Ascorbic Acid and Vitamin B12 Deficiency

Abstract

To the Editor.— Drs Herbert and Jacob made the observation that ascorbic acid (vitamin C) in quantities in excess of 0.5 gm will destroy between 50% and 95% of vitamin B 12 content in food (230:241, 1974). During the past six months, we have been able to assess the vitamin B 12 concentrations in serum as well as in the peripheral blood smears in 90 subjects at Cleveland Metropolitan General Hospital, all taking more than 500 mg of ascorbic acid daily. These subjects responded to publicity concerning the possible danger of megadose ascorbic acid ingestion. Three subjects, aged 50 to 60 years, had been taking a minimum of 1,000 mg of ascorbic acid with each meal for more than three years. These three subjects did show subnormal serum vitamin B 12 concentrations ranging from 65 to 100 pg/ml. Two of the three had hypersegmented neutrophils and occasional ovalomacrocytes, although none