g
1
Apples, oranges, grapes, bananas
100g
1

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How iodine in the blood is used by the body to synthesise the thyroid hormone
How iodine in the blood is used by the body to synthesise the thyroid hormone. Source: Public Domain
Countries with major problems cause by Iodine Deficiencies
Countries with major problems cause by Iodine Deficiencies. Source: Public Domain
Essential Functions of iodine
Essential Functions of iodine. Source: Public Domain
Iodine Rich Foods
Iodine Rich Foods. Source: Public Domain