Iodine and The Origins of Human Diet and Brain
In his thorough review of the Paleolithic origins of the human diet, Cordain et al may have missed iodine and its role, according to Stephen Cunnane (1;2). Cunnane writes that “1 of the 2 nutrients (the other is iron)” that modern humans most often find themselves deficient in is iodine.
Human brain development, Cunnane explains, is heavily affected by sufficient iodine intake; inland populations of developed countries have avoided brain impairment only through intake of iodized table salt (2).
Cunnane suggests that shore-based food may have been part of the diet of early humans because otherwise iodine and other “brain-selective nutrients” such as docosahexaenoic acid and iron may not have allowed the human brain to evolve at all (2).
Anthropologists appear to be in agreement with Cunnane that the coastline may have been a critical point in the human story. One of the oldest-known human stone tool sites, in fact, was found in what would have been a coastal environment 125,000 years ago in eastern Africa (3).
1. Cordain L, Eaton SB, Sebastian A et al. Origins and evolution of the Western diet: health implications for the 21st century. Am J Clin Nutr 2005;81:341-54.
2. Cunnane SC. Origins and evolution of the Western diet: implications of iodine and seafood intakes for the human brain. Am J Clin Nutr 2005;82:483-4.
3. University Of Toronto (2000, June 1). Stone Tools Reveal Ancient Seafood Diet. ScienceDaily. Retrieved September 11, 2009, from http://www.sciencedaily.com/releases/2000/05/000531070849.htm