I have several concerns about the letter to the Editor by Leung et al. (Feb. 26 issue). Scientific studies must provide method-ologic details or else the veracity of the results presented cannot be evaluated. Leung et al. provide no details regarding sample preparation and the method used for detecting and quantitating iodine content. A titrimetric method for measuring iodine, which dates back to 1932, or a modern method involving inductively coupled plasma-mass spectroscopy may have been used. Both methods are subject to interferences. In addition, the study draws conclusions about the iodine content in marketed products; these conclusions are not supported by a sampling plan and thus may not be justified. Tools for assessing the accuracy and precision of chemical measurements do exist; for instance, Standard Reference Material 3280 can be used to assign a certified value to the iodine content of multivitamins and multielement tablets. Although we support the need for ensuring nutritional adequacy, the lack of rigor in sampling and reporting casts doubt on the accuracy of the results of the study by Leung and colleagues.
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