Foods are composed of a variety of natural compounds with nutritional
effects. However, some of them may also possess anti-nutritional and thyroid toxic
effects, such as glucosinolate compounds, which are present in foods derived from
higher plants. Currently, functional foods have been incorporated as sources of nutrients
to our diet in order to meet certain nutritional requirements not present in conventional
food; their effects on the thyroid gland are unknown and should be determined in order
to perform a complete risk assessments of these foods. Food supplements, which are
used widely by the population in many countries, are another source of nutrients,
especially minerals and trace elements such as iodine and zinc that are necessary for the
proper functioning of the thyroid gland, but if their use is not controlled they may
induce alterations of the thyroid system. Furthermore, many of these dietary
supplements also contain plants, algae and soybean in their composition that can exert
harmful effects on normal thyroid function. Finally, during food processing different
chemical compounds such as nitrate and erythrosine could be used, which could also
induce harmful effects on the thyroid system. This chapter will discuss all of the foods
and supplements mentioned above and their possible effects on normal thyroid function.
Keywords: Dietetic supplements, food, food additives, functional foods.
