Vitamin B12

Vitamin B₁₂ is an important vitamin that helps our bodies use energy from food and keep our nerves and blood healthy. It is one of eight B vitamins and is needed for making DNA, a key part of every cell in our bodies. Vitamin B₁₂ also helps create the protective covering around our nerves and supports the growth of red blood cells, which carry oxygen throughout the body.

Unlike plants, animals need vitamin B₁₂ to stay healthy, but it is made only by certain tiny organisms called archaea and bacteria. We get this vitamin from eating foods like meat, shellfish, liver, fish, poultry, eggs, and dairy products. It can also be found in fortified breakfast cereals and is available as a dietary supplement.

While most healthy adults have enough vitamin B₁₂ stored in their bodies, some groups, like older adults and pregnant women, are more at risk of not getting enough. Not having enough vitamin B₁₂ can cause problems like feeling very tired, changes in sensation, and issues with thinking clearly. It’s especially important for growing children and developing babies, as lack of this vitamin can affect their growth and brain development.

Definition

Vitamin B₁₂ is a special kind of vitamin that helps your body in many important ways. It is made up of a metal called cobalt, surrounded by a ring-shaped molecule. There are different forms of vitamin B₁₂, like cyanocobalamin, hydroxocobalamin, and methylcobalamin, but they all work similarly in your body. Cyanocobalamin is often used in vitamins and foods because it stays stable. Hydroxocobalamin can be used as a treatment for low levels of this vitamin.

Some compounds look like vitamin B₁₂ but don’t work the same way. These are called pseudovitamins. For example, spirulina, a type of algae, contains something called pseudovitamin B₁₂, which doesn’t act like the real vitamin. There are also antivitamins, which can block the real vitamin from working, but these are usually made in labs for special purposes.

Deficiency

Vitamin B₁₂ deficiency can cause serious problems, especially for the brain and nervous system. Even small drops in vitamin B₁₂ levels can lead to tiredness, headaches, feeling dizzy, pale skin, numbness or tingling, trouble with balance, memory issues, and mood changes. It can also weaken the immune system and affect fertility.

One common type of vitamin B₁₂ deficiency is called pernicious anemia. This condition shows three main signs: anemia due to problems with DNA making, digestive issues like diarrhea or constipation, and nerve problems such as loss of sensation or coordination. Children with this deficiency might show delays in development and behavior changes.

People at risk for vitamin B₁₂ deficiency include vegans and vegetarians, older adults, and those who have had certain stomach surgeries. These groups may need supplements to keep their vitamin B₁₂ levels healthy.

Medical uses

Vitamin B₁₂ is used to treat severe vitamin B₁₂ deficiency. This is done by giving injections of the vitamin daily at first, then monthly, or by taking high-dose oral pills.

It can also help in cases of cyanide poisoning. A special form of B₁₂ called hydroxocobalamin can be given intravenously to safely remove the poison from the body. It works by binding to the cyanide, turning it into a harmless compound that is then removed in urine. Sometimes it is used together with sodium thiosulfate.

Dietary recommendations

Most people in the United States and the United Kingdom get enough vitamin B₁₂. However, up to 40% of people in the Western world may have low levels. To help with this, some grain-based foods can be fortified with extra vitamin B₁₂. People who don’t eat animal products, like vegans, should use dietary supplements or fortified foods to make sure they get enough.

Different groups need different amounts of vitamin B₁₂. For example, adults need about 2.4 micrograms each day, while babies need less. Older people, especially those over 50, should get their vitamin B₁₂ from fortified foods or supplements because their bodies may not absorb it well from regular foods. There isn’t a maximum safe amount set for vitamin B₁₂ because high doses haven’t been shown to cause harm in humans.