Iodine content in the marketed products of iodized salt: a descriptive study in southern Sri Lanka

Background: Monitoring of the iodization programmes is crucial not only to ensure that the salt contains sufficient amount of iodine but not excessive amounts that lead to adverse health consequences. Countries usually recommend minimum standards for the iodine content of salt at the production level, but less frequently establish standards at the consumer level. Sri Lankan standards recommended salt should have 15.0-30.0 ppm of fortified iodine at the retail level. Objective: To assess the iodide content in crystal and table (powder) salt preparations for the human consumption in Southern Sri Lanka. Methods: Commercially available packets of both crystal and table salt were purchased from randomly selected permanent (57 retail shops and 24 supermarkets) and temporary (8, weekly fairs) shops and analyzed for the iodine content. Information on the storage conditions, the shelf life of the samples was also recorded. Results: There was a total of 89 packets of salt which comprising of crystal (n=30) and powder (n=59) packets belonged to 42 different brands (15 and 27 brands for crystal powder salts respectively). Over 74% of packets had one year and the remainder (26%) had 18 to 24 months of shelf life. The median iodide level of the total sample was 20.40 ppm (range 0.0 to 73.81 ppm) whereas the median iodide level of crystal salt was 18.89 ppm (range 3.70 to 73.81 ppm) and table salt was 21.63 ppm (range 0.0 to 41.24). It was revealed that 21(23.6%) packets of salt (11 crystal and 10 table salts respectively) had iodide levels below 15.0 ppm and 11(12.4%) packets of salt (4 crystal and 7 table) had iodine level above the recommended range of 30.0 ppm. Altogether 22 (52.4%) brands did not have iodine levels within the recommendations and in fact, one powder salt packet did not contain a detectable amount of iodide. Conclusions: Establishing a precise sustainable monitoring system of salt iodization at the production level is important in maintaining iodine nutrition at the optimum level.