Determine the Food Sources of Iodine?

Please note that unlike other minerals studied so far, like selenium, the iodine concentration in foods is highly variable and also depends on the concentration of iodine content of soil in that region. The iodine present in the upper crust of the earth is leached by glaciation and repeated flooding, and is carried to the sea. Seawater is, therefore, a rich source of iodine. The seaweed located near coral reefs has an inherent biological capacity to concentrate iodine from the sea. The average iodine content of foods (fresh and dry basis) is given in Table.

The amount of iodide in drinking water is an indicator of the iodide content of the rocks and soils of a region and it parallels the incidence of iodine deficiency among the inhabitants of that region. In general, iodine deficient areas have water iodine levels below 2 mcg/L as in Nepal and Sub-Himalayan India (0.1 -1.2 mcg/L) compared with levels of 9 mcg/L in the city of Delhi, which is not iodine deficient.

Table: Average iodine content of foods (mg/kg)

In addition to water, iodine is also contributed by sea foods, as mentioned above; however, a large difference in the content exists between sea water fish and fresh water fish. Sea fish contain about 300-30,000 mcg iodine/kg in contrast to only 20-40 mcg iodine/kg in fresh water fish. Also, food additives used as bread dough oxidizers or conditioners can contribute to the iodine content of the diet. You must be acquainted with the physiological significance of iodine by now.