Salt Iodine Variation within an Extended Guatemalan Community: The Failure of Intuitive Assumptions

Abstract

Guatemalan law mandates an iodine concentration from 30 to 700 parts per million (ppm) in all table salt offered in local commerce. Forty-four specimens of salt were collected in urban and rural sectors of a county on the outskirts of the capital of Guatemala and analysed for their iodine content by an iodate titration method. The concentrations ranged from 1 to 117 ppm, (mean ± SD 26.6 ± 21.7 ppm, median 24 ppm). Salt samples with iodine in both the adequate and the inadequate ranges were found in each of five subjurisdictions (township and four hamlets), and the median concentration was equivalent at all sites, without an urban-to-rural gradient. Similarly, the mandated iodine concentration was no more likely to be found in salt packaged under a brand name with a commercial label than in salt in a plain, unlabelled package. The findings place in relief the continuing difficulties in Guatemala in the effort to provide a universally protective level of iodine in table salt.