Journal of Analytical Toxicology, Vol. 16, July/August 1992 Determination of Serum Levels of Dietary Thiocyanate Fat ima O lea * and Pi lar Par ras

A spectrophotometric method was used to determine thiocyanate (SCN-) levels In human serum, In an attempt to relate serum levels of this ion to the dietary intake of vegetables of the genus Brassica. Thlocyanate Ion was measured before and after a one-week period during which the subjects ate a diet rich In these vegetables. We also determined the serum increase in SCN- 2 h after the administration of 0.5 g KSCN. In t roduct ion The latest report of the Food and Agriculture Organization of the United Nations ( 1) sets the number of persons with endemic goiter at approximately 200 million worldwide, the most seriously affected regions being the Andes, the Himalayas, and other moun-tainous zones. In Europe, areas of high prevalence include the Swiss Alps and the Penibetic Range in southern Spain. Although an insufficient iodine supply seems to be the principal dietetic ause of goiter, other causal factors in the diet should not be neglected. These sources include: (a) cyanide glycoside ions, e.g. amygdalin from almonds (Prunus amigdalis) and linamarin from cassava (Maniot utilissima). Hershman et al. (2) studied the incidence of cassava on endemic goiter in mountainous re-gions of Vietnam and established a clear relationship between the urinary iodine/urinary SCN- ratio and the prevalence of goiter: The I-/SCN- ratio was significantly higher in areas where goiter was not endemic, in comparison to zones of endemism. (b) Phe-nolic derivatives of glucosides in peanut (Arachis hipogea) nd cashew nut (Anacordum occidentalis). (c) Alkyl sulfides in mem-bers of the genus Allium (garlic, onion, leeks, etc.). (d) Thio-cyanate ion from glucosides in members of the family Cru-cifereae consumed by animals and man. Iwarsson (3) showed cow's milk to be a direct vehicle for SCN- in the human diet. Several varieties of the genus Brassica consumed by man, in