Misinformation about iodine supply endangers health

Statement by the German Society of Endocrinology (DGE) – Hormones and Metabolism

Misinformation on the iodine supply of the German population, as recently shown in a ZDF programme, is misleading and irresponsible, explains the German Society of Endocrinology (DGE). The claim that iodine in animal feed ends up in high quantities ‘on the plate’ and is harmful to health is fuelling ‘iodine fear’, which leads to people avoiding iodine and, in the long term, to an iodine deficiency epidemic, warns the specialist society. Iodine deficiency causes an increased formation of goitres, also known as goitres, and thyroid nodules.

ZDF programme Terra Xpress

In the ZDF programme Terra Xpress on 30 March 2014, it was reported that the population in Germany is at risk from too much iodine in food. According to the programme, certain people also need a diet low in iodine. Another statement: The high prevalence of thyroid disorders in Germany is the result of too much iodine in the diet. The article was framed by an assumption: the iodine deficiency working group, the pharmaceutical industry and the salt-producing industry are behind all of this.

The German Society for Endocrinology (DGE) strongly criticises the tendentious and false reporting, which does not comply with the educational mandate of a public broadcaster. Published data from large German population studies and long-term studies by the Robert Koch Institute on the health of children and adolescents show that the iodine supply in Germany has improved compared to previous years. Both the SHIP study (Study of Health in Pomerania) in northern Germany and the KORA study (Co-operative Health Research in the Augsburg Region) show that the average iodine excretion in adults is around 100 mg/l. This corresponds to the level recommended by the World Health Organisation. This corresponds to the World Health Organisation (WHO) criterion of just sufficient iodine supply in the population. Under no circumstances can it be assumed that there is a risk from excessive iodine intake in Germany. Similar results were obtained in the ‘Study on the Health of Children and Adolescents in Germany’ (KiGGS) for children aged nine to 16 years.

Iodine supply in Germany

Initial, as yet unpublished studies even suggest that the iodine supply of the German population has decreased in recent years. It is therefore more likely that the population is undersupplied rather than oversupplied, according to the DGE.

Iodine deficiency is the most important cause of goitre and thyroid nodules. Around a third of the German population suffer from this condition. All epidemiological studies have shown that eliminating iodine deficiency can reduce the incidence of goitres and nodules in the population. This effect occurs with a delay of decades and is therefore only to be expected in full in Germany in the future.
It is possible to improve the iodine supply with iodised salt and animal feed. Fish consumption as a natural source of iodine is not sufficient in Germany. The iodine supply is regularly monitored, for example by KiGGS and other studies.
There is no thyroid disease or any other disease for which a diet low in iodine is necessary or helpful. This is a widespread misconception that can lead to inappropriate behaviour on the part of patients. Even in the case of an autoimmune thyroid disease, iodised table salt cannot lead to any deterioration.

The increasing prescription of thyroid hormones can be explained by a reduction in TSH reference values. This has led to more frequent ‘laboratory diagnoses’ of hypothyroidism in the last ten years or so, which is accompanied by the early prescription of thyroid hormones. The treatment of only abnormal laboratory values is expressly not favoured by specialists (see also the statements of the specialist societies, for example the American Thyroid Society), as these patients often do not have thyroid disease.

There is no epidemiological evidence to date that cases of autoimmune thyroiditis are increasing in Germany. It is true that unnecessary diagnostics are carried out in Germany and therefore changes without pathological value are often discovered. For example, the presence of low levels of thyroid antibodies is detected, which alone does not mean a diagnosis of autoimmune thyroiditis.

Iodine requirement in certain phases of life

There is a significantly higher iodine requirement in certain phases of life. These include pregnancy and breastfeeding in particular. It is not possible to cover this increased requirement (250-300 mg/day) with the foods commonly consumed in Germany and Europe. For this reason, iodine supplementation is expressly recommended for pregnant women by the specialist societies.

The consequences of an inadequate iodine supply during this period are an increased prevalence of goitre in mother and child and the risk of impairment of the child’s mental development. It is dubious and dangerous to speak of an ‘iodine hazard’ in the context of the consumption of commercially available foods, and even more so to use dubious sources or individual opinions to convey this message. It is also irresponsible to tell patients that their general complaints are caused by iodine intake. Iodine does not cause any complaints and does not lead to strength and health per se in either humans or cattle, but thyroid hormones, of which iodine is an indispensable component, do. Even iodine levels of more than 200 mg/day do not pose a risk. The television programme always mentioned the maximum iodine levels in food. However, even these maximum values only reach the guideline values of 150 mg/day recommended by the World Health Organisation. An ‘iodine excess’, on the other hand, is defined by WHO criteria as a permanent iodine intake of more than 500 mg/day. The German Society for Endocrinology warns against not consuming staple foods as before for fear of supposedly consuming too much iodine. Rather, all efforts must be directed towards ensuring a continuous, sufficient supply of iodine to the population, if necessary also through iodine intake in tablets, for example during pregnancy, in order to prevent long-term negative consequences for health.

Source: German Society for Endocrinology, April 2014: http://www.endokrinologie.net/stellungnahmen_140402.php

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