Submitted to: Journal of Nutrition
Publication Type: Other
Publication Acceptance Date: 3/21/2003
Publication Date: 7/1/2003
Citation: Davis, C.D., Uthus, E.O. 2003. Does dietary selenium affect plasma homocysteine concentrations in humans? Journal of Nutrition. 133:2392.
Technical Abstract: The article by Venn et al (1). provides evidence that selenium supplements do not influence plasma total homocysteine (tHcy) concentrations in New Zealand men or women. It is certainly possible, as the authors conclude, that tHcy might be influenced by selenium status in populations with very low selenium status, such as in some parts of China but not in situations where mild deficiency exists, such as in New Zealand. In fact, our preclinical studies suggest that the greatest differences in tHcy are observed when comparing rats fed a severely deficient diet (<2 ng selenium/g diet) compared to those fed a moderately selenium-deficient diet (0.02 ug selenium/g diet)(2). Increasing selenium supplementation beyond 0.1 ug/g up to 2 ug Se/g, as either selenite or selenomethionine, did not lead to further changes in tHcy homeostasis (3,4). It should also be noted that investigating the relationship between dietary selenium and tHcy without considering other dietary components may lead to erroneous conclusions. For example, selenium deficiency has a more profound effect on tHcy in rats fed a folate-deficient diet than in rats fed a folate-adequate diet (5). Similarly, one might expect that other dietary factors such as methionine, vitamins B6 and B12, choline, and/or zinc may also affect this relationship. For this reason, we believe that investigating the relationship between dietary selenium and tHcy, particularly in clinical studies, requires the consideration of these modifying variables. Examining such interactions may prove exceedingly important to understanding the influence of selenium on tHcy. 1. Venn BJ, Grant AM, Thomson CD, Green TJ. (2003) Selenium supplements do not increase plasma total homocysteine concentrations in men and women. J Nutr 133:418-420. 2. Uthus EO, Yokoi K, Davis CD. (2002) Selenium deficiency in Fischer-344 rats decreased plasma and tissue homocysteine concentrations and alters plasma homocysteine and cysteine redox status. J Nutr 132:1122-1128. 3. Davis CD, Uthus EO, Finley JW. (2000) Dietary selenium and arsenic affect DNA methylation in vitro in Caco-2 cells and in vivo in rat liver and colon. J Nutr 130:2903-2909. 4. Davis CD, Uthus EO. (2002) Dietary selenite and azadeoxycytidine treatments affect dimethylhydrazine-induced aberrant crypt formation in rat colon and DNA methylation in HT-29 cells. J Nutr 132-292-297. 5. Davis CD, Uthus EO. (2003) Dietary selenium (Se) and folate affect dimethylhydrazine (DMH)-induced aberrant crypt formation, global DNA methylation and one-carbon metabolism in rats. FASEB J., in press.