ABSTRACT
Cobalt is an essential trace element. It occurs in vitamin B12, which is required by all mammals for hemoglobin synthesis. In humans and all other monogastric species, B12 is the only bioavailable form of cobalt, since these organisms are unable to synthesize the vitamin from dietary cobalt. Uptake of cobalt from the diet, therefore, must be in the form of vitamin B12 (1), which is also suspected to exacerbate, if not induce, cobalt allergy (2).
