Goitrogens in Milk

SUMMARY 1. English kale, used to a great extent as a fodder for cows during the winter months, contains a substance which causes epithelial hyperplasia in the thyroid of rabbits. 2. The milk of cows fed either on English kale or on hay contains a substance which temporarily suppresses the uptake of 131I by the human thyroid. 3. The 'goitrogenic' effect of 'hay milk' is transient, and there is at present no evidence that it is clinically significant. That of 'kale milk', even if it is significant in fresh milk, is absent from deep-frozen milk. Further experiments are in progress to determine the goitrogenic properties, if any, of fresh kale milk.