One of the essential trace elements for our body
Iodine is a trace element, i.e. a metallic substance that is found in very small quantities in our body and is absolutely essential for its proper functioning. Iodine also exists in its natural state mainly in the oceans, from where it evaporates, passes into the atmosphere and then falls back to earth with rainwater. In our body it is only through food that it is brought in. Its absence can be seriously harmful to the body.
Its usefulness
In our body, iodine is part of the thyroid hormones that are essential for the growth of all our tissues, especially those of the brain.
The thyroid is a small gland located at the base of the neck that produces two hormones that we call in simple language T3 and T4 depending on their iodine content. So, if the thyroid is not supplied with iodine, it cannot make its hormones!
For the baby, it's the same thing! From the fetal stage on, his thyroid needs iodine to ensure the development of his brain. However, during the first months of its life, the fetus is unable to make its own hormones. It is the mother who provides it with them and for that she needs iodine!
And even then, when its thyroid starts to function, around the middle of pregnancy, it still needs iodine to synthesize its own hormones and the only solution is for its mother to provide it through the placenta. The fetus is totally dependent on the mother's iodine for its brain development.
Pregnancy = increased need for iodine
Pregnancy is a real period of hard labour for the thyroid:
First the need for iodine is increased: certain hormones produced in abundance during pregnancy, in particular oestrogen and beta hCG, (the hormone detected by pregnancy test strips), force the thyroid to work intensely. It therefore needs more iodine.
Pregnancy also increases iodine loss: pregnancy increases the elimination of iodine in the urine. Finally, the mother's iodine passes through the placenta to nourish the foetus.
All these factors contribute to the increased workload of the thyroid gland, which requires more iodine to produce its hormones, T3 and T4.
What if I run out of iodine during my pregnancy?
The "forced" work of the thyroid to compensate for its lack of iodine can result in a goiter (a lump at the base of the neck): in ancient times, when many women were chronically deficient due to poor nutrition, pregnancy was diagnosed by the increase in the diameter of the neck ...
The size of the goitre is proportional to the intensity of the initial deficiency and its duration. If the lack of iodine is compensated for quickly, the goitre is reabsorbed and disappears. On the other hand, if at each pregnancy a woman was in lack of iodine, the goiter would end up persisting and the patient would be in a state of hypothyroidism. This results in symptoms such as fatigue, nervousness, sleep disturbances, increased blood pressure, and increased risk of miscarriage. In addition to what may happen to the mother, the consequences may be more serious for the unborn baby, especially on the intellectual level.
What about my baby?
If the mother lacks iodine, the foetus will lack iodine ...
The fetal brain is the organ most sensitive to iodine deficiency. It is the fetal brain that during intrauterine life and the neonatal period needs a lot of thyroid hormones to develop due to its very rapid growth. The extreme stage of iodine deficiency, as can still be observed in some very poor populations around the world, is called "goitreous cretinism", a form of profound mental debility. But, if this was still observed in some remote regions of France at the end of the 19′ century, today it has completely disappeared from our country.
Do I get enough iodine?
Only the level of iodine in the urine, ioduria, would make it possible to know whether or not one is in need of iodine. This examination can be carried out by a laboratory, but it is not covered by social security ... and for this reason is never carried out. In fact, as you cannot know your "iodine status" and the major risk is at the time of pregnancy, it is better to do everything possible to avoid being in deficit and to increase your intake!
In which foods can iodine be found?
Iodine is mainly provided by foods of marine origin: algae (20 to 50 mg/100g), fish: (25 to 75 µg/100g), crustaceans and molluscs (40 to 320 µg/100g).
Eggs and dairy products are a significant source.
Meat, fruit and vegetables, and drinking water are very poor.
You should also be aware that some texturing agents such as alginates and carrageenates or colouring agents used in industrial food are rich in iodine.
In France, the iodization of table salts has been authorized since 1952, at a rate of 15 mg/kg, and today infant milks are also supplemented with iodine. In spite of this, France is still in a state of slight deficiency.
Beware of the risk of overdosing in IODE by excessive consumption of algae!
In Germany, the Federal Institute for Consumer Health Protection and Veterinary Medicine (Bundesinstitut für gesundheitlichen Vebraucherschutz und Veterinärmedizin) points out that the consumption of dried algae could present risks. Dried seaweed may contain up to 6500 mg of iodine per kg. Up to 20 mg of iodine is safe for health, but higher doses can lead to hyperthyroidism (irritability, weight loss, insomnia, etc.) and skin damage.
Daily iodine requirements?
