Cobalt is essential for humans because it is a part of vitamin B-12. This form of cobalt is obtainable from micro-organisms or from animal sources. Vegetable sources of cobalt are more important to animals that are ruminants (sheep and cattle). Cobalt deficiency in humans is like vitamin B-12 deficiency, with anaemiaFind out more about this term and nervous system problems. As little as 0.1 microgram cobalt as vitamin B-12 per day is needed by adults. Total cobalt intake may be in a range from 10 to 1800 micrograms per day. Cobalt in a different chemical form (i.e. not as part of vitamin B-12) will stimulate blood formation, but this is probably not a normal action. When cobalt was used to stabilize beer froth, it was found to have a toxic effect on the heart. Its toxicity, at cobalt intakes of about 8000 micrograms per day, probably arose from its interaction with alcohol itself, and other nutritional problems created by alcohol.