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March 19, 1997

Folate Supplementation and the Risk of Masking Vitamin B12 Deficiency-Reply

Author Affiliations

Jean Mayer Human Nutrition Research Center on Aging at Tufts University Boston, Mass

JAMA. 1997;277(11):884-885. doi:10.1001/jama.1997.03540350034027

In Reply.  —Dr Brantigan raises an important concern from the point of view of individual patients. Although our analysis of data from the Framingham Heart Study does suggest that the benefits of folate fortification at the approved level of 140 μg per 100 g of grain-cereal product outweigh the risks of masking anemia due to vitamin B12 deficiency, we do not mean to imply that there are no risks. Of 694 subjects with complete data, we found low vitamin B12 concentrations (<185 pmol/L) in 18.5%, demonstrating that poor vitamin B12 status is indeed an important problem. However, only 2.3% and 0.9% of patients had low hemoglobin or high mean corpuscular volume, respectively, suggesting that anemia is clearly an inadequate screening indicator for vitamin B12 status in this population. High projected folate intake (>800 μ/d) in combination with both low vitamin B12 concentration and anemia were not seen