Dietary deficiency of vitamin B12 is associated with low serum cobalamin levels in non-vegetarians.

A prospective study of 106 patients with low serum cobalamin (vitamin B12) levels showed that, in 37, it was unexplained. The dietary intake of the vitamin was assessed in these patients by questionnaire and was found to be low in 10 (37%). None of these patients was vegetarian and they were of varying age and social circumstance. Dietary deficiency may be the sole cause of a low serum cobalamin in a significant proportion of non-vegetarians. An assessment of dietary intake should be part of the investigation of cobalamin deficiency.