Vitamin B12 deficiency can cause brain and nervous system damage.

Vitamin B12 deficiency signs, symptoms:

• anemia
• fatigue
• weakness
• constipation
• weight loss
• loss of appetite
• depression

Usually deficiency treatment includes cyanocobalamin injections.

Recommended Dietary Allowances (RDA) for Vitamin B12:

• children 1-3 years 0.9 mg per day
• children 4-8 years 1.2 mg per day
• children 9-13 years 1.8 mg per day
• 14-18 years 2.4 mg per day
• 14-18 years pregnant 2.6 mg per day
• 14-18 years lactating 2.8 mg per day
• adult 2.4 mg per day
• adult pregnant 2.4 mg per day
• adult lactating 2.4 mg per day

Vitamin B12 is naturally found in foods of animal:

• meat
• liver
• shellfish
• milk
• eggs

• Mollusks
• Liver
• Fortified breakfast cereal
• Trout
• Salmon
• Beef
• Yogurt
• Haddock
• Clams
• Tuna
• Pork
• Chicken

It also exists in brewer's yeast.

Vitamin B12 is water-soluble and not toxic in big doses.

Vitamin B12 (B-12) term can be defined in two ways. Formally Vitamin B12 is collection of calamines - cobalt and corrin ring molecules.
In the narrow sense Vitamin B12 means Cyanocobalamin - one of calamines.

Vitamin B12 plays role in following processes:

• brain functioning
• nervous system functioning
• formation of blood

It was isolated from liver by Karl A. Folkers in 1948. Vitamin B-12 was first synthesised by Robert Burns Woodward in 1973.