Previous reports on pernicious anemia treatment suggested that high folic acid intake adversely influences the natural history of vitamin B-12 deficiency, which affects many elderly individuals. However, experimental investigation of this hypothesis is unethical, and the few existing observational data are inconclusive. With the use of data from the 1999-2002 National Health and Nutrition Examination Survey (NHANES), we evaluated the interaction between high serum folate and low vitamin B-12 status [ie, plasma vitamin B-12 < 148 pmol\/L or methylmalonic acid (MMA) > 210 nmol\/L] with respect to anemia and cognitive impairment. With subjects having both plasma folate < or = 59 nmol\/L and normal vitamin B-12 status as the referent category, odds ratios for the prevalence of anemia compared with normal hemoglobin concentration and impaired compared with unimpaired cognitive function were 2.1 (95% CI: 1.1, 3.7) and 1.7 (95% CI: 1.01, 2.9), respectively, for those with low vitamin B-12 status but normal serum folate and 4.9 (95% CI: 2.3, 10.6) and 5.0 (95% CI: 2.7, 9.5), respectively, for those with low vitamin B-12 status and plasma folate >59 nmol\/L. Among subjects with low vitamin B-12 status, mean circulating vitamin B-12 was 228 pmol\/L for the normal-folate subgroup and 354 pmol\/L for the high-folate subgroup. We subsequently showed increases in circulating homocysteine and MMA concentrations with increasing serum folate among NHANES participants with serum vitamin B-12 < 148 pmol\/L, whereas the opposite trends occurred among subjects with serum vitamin B-12 > or = 148 pmol\/L. These interactions, which were not seen in NHANES III before fortification, imply that, in vitamin B-12 deficiency, high folate status is associated with impaired activity of the 2 vitamin B-12-dependent enzymes, methionine synthase and MMA-coenzyme A mutase.\n<\/div>\n","protected":false},"excerpt":{"rendered":"

Editorial: Am J Clin Nutr Fecha: 01\/02\/2009 Selhub J, Morris MS, Jacques PF, Rosenberg IH. Acceso al enlace publicador Previous<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[4],"tags":[],"_links":{"self":[{"href":"https:\/\/awge.doctime.es\/index.php\/wp-json\/wp\/v2\/posts\/328"}],"collection":[{"href":"https:\/\/awge.doctime.es\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/awge.doctime.es\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/awge.doctime.es\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/awge.doctime.es\/index.php\/wp-json\/wp\/v2\/comments?post=328"}],"version-history":[{"count":1,"href":"https:\/\/awge.doctime.es\/index.php\/wp-json\/wp\/v2\/posts\/328\/revisions"}],"predecessor-version":[{"id":724,"href":"https:\/\/awge.doctime.es\/index.php\/wp-json\/wp\/v2\/posts\/328\/revisions\/724"}],"wp:attachment":[{"href":"https:\/\/awge.doctime.es\/index.php\/wp-json\/wp\/v2\/media?parent=328"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/awge.doctime.es\/index.php\/wp-json\/wp\/v2\/categories?post=328"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/awge.doctime.es\/index.php\/wp-json\/wp\/v2\/tags?post=328"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}