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BgVV warns against health risks from iodine-containing algae products

13/2001, 03.04.2001

Institute recommends the laying down of maximum levels on the EU level and labelling

Around the world every year more than nine million tonnes of marine macro algae are harvested. The main producer countries are China, Japan, the Philippines and North and South Korea. The macro algae, which are mainly cultivated in aqua cultures, include brown, red and green algae. Whereas algae products have been a fixture in traditional cuisine in Asian countries for centuries where they are cooked as vegetables, used in salads or sold as spices, they have only taken on importance in the last few years on the German market. A problem could result from the, in some cases, extremely high iodine content of the macro algae which is only rarely stated on the products. The iodine content in dried algae and kelp products may be particularly high. Food control by the federal Länder found in algae products, which were the subject matter of complaints, up to around 6,500 mg iodine per kilogram dry weight. In the opinion of BgVV foods and spices made of algae or kelp with more than 20 mg per kg dry weight may damage health.

In regions with a sufficient iodine supply, like for instance Asia, where the macro algae are traditionally used, a sudden over-supply of iodine is unlikely to be linked with a health risk. The situation is different in so-called endemic iodine deficiency regions which include Germany. As a consequence of the lack of adaptation to chronic iodine deficiency in the thyroid gland, frequently small autonomous centres (autonomous adenomas) form above all in older people. If these autonomous centres are activated through a sudden excess of iodine, this can lead to a life-threatening hyperfunction of the thyroid gland. On the other hand, an excess of iodine in the case of normal thyroid gland function can inhibit the synthesis of thyroid gland hormones which could lead to a compensatory hypofunction and the formation of a goitre. Patients with Dermatitis herpetiformis Duhring - a rare inflammatory skin disease - are also at risk. Their symptoms may be exacerbated as a consequence of the excess iodine.

The Deutsche Gesellschaft für Ernährung e.V. (German Society for Nutrition) recommends a total daily iodine intake of 180-200 microgram (µg) for young people and adults. The World Health Organisation (WHO) gives 1,000 µg per day as the upper tolerable intake level. Consequently, in the iodine deficiency region Germany, an intake of 500 µg iodine per day should not be exceeded for precautionary reasons. For food supplements BgVV has, therefore, recommended an upper limit for iodine of 100 µg per day and the maximum levels were also laid down for the use of iodised table salt in formulations. For the same reason BgVV believes that algae products with more than 20 mg iodine/kg dry weight are not marketable for reasons of consumer health protection. It advocates the laying down of maximum levels in Europe and the compulsory labelling of iodine content.

An extensive opinion of BgVV on the marketability of algae products with a high iodine content can be found on the Website (www.bgvv.de) under the keyword "Foods".

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