Use of oral iodized oil to control iodine deficiency in Indonesia

Iodine deficiency is a leading cause of preventable mental retardation and universal salt iodization has been adopted as the main strategy for its control. However additional strategies are required where iodized salt cannot be made available in the short term or only with difficulty in the long term. Oral iodized oil supplementation is useful for this purpose. The aim of the work described in this thesis was to compare the efficacy of different preparations of oral iodized oil for controlling iodine deficiency. In addition, the performance of different outcome indicators of iodine deficiency, the impact of nutritional status and iodine supplementation on cognitive performance, as well as the effectiveness of salt iodization in the population were investigated. The studies were carried out in school children aged 8-10 y living in an endemic iodine deficient area in Indonesia.A single oral dose of iodized oil prepared from peanut oil which is rich in oleic acid resulted in three times higher retention of iodine and twice the length of protection than iodized oil prepared from poppyseed oil which has less oleic acid and more linoleic acid. Thus iodized oils based on oleic acid rich oils should be given preference to iodized poppyseed oil in programs to control iodine deficiency.Urinary iodine concentration and thyroid volume measured by ultrasound were found to be the most useful indicators for assessing iodine status and measuring the impact of iodized oil supplementation among iodine deficient school children. However thyroid palpation still has a useful place in assessing iodine status because no sophisticated equipment is required. Iodine status as measured by urinary iodine concentration at baseline and stunting were found to be related to the improvement of cognitive performance when children were dosed with iodized oil. The use of iodized salt, which was correlated with urinary iodine concentration and thyroid volume, resulted in improvement of the iodine status of the population studied. Apart from promulgation enabling legislation, much effort needs to be expended to increase the success of salt iodization for controlling iodine deficiency.