We agree with Joel Ray and David Cole regarding the relative practical value of serum total homocysteine and methylmalonic acid in elderly patients with suspected cobalamin deficiency. Although testing for serum holotranscobalamin is not routinely available in many countries, we believe that it may be appropriate in future as a routine clinical test for cobalamin deficiency. However, to date, a consensus on the definition for cobalamin deficiency, especially among elderly patients, has not been achieved.1 Thus, in our experience, serum total homocysteine is currently a helpful, inexpensive indicator of true (tissue) cobalamin deficiency, as suggested in our article.2
We agree with Peter Wetterberg's comments on oral cobalamin. However, the usefulness of oral cobalamin therapy has only recently been documented, starting in 1995, with studies that meet the criteria of evidence-based medicine.3,4,5,6
We read with great interest Jonathan Prousky's comments, although we have no experience with the therapies he describes. Nevertheless, we believe that this information indirectly supports the concept of food-cobalamin malabsorption.7
Emmanuel Andrès Department of Internal Medicine University Hospital of Strasbourg Strasbourg, France
Footnotes
Competing interests: None declared.
References
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