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The Geographical Review January 1998, Vol. 88 (1), pp. 1-28 The Iodine Factor in Health and Evolution Jerome E. Dobson ABSTRACT Iodine is essential for modern humans and may have been essential for Neandertals as well. Today about 30 percent of the world'spopulation is at risk of iodine deficiency disorders (IDD), 750million people suffer from goiter, 43 million have IDD-relatedbrain damage and mental retardation, and 5.7 million are afflictedby cretinism, the most severe form of IDD. Distinctive Neandertalskeletal traits are identical to those of modern humans who sufferfrom cretinism. Cro-Magnon Venus figurines also exhibit distinctivetraits associated with cretinism among modern humans. This newevidence, coupled with recent mitochondrial DNA findings, suggeststhat a single genetic alteration, which improved the ability ofthe thyroid gland to extract and utilize iodine, may account fordifferences between Neandertals and modern humans. Late Pleistocenehuman evolution, consequently, may be explained by several alternativeinterpretations involving iodine pathology and/or biological adaptation.Speciation may have resulted from the geographical isolation of inland populations. Keywords: cretinism, Cro-Magnon, Europe, evolution, iodine, medical geography, Neandertal, Venus figurine. Dr. DOBSON is a member of the senior development staff at the Oak Ridge National Laboratory. To contact the author: Dr. Jerome E. Dobson Bldg 4500-N, MS 6237 P.O. Box 2008 Oak Ridge National Laboratory Oak Ridge, TN 37837-6237