Outside pregnancy, the recommended intakes are 100 to 150 µg/day. In pregnant women and during breastfeeding, these requirements are increased to 200 µg/day. On average, however, food provides 70 to 80 µg/day of iodine. For this reason, during pregnancy, even a diet rich in iodine, even if you live by the sea, cannot do everything ...
In Europe, the risk of iodine deficiency is moderate. In our country, the results of the SU.VI.MAX. (*) carried out on more than 7,000 women revealed a slight iodine deficiency, characterised by a mean ioduria of 82 µg/l. According to the World Health Organisation, a deficiency is said to be slight if urinary iodine levels are between 50 and 100 µg/l, moderate between 25 and 50 µg/l and severe below 25 µg/l. However, according to experts, iodine deficiency is the most easily preventable cause of intellectual retardation in children. This is why, after having recommended the iodisation of cooking salts and infant formula, in view of the potential risk of deficiency which remains despite these measures, most scientists now recommend iodine supplementation for pregnant women.
(*) VALEIX p et al 'Iodine deficiency in France. Lancet 1999; 353′ 1766-1767
Studies have shown that it is possible to compensate for iodine deficiency during pregnancy by supplementation. This is effective in preventing neonatal hypothyroidism and improving children's intellectual performance. For example, it has been observed that children born to supplemented mothers had higher IQs than those born to mothers whose deficiency had not been corrected, provided that supplementation is started early in pregnancy, when the fetus needs it most. It is advisable to continue iodine supplementation, including during breastfeeding, i.e. as long as the child is developing. It is even possible to start before pregnancy to strengthen the iodine capital. Moreover, it has been proven that this supplementation, carried out at moderate doses (50 to 200 µg per day) is not dangerous, neither for the mother nor for the child.
In all cases: ask your gynaecologist for advice, only he or she will be able to assess your needs and give you the appropriate supplementation.
The global elimination of iodine deficiency is within our reach (source WHO).
21 DECEMBER 2004 | GENEVA - The number of countries where iodine deficiency is a public health problem has halved in ten years, according to a new global report by the World Health Organization (WHO) on the status of iodine. Iodine deficiency is an important cause of disorders in the mental development of children. The main strategy, universal salt iodization, has been successful. However, iodine deficiency is still found in 54 countries and sustained efforts will be needed to expand salt iodization programmes, as indicated in the report Iodine status worldwide.
Iodine deficiency is a major threat to the health and development of people around the world, especially pre-school children and pregnant women," says Dr LEE Jong-Wook, Director-General of WHO. This report shows that global elimination of this problem is within our reach. »
The deficiency is the result of poor soil iodine availability, leading to low iodine concentration in food products and thus insufficient intakes for the population. When standards are not met, the thyroid may no longer be able to synthesize thyroid hormone in sufficient quantities. The resulting low blood concentration is the main cause of a number of metabolic and developmental abnormalities, known as iodine deficiency disorders.
Cretinism is the most extreme manifestation, but current efforts to eliminate iodine deficiency are motivated primarily by the more attenuated neurological and mental disorders responsible for poor academic performance, diminished intellectual capacity and impaired fitness for work.
WHO recommends universal salt iodization, i.e. the use of iodized salt in food and feed to prevent or combat iodine deficiency. Under the leadership of UNICEF and WHO, most countries with this public health problem have implemented this strategy. UNICEF estimates that 66 per cent of households worldwide now have access to iodized salt.
The new WHO report provides an estimate of the status of iodine in the world's population and reports on the progress made by each country over the past decade towards eliminating iodine deficiency. It is based on the WHO iodine deficiency database, which compiles data on urinary iodine concentration, prevalence of goitre (enlarged thyroid gland) and monitors the extent, severity and distribution of iodine deficiency worldwide. UNICEF funds the operation of this database.
The number of countries where iodine deficiency remains a public health problem was 54 in 2003, up from 110 in 1993, which, as WHO says, demonstrates the effectiveness of the universal salt iodization strategy. Iodine intakes are now adequate in 43 of the 126 countries for which figures were available in 2003. Of the 54 countries with iodine deficiency, 40 have low levels of iodine deficiency and 14 have moderate to high levels of iodine deficiency. Salt iodization programmes need to be strengthened in these countries.
In 29 countries, iodine intakes are slightly too high, and in some cases excessive. Daily iodine intakes above the safe limit can lead to thyroid dysfunction in sensitive individuals. This underlines the importance of strengthening quality control of iodized salt to ensure that it is at concentrations sufficient to cover optimal dietary intake without reaching excessive levels. WHO also stresses the need to ensure that the promotion of iodized salt does not lead to over-consumption of salt that may contribute to the development of high blood pressure: salt can be iodized to a level compatible with the WHO recommended intake of up to 5 g per day.