“Myelodysplasia,” Myeloneuropathy, and Copper Deficiency–Reply–I

Abstract

I agree with Dr Klevay, that some individuals may have a higher-than-average copper requirement. This may predispose them to the neurologic and hematologic manifestations of acquired copper deficiency. There is growing concern that the desired copper intake may not be met by the typical Western diet.1Klevay LM Lack of a recommended dietary allowance for copper may be hazardous to your health.J Am Coll Nutr. 1998; 17: 322-326Crossref PubMed Scopus (70) Google Scholar, 2Pang Y MacIntosh DL Ryan PB A longitudinal investigation of aggregate oral intake of copper.J Nutr. 2001; 131: 2171-2176PubMed Scopus (41) Google Scholar Rather than decreased copper intake being responsible for copper deficiency in some patients, I believe that a primary copper-absorption defect may be the cause. This defect may be due to prior gastrointestinal surgery, a malabsorption state, or an unidentified copper transport defect.3Kumar N Ahlskog JE Gross Jr, JB Acquired hypocupremia after gastric surgery.Clin Gastroenterol Hepatol. 2004; 2: 1074-1079Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar Studies in yeast have shown that copper-transport mechanisms are high-affinity pathways that are active in conditions of low copper concentration; these pathways can be bypassed by increasing the concentration of copper salts in the medium.4Valentine JS Gralla EB Delivering copper inside yeast and human cells.Science. 1997; 278: 817-818Crossref PubMed Scopus (189) Google Scholar Improvement in serum copper level by oral copper administration has been observed, despite a possible “intestinal block.”5Kumar N Gross Jr, JB Ahlskog JE Copper deficiency myelopathy produces a clinical picture like subacute combined degeneration.Neurology. 2004; 63: 33-39Crossref PubMed Scopus (258) Google Scholar The relative rarity of copper deficiency suggests that it is not simply a result of reduced copper intake. The various possible causes of a copper-absorption defect may result in hypocupremia, even with a dietary copper intake that otherwise would have been optimal. I agree with Dr Klevay, that there is a need to accurately define copper requirements in different population groups.