Iodine is a naturally occurring element that is counted among the trace elements and is a vital nutrient for humans. It is absorbed through our food and is essential for the formation of the thyroid hormones T3 (triiodothyronine) and T4 (tetraiodothyronine). These hormones are involved in the control of growth, bone formation, energy metabolism and brain development.
Iodine occurrence in soil and water can be subject to strong fluctuations. As a result, the contents in animal and plant foods also vary greatly. Iodine-rich food sources include marine fish and seafood, seaweed and mineral waters. Provided that iodine-enriched feed is used for livestock, meat, eggs, milk and dairy products also provide appreciable amounts of iodine. Vegetable foods contain lower iodine levels.
Dietary iodine deficiency leads to an insufficient concentration of thyroid hormones in the blood and consequently to a growth in the size of the thyroid gland (goiter formation) in order to compensate for the deficiency by increased production of thyroid hormones. A pronounced iodine deficiency can lead to hypothyroidism, which causes a number of complaints and negative effects on the organism.
Excessive iodine intake can also lead to impaired thyroid function. Causes often include the use of iodine-containing contrast media and iodine-containing medications or excessive consumption of iodine-rich dietary supplements and seaweed. Infants, pregnant women, and the elderly, as well as individuals with thyroid disease, are particularly susceptible. However, overdoses are hardly to be feared via the normal diet and iodized table salt.
Situation in Austria
In recent years, seaweed and algae products have increasingly been offered on the European market. These products are characterized above all by a very variable and often high iodine content. In most cases, there is no information about preparation and recommended consumption, which can lead to the intake of very high amounts of iodine.
Since Austria was considered an iodine deficient area with an increased incidence of goiter, this can have adverse health effects for people with thyroid diseases, but also for thyroid-healthy individuals.
There are currently no EU maximum levels or national regulations for iodine in seaweed and seaweed products. In 2018, the European Commission published Recommendation (EU) 2018/464 on the monitoring of metal and iodine concentrations, according to which Member States should examine and monitor seaweed, algae and products thereof for their iodine content. In Austria, this recommendation is implemented within the framework of official control. The samples are examined and assessed by us. Labelling deficiencies were found in the products objected to, including missing warnings regarding iodine content and incorrect or missing consumption quantities. Other products were found to be harmful to health due to their very high iodine content.
As an upper limit for a tolerable daily iodine intake, the European Food Safety Authority (EFSA) set 600 µg iodine/day for adults and 200 µg iodine/day for children aged 1 to 3 years. Since iodine deficiency prevailed in Austria for many decades, older people in particular have developed autonomous centers in the thyroid gland. An excess of iodine can activate these autonomous centers and cause hyperthyroidism. For precautionary reasons, the ÖGE recommends an iodine intake via food of 500 µg iodine/day not to be exceeded in adults.
Without concrete information on the quantitative use of the algae, their preparation and the amount of consumption of these products, very high amounts of iodine can be absorbed, which are far above the tolerable daily intake. Therefore, the consumption of these products may harm the health of consumers. The population groups of young children, pregnant women and elderly people are particularly sensitive.
Last updated: 10.10.2023