EC Nutrition

During the last century, the focus on iodine nutrition was mainly to eradicate the worldwide iodine deficiency accompanied by goiter and cretinism. The importance however, on the role of iodine for the health of breast tissue had been out of this focus. Up to now, several in vitro as well as in vivo studies clearly demonstrate that iodine is not only important for the thyroid hormone homeo- stasis but probably higher iodine intake is necessary for the prevention of benign as well as malignant breast diseases and even might be an efficient adjuvant treatment for breast cancer. Epidemiological studies revealed that women with high iodine intake, especially through seaweed consumption have 5-times less breast cancer compared to women with low iodine intake. Iodine deficiency in the rats induces both, thyroid and breast susceptibil- ity for atypia, dysplasia and hyperplasia. Female rats in iodine deficiency not only develop thyroid nodules but also nodules and even carcinomas of the breast. Furthermore, iodine or watery extracts of seaweed reduces the incidence of chemically induced breast cancer in rodents. Iodine treatment of women with mastopathy lead to a remission of disease symptoms. The iodine metabolism in thyroid and breast tissue is comparable, especially the pathways that control growth and apoptosis. Typically, breast tissue of lactating women expresses the same sodium-iodine symporter (NIS), like the thyroid, but not breast tissue from non-lactating women. In human breast cancer cell lines, it could be shown that molecular iodine, but not iodide inhibit growth and induces apoptosis. Iodine exposure of thyroid cells as well as breast cancer cells create a specific d-iodolactone, an io- dinated product of the arachidonic acid of the cell membrane. This d-iodolactone seems to be involved in the antiproliferative and apoptotic pathway of both, thyroid as well as epithelial breast cancer cells. Prospective controlled studies in humans are lacking, but the results of the in vitro as well as experimental animal studies should emphasize the need for adjuvant treatment of women with breast cancer with either seaweed extracts or iodine.

keywords: Iodine; Delta-Iodolactone; Goiter; Breast Cancer; Mastopathy; IGF-1

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