Vitamin B12

What is Vitamin B12?

Vitamin B₁₂, also known as cobalamin, is a water soluble vitamin containing cobalt in its structure. Like folic acid, vitamin B₁₂ deficiency also causes anemia. It is an essential micronutrient found in several foods such as meat, fish, and dairy products. B₁₂ is an essential vitamin that controls nerve tissue, brain function, and red blood cell production. It is the first natural product that contains cobalt atom in its structure.

The elemental analysis gives the various structures of vitamin B₁₂ but the structure which is now accepted requires a formula of C₆₃H₈₈CoN₁₄O₁₄P.

Vitamin B₁₂ Structure

It has been obtained as a red crystalline solid that dissolves in water to give red solutions. It is a coordination complex of cobalt. The cobalt atom in vitamin B₁₂ is placed on the center of a corrin ligand which is further bound by a benzimidazole ligand and adenosyl group given above the picture.

The different values of molecular weight are obtained by the ebullioscopic and X-ray methods. Therefore, vitamin B₁₂ is the collection of chemical compounds which are different molecular weights. All these chemical compounds are similar structures and show vitamin activity in the biological system.

• In cyanocobalamin, the adenosyl ligand is replaced by the cyanide group.
• In hydroxocobalamin, the adenosyl ligand is replaced by the hydroxide group.
• In methylcobalamin, the adenosyl ligand is replaced by the methyl group.

The hydrolysis of vitamin B₁₂ or cyanocobalamin with hydrochloric acid under different conditions produces ammonia, 1-aminopropyl-2-ol, 5,6-dimethyl benzimidazole, 5,6-dimethylbenzimidazole-1-α-D-ribofuranoside, and 3-phosphate of 5,6-dimethylbenzimidazole-1-α-D-ribofuranoside.

Source of Vitamin B₁₂

Like other B vitamins, it is an essential nutrient that cannot be produced in our bodies. Therefore, we need to get vitamin B₁₂ from external sources like diet or supplements. Animal products such as meat and dairy products are the main sources of vitamin B₁₂.

Like folic acid, the deficiency also causes anemia. It can be easily treated by supplements or food sources that contain high levels of vitamin B₁₂. The food sources which contain a huge amount of B₁₂ are,

• Beef, liver, and chicken
• Fish and shellfish like trout, salmon, tuna fish, and clams
• Milk and dairy products like yogurt, and cheese
• Eggs
• Fortified cereal
• Fortified nutritional yeast

Deficiency

Most people in the United States and other well-developed countries get enough B₁₂ in their daily nutrients. Vitamin B₁₂ deficiency can occur in two ways,

• When people do not get enough B₁₂ in their daily nutrients.
• When our body does not absorb or store this nutrient.

The most common symptoms shown due to B₁₂ deficiency are,

• Feeling tired and weak causes difficulty walking.
• Mania and psychosis cause depression
• Poor memory, poor reflexes, and confusion.
• Breathlessness.
• Headaches.
• Pale skin.

It is an important B vitamin that serves a crucial role in nerve tissue health, brain function, and the production of red blood cells.

It is an essential nutrient for healthy blood. The deficiency of vitamin B₁₂ leads to decreased normal red blood cells or causes iron deficiency anemia. Megaloblastic anemia or nutritional deficiency anemia is also caused by the deficiency of B₁₂ or folate which affects our blood oxygen levels.

Functions of Vitamin B₁₂

Vitamin B₁₂ functions or controls several biological processes in our body. The main functions of B₁₂ are,

• It functions on red blood cell production to prevent anemia.
• It functions on the brain and nervous system of our body to increase cognition or thinking power.
• It helps to create or regulate deoxyribonucleic acid (DNA).
• It helps to protect our eyes from macular degeneration.
• Like other vitamins, vitamin B₁₂ is also useful for energy production in biological systems.

Intake Requirements

• According to the National Institutes of Health (NIH), vitamin B₁₂ for women and men ages 14 and up is 2.4 micrograms (mcg) per day.
• For pregnant or breastfeeding women the daily requirement of B₁₂ increases. Therefore, pregnant women should need 2.6 mcg per day during pregnancy, and for breastfeeding women, it should be 2.8 mcg per day.
• Excessive intake of B₁₂ does not cause any toxic or harmful effects on our bodies.

Older people have a high risk for deficiency of B₁₂ because they are unable to absorb B₁₂ from naturally occurring foods.  A high risk of vitamin B₁₂ deficiency for vegetarians comes due to their diet excluding food products that come from animal sources.