Goitrogenic compounds like isothiocyanates can inhibit thyroid function, especially when selenium is deficient. Which statement is correct?

• A. They have no effect on thyroid function
• B. They may inhibit thyroid function
• C. They always cause thyroid failure
• D. They enhance thyroid function

Answer: (B)

Goitrogenic compounds can interfere with thyroid hormone production, and their impact depends on micronutrient status, especially selenium. Isothiocyanates, derived from cruciferous vegetables, may hinder thyroid function by reducing iodine uptake and disrupting hormone synthesis. When selenium is deficient, the thyroid is less able to convert T4 to the active T3 and to protect itself from oxidative stress, making the inhibitory effect more likely. Because of this, the effect is not guaranteed or universal; they may inhibit thyroid function in susceptible individuals, rather than always causing thyroid failure or never affecting it, and they do not enhance thyroid function.