Ascorbic Acid and Vitamin B12

Abstract

To the Editor.— In their BRIEF REPORT, "Ascorbic Acid and Vitamin B₁₂" in this issue ofThe Journal, Newmark et al (p 2319) allege that the vitamin B₁₂levels we found in foods were "inaccurate." The Table in their article shows that the allegation is not so, since it rests on comparison of foods we extracted in 1974, which happened to have low vitamin B₁₂content, with foods we extracted in 1977, which had average vitamin B₁₂content. Their Table also shows that one half of the food vitamin B₁₂extractable by the Veterans Administration methods appears to become unextractable (or destroyed) by that method of extraction (and assay) in the presence of 0.5 g of ascorbic acid. Because humans do not add the cyanide or metabisulfite of the Association of Official Analytical Chemists (AOAC) and British assay methods to their food to extract the