Santos et al recently published a Cochrane Review, investigating the addition of iodine to foods other than salt to prevent diseases caused by inadequate iodine intake. Eleven studies met the authors’ inclusion criteria, seven randomised control trials (RCTs), three cluster non-RCTs and one randomised cross-over study.
The majority were carried out in school aged children (n=7), with the remaining carried out in women of reproductive age (n=3) and infants (n=1). Many different foods were fortified with iodine including biscuits, milk, fish sauce and yoghurt, with iodine fortification ranging from 35 to 220 micrograms/day, and trial duration of 11 days to 48 weeks.
Outcomes measured included goitre prevalence, physical development and urinary iodine. The effect of fortification of foods on goitre prevalence and physical development was uncertain, however the pooled results for urinary iodine concentration in the RCT studies showed a significant increase with fortification (not evident for the non-RCT studies).
Authors concluded that the effect of iodine fortification of foods, beverages and condiments other than salt is uncertain for goitre and physical development outcomes, and therefore more research is needed.
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