Glucosinolates are compounds that act as goitrogens and have an anti-thyroid effect by inhibiting the gland's ability to absorb iodine. Iodine is needed by the thyroid as a building block for thyroid hormone. It's thought that being able to detect -- and, due to an aversion, avoid -- glucosinolates found naturally in food could provide a biological advantage to the more than 1 billion people worldwide who have low iodine status, and face a risk of thyroid disease.
The study genotyped 35 participants into three groups: sensitive to glucosinolates, insensitive, and intermediate. The participants then rated the bitterness of vegetables, including 17 glucosinolate-containing vegetables (which included watercress, broccoli, bok choy, kale, kohlrabi, and turnip) and 11 non-glucosinolate foods included radicchio, endive, eggplant and spinach. (Click here for a complete list of the glucosinolate-containing antithyroid vegetables tested.)
Those who were "sensitive" rated the glucosinolate-containing vegetables as 60% more bitter the insensitive group. The groups rated the other vegetables equally bitter.
According to senior author Paul Breslin, "the sense of taste enables us to detect bitter toxins within foods, and genetically-based differences in our bitter taste receptors affect how we each perceive foods containing a particular set of toxins."
Breslin does not recommend eliminating goitrogenic vegetables from the diet however. Says Breslin: "The contents of the veggies are a double-edged sword, depending upon the physiological context of the individual eating them."
Source: Sandell, Mari A. and Paul A.S. Breslin. "Variability in a taste-receptor gene determines whether we taste toxins in food." Current Biology, 2006, 16, R792-R794.