ABSTRACT

Goitrogens are compounds contributed by plants, drugs, or other chemicals that can result in the formation of goiter. Deficiency of iodine increases the responsiveness of the thyroid gland to goitrogens and may result in abnormal thyroid functioning. Such foods include plants from diverse families, primarily cruciferous vegetables, soy-based foodstuffs, fruits, and starchy plants. Many forms of antinutritional factors have been found in these species for example glucosinolates, cyanogenic glycosides, flavonoids etc. Plants containing glucosinolates also contain specific β-thioglucosidase (denoted as myrosinase) and when plant parts are damaged the enzyme is released which hydrolyzes glucosinolates. These hydrolysis products (thiocyanates, isothiocyanates, nitriles, epithionitriles, oxazolidinethiones) can compete with iodine uptake and the biosynthesis of thyroid hormones (T3 and T4), resulting in hypothyroidism and thyroid gland enlargement. Similarly, cyanogenic glycosides are mainly present in fruits and certain starchy plants, which can also compete with iodine for thyroid absorption. On the other hand, goitrogenic flavonoids are mostly contributed by soy-based foods and they can hinder thyroid peroxidase function. Goitrogenic ability is assessed not only by the amount of goitrogenic substances in a food, but also by how it is processed before consumption and the nutritional status of the consumer’s body. Numerous processing approaches have been attempted to eliminate or decrease glucosinolate content and to mitigate glucosinolate related negative effects in animals as well as humans.