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Thyroid dysfunction following a kelp-containing marketed diet
  1. Tiziana Di Matola1,
  2. Pio Zeppa2,
  3. Maurizio Gasperi3,
  4. Mario Vitale2
  1. 1A.O.R.N. dei Colli Hospital, Naples, Italy
  2. 2University of Salerno, Baronissi, Salerno, Italy
  3. 3University of Molise, Campobasso, Italy
  1. Correspondence to Mario Vitale, mavitale{at}


Complementary medications and herbal medicine for weight loss have become very popular. We report a case of thyroid dysfunction following the ingestion of a kelp-containing marketed diet in a 45-year-old woman with no previous thyroid disease. Signs of hyperthyroidism occurred shortly after a kelp-containing diet. Hyperthyroidism lasted 2 months and was followed by an overt hypothyroidism. The thyroid scintiscan exhibited an extremely low uptake and colour-Doppler ultrasonography revealed multiple small areas of pulsatile flow. After 3 months of levothyroxine substitutive therapy, normal thyroid function was recovered after levothyroxine discontinuation. This clinical history is compatible with a case of iodine-induced thyrotoxicosis followed by prolonged block of the sodium–iodide symporter activity as a consequence of excessive iodine consumption from kelp. Consumers of marketed diets containing kelp or other iodine-rich ingredients should be advised of the risk to develop a thyroid dysfunction also in the absence of underlying thyroid disease.

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