What foods are naturally high in iodine?

Iodine is a component of almost every living plant and animal. . In general, foods from the sea contain the most iodine, e.g., seaweed and spirulina, followed by meats, and then green foods. Of all foods seaweed, like kelp, is the most famous and reliable source of natural iodine, however egg and dairy products can also be good sources.

Seaweed has such a large proportion of iodine compared to dietary minimum requirements, that it is primarily known as a source of this nutrient. The highest iodine content is found in brown algae, with dry kelp ranging from 1500-8000 ppm (parts per million) and dry rockweed (Fucus) from 500-1000 ppm. In most instances, red and green algae have lower contents, about 100-300 ppm in dried seaweeds, but remain high in comparison to any land plants. Daily adult requirements, currently recommended at 150 µg/day, could be covered by very small quantities of seaweed. Just one gram of dried brown algae provides from 500-8,000 µg of iodine and even the green and red algae (such as the purple nori that is used in Japanese cuisine) provides 100-300 µg in a single gram.

What Regulates Your Thyroid?

The principal regulator of thyroid function is the pituitary hormone (thyroid-stimulating hormone), which in turn is controlled by positive input from the hypothalamic hormone (thyrotropin-releasing hormone) and by negative input from thyroxine and triiodothyronine. Thyroid-stimulating hormones bind to G-protein (molecular switches)-coupled receptors in the surface membranes of thyroid follicular cells (Goodman 2003), which leads to increases in both the cyclic adenosine monophosphate (cAMP) and diacylglycerol/inositol trisphosphate second messenger pathways (Goodman 2003). Triiodothyronine, rather than thyroxine, probably is responsible for the feedback response for thyroid-stimulating hormone production (Schneider et al. 2001). Some triiodothyronine, the active form of thyroid hormone, is secreted directly by the thyroid along with thyroxine, but most triiodothyronine is produced from thyroxine by one of two deiodinases (Types I and II1) in the peripheral tissue (Schneider et al. 2001; Larsen et al. 2002; Goodman 2003). Triiodothyronine enters the nucleus of the target cells and binds to specific receptors which activate specific genes.

In the 1930s, Goldemberg was the first to introduce fluorine therapy for hyperthyroidism and Basedow's disease. . Other research has shown that regular fluoride intake in the range of 5 mg/day, which is now common with water fluoridation, can reversibly inhibit normal thyroid activity, even with a good diet.

Studies are coming to light that fluoridation is damaging the DNA, creating cancer and other disorders. (Yaming Ge et. al., 2005) Fang et al showed a high incidence of thyroid cancer (15.6%) in iodine deficient rats and mice compared to a zero percent incidence in controls.