Folic acid as ultimate in disease prevention: Beware of vitamin B12 deficiency

doi:10.1136/bmj.328.7442.769

BMJ 2004;328:769 (27 March), doi:10.1136/bmj.328.7442.769

Letter

Folic acid as ultimate in disease prevention

Beware of vitamin B12 deficiency

The first 150 words of the full text of this article appear below.

EDITOR—In response to the review by Lucock on folic acidsupplementation,¹ we have a word of caution about possible concomitantvitamin B12 deficiency, which may also cause raised concentrationsof homocysteine.

Vitamin B12 deficiency can be subtle, manifesting only as anincrease in concentrations of homocysteine and methylmalonicacid in blood and urine, with concentrations of vitamin B12at the lower limit of normal.² Vitamin B12 concentration variesin different populations. The US NHANES III survey found a meanserum B12 value of 518 pg/ml, and 3% of the population had aconcentration of less than 200 pg/ml.³ In Israel we reporteda vitamin B12 deficiency of 30% in 130 serial patients undergoingcoronary angiography.⁴ Health maintenance organisations in Israelresponded to the widespread deficiency of vitamin B12 by loweringthe normal values of their laboratories.