Long-term readers here may be aware of my caution over supplementing with iodine. That may be right or wrong. I worry that it is so very easy to take vastly more than we need and the consequences are anything but clear. The abstract below certainly raises the question of our iodine sufficiency here in the UK.
A great pity that it only digs into previous papers and does not report new research. But it does very clearly call for such research to be performed. We really do need proper answers.
Eur J Endocrinol. 2013 Oct 2. [Epub ahead of print]
Impact of iodine supplementation in mild-to-moderate iodine deficiency: systematic review and meta-analysis.
Taylor PN, Okosieme OE, Dayan CM, Lazarus JH.
P Taylor, Thyroid Research Group, Cardiff University School of Medicine, Cardiff, United Kingdom.
Abstract
Background
Although the detrimental effects of severe iodine deficiency are well recognised the benefits of correcting mild-to-moderate iodine deficiency are uncertain.
Objectives
We undertook a systematic review of the impact of iodine supplementation in populations with mild-moderate iodine deficiency.
Methods
We searched Medline and the Cochrane library for relevant articles published between January 1966 and April 2013 which investigated the effect of iodine supplementation on maternal and newborn thyroid function, infant neurodevelopment, and cognitive performance in school-age children. The quality of studies was graded and eligible trials were evaluated in meta-analysis.
Results
Nine randomised controlled trials and 8 observational studies met the inclusion criteria. Controlled trials on infant neurodevelopment were lacking; gestational iodine supplementation reduced maternal thyroid volume and serum thyroglobulin and in some studies prevented a rise in serum TSH. None of the intervention trials recorded an excess frequency of thyroid dysfunction in contrast to observational studies. A pooled analysis of two RCTs which measured cognitive function in school age children showed modest benefits of iodine supplementation on perceptual reasoning (standardised mean difference [SMD] 0.55, 95% confidence interval [CI] 0.05, 1.04; P=0.03) and global cognitive index (SMD 0.27, 95% CI 0.10, 0.44; P=0.002) with significant heterogeneity between studies.
Conclusion
Iodine supplementation improves some maternal thyroid indices and may benefit aspects of cognitive function in school-age children, even in marginally iodine deficient areas. Further large prospective controlled studies are urgently required to clarify these findings and quantify the risk/benefits of iodine supplementation in regions previously believed to be iodine sufficient such as the UK.
PMID: 24088547 [PubMed - as supplied by publisher]
ncbi.nlm.nih.gov/pubmed/240...
Rod
Image is: A waitress, dressed as Officer Sweetheart, Donut Patrol for Halloween, filling salt shakers with Morton iodised salt at Elmo's Diner in Durham, North Carolina. AKA Nicole pouring salt at Elmo's Diner.jpg
