Concentrations of thiocyanate and goitrin in human plasma, their precursor concentrations in brassica vegetables, and associated potential risk for hypothyroidism

Abstract

Brassica vegetables are common components of the diet and have beneficial as well as potentially adverse health effects. Following enzymatic breakdown, some glucosinolates in brassica vegetables produce sulforaphane, phenethyl, and indolylic isothiocyanates that possess anticarcinogenic activity. In contrast, progoitrin and indolylic glucosinolates degrade to goitrin and thiocyanate, respectively, and may decrease thyroid hormone production. Radioiodine uptake to the thyroid is inhibited by 194 lmol of goitrin, but not by 77 lmol of goitrin. Collards, Brussels sprouts, and some Russian kale (Brassica napus) contain sufficient goitrin to potentially decrease iodine uptake by the thyroid. However, turnip tops, commercial broccoli, broccoli rabe, and kale belonging to Brassica oleracae contain less than 10 lmol of goitrin per 100-g serving and can be considered of minimal risk. Using sulforaphane plasma levels following glucoraphanin ingestion as a surrogate for thiocyanate plasma concentrations after indole glucosinolate ingestion, the maximum thiocyanate contribution from indole glucosinolate degradation is estimated to be 10 lM, which is significantly lower than background plasma thiocyanate concentrations (40-69 lM). Thiocyanate generated from consumption of indole glucosinolate can be assumed to have minimal adverse risks for thyroid health.

Use of elicitation in the cultivation of Bimi® for food and ingredients

“…Another interesting fact was the low amount of progoitrin found in Bimi. This GLS seems to interfere in iodine utilization in the synthesis of thyroid hormones . Furthermore, Brassica species low in GLSs have been harvested for broiler diets in order to avoid this detrimental effect .…”

“…This GLS seems to interfere in iodine utilization in the synthesis of thyroid hormones. 41 Furthermore, Brassica species low in GLSs have been harvested for broiler diets in order to avoid this detrimental effect. 42 In this work, progoitrin could only be detected in trace amounts by HPLC-DAD-ESI-MS 2 , even when the plants were treated with elicitors.…”

Never have been and here again…

“…Все они богаты глюкозинолатом, веществом из которого синтезируется сульфорафан и фенетиловые и индольные изотиоцианаты, обладающие антиканцерогенными свойствами. Однако глюкозинолат также метаболизируется в тиоцианат, тормозящий синтез гормонов щитовидной железы [18]. Хотя потребление овощей семейства Brassica считается полезным для здоровья, частое их поедание в большом количестве может вызвать или усилить уже существующий гипотиреоз.…”

Biotechnological approaches in glucosinolate production

“…Cabbage is rich in β‐hydroxyalkenyl GLSs, which upon hydrolysis gives rise to oxazolidine‐2‐thiones. The goitrogenic symptoms observed in the rabbits were attributed specifically to these GLS hydrolysis products, which can hinder iodine uptake by the thyroid (Felker et al ). In other studies, induction of goiter, reduced fertility, and growth inhibition were observed in pigs, poultry, and rodents and to a lesser extent in ruminants and fish (for an extensive review see Tripathi and Mishra ).…”