Iodine Content of Human Skim Milk from Goitrous and Non-goitrous Regions

Abstract

Published figures for the iodine content of cow's and women's milk are not consistent. The foreign investigators report for cow's milk, 1γ-3γ% and for human milk after the fifth lactation day 2γ-4γ%. American investigators find that the percentage in cow's skim milk, calculated on the dry basis, may vary between 14.0γ and 130.0γ%. This investigation includes a study of the iodine content of the milk from mothers in Detroit, a goitrous region, and from mothers in Boston, a non-goitrous region. The mothers were normal and showed no signs of thyroid hyperplasia. The value of iodine was determined in the milk of mothers at varying intervals during the mature lactation period. The calcium and inorganic soluble phosphates were also determined and compared with the fluctuations found for iodine. The milk was obtained through the courtesy of the Detroit Mother's Milk Bureau and The Directory for Mother's Milk, Boston. Nine cases were studied from the former and 10 cases from the latter. Micro methods were used for the determination of calcium, inorganic soluble phosphates, and iodine. Samples of one ounce were received and a 10 cc. portion of this was needed for the micro-iodine estimation, as described by the author.3, 4 The calcium and inorganic soluble phosphates were determined on the trichloracetic acid filtrates from 2 cc. of skimmed milk. Calcium was estimated by the method of Clark, the inorganic soluble phosphates by the method of Benedict and Theis. The results represent analyses of 295 samples of milk. The average iodine content of human skim milk may vary among women and at different times during the lactation period from 6.0γ to 23.0γ%. The average is 12.4y. There is a marked variation in individuals.