What is Vitamin B12?
Key Takeaways
Vitamin B12, also known as cobalamin, is an essential nutrient.
Vitamin B12 is needed for DNA and RNA synthesis, nervous system function, and the production of blood cells by the bone marrow.
Vitamin B12 is also involved in the metabolism of homocysteine. Vitamin B12 deficiency can lead to high homocysteine levels, which are associated with increased cardiovascular disease risk. Most animal-based foods contain vitamin B12, including meat, fish, eggs, and dairy products.
Very few plant-based foods naturally contain vitamin B12, so people following a strict plant-based diet may be at risk for vitamin B12 deficiency.
Either oral or injectable vitamin B12 supplements are available and may be recommended for those whose levels of this vitamin are low or who are at a greater risk of deficiency.
What is Vitamin B12?
Vitamin B12, also known as cobalamin, is an essential nutrient that’s needed for several important bodily functions, including DNA and RNA synthesis, nervous system function, and the production of blood cells by the bone marrow. This article will discuss how vitamin B12 works in the body, how to know if you’re not getting enough, and what to do about it.
Functions of Vitamin B12 in the Body
Vitamin B12 plays several key roles in the body.
DNA and RNA synthesis. Vitamin B12 plays a critical role in DNA and RNA synthesis, which is important in the functioning of our body systems.
Nervous system function. Vitamin B12 is important for maintaining the myelin sheath around our nerves. This is a fatty coating around nerve cells, which acts as an insulator and allows the nervous system to transmit signals efficiently. Because of this, vitamin B12 is crucial for the proper functioning of the brain and nerves.
Blood cell production. Vitamin B12 is also important for the processes of cell division and the production of blood cells in our bone marrow. Because of this, it’s needed to produce red blood cells (RBCs), as well as white blood cells (WBCs) and platelets. These are cells that need to be continually produced for our body’s daily function.
Homocysteine and Vitamin B12
Homocysteine is an intermediary amino acid. The body uses homocysteine to create other amino acids, which are then used as building blocks for proteins. Homocysteine is naturally formed in the body when old proteins are broken down.
High homocysteine levels have been associated with a higher risk for a number of serious medical conditions, including cardiovascular disease, such as ischaemic heart disease and ischaemic stroke.
Vitamin B12 is for the metabolism of homocysteine. Without enough vitamin B12, homocysteine can build up in the bloodstream, leading to high levels. This is a major reason why vitamin B12 is essential to healthy aging and longevity.
Recommended Daily Intake
Vitamin B12 is an essential nutrient. For adults, the US National Institutes of Health recommends the following daily intakes of vitamin B12:
Men: 2.4 mcg
Women who are not pregnant or nursing: 2.4 mcg
Women who are pregnant: 2.6 mcg
Women who are nursing: 2.8 mcg
Sources of Vitamin B12
Most people are able to obtain enough vitamin B12 from the foods that they eat. This nutrient is found in virtually all animal-based foods, including meat, fish, eggs, and dairy products. There are very few natural plant-based sources of vitamin B12, although some plant-based products are fortified (meaning that vitamin B12 is added to them), including many cereals, plant-based milks, and soy products.
Some people take oral supplements of vitamin B12. These may be useful for some people, especially those who stick to a plant-based diet or those who have low vitamin B12 levels. The most common forms of the vitamin found in supplements are cyanocobalamin and methylcobalamin. Some research has shown that cyanocobalamin may be slightly better absorbed than methylcobalamin, but in general, either type is effective at treating B12 deficiency.
There is also an injectable form of vitamin B12. This treatment is usually used for people who have severe issues with absorbing vitamin B12 from the intestine, and it may also be used for those who have a severe B12 deficiency.
Although it’s important to get enough vitamin B12, there may also be a risk of getting too much. Some studies have shown that having elevated levels of vitamin B12 increases the overall risk of mortality, especially in older people. It’s also been associated with a higher risk for anxiety and glaucoma. If you consume vitamin B12 supplements, don’t exceed the safe limits listed on the bottle or the dose prescribed by your doctor.
Multivitamins generally contain vitamin B12 along with other essential vitamins and minerals. The exact dose varies according to the specific product, so you’ll need to check the bottle to find the dose of vitamin B12 in a particular multivitamin. If your multivitamin already contains vitamin B12, then adding a B12 supplement to this could cause you to get too much of this vitamin, so it’s important to check.
Vitamin B12 Deficiency
Causes
A deficiency of vitamin B12 can have a few different causes:
Diet. If a person isn’t consuming enough vitamin B12, they will eventually develop a deficiency. Because vitamin B12 is primarily found in animal products, this usually occurs in vegans or strict vegetarians who avoid animal products or consume them in very limited amounts.
Pernicious anemia. This is caused by a lack of a protein called intrinsic factor, which is produced by certain cells in the stomach. Intrinsic factor is required for vitamin B12 to be absorbed in the intestines. Without enough intrinsic factor, vitamin B12 can’t be absorbed, and deficiency will develop. Pernicious anemia can be caused by autoimmune conditions causing antibodies to attack these stomach cells.,
Gastrectomy/bariatric surgery and gastritis. Surgical removal of the stomach and gastritis affects the liberation of vitamin B12 from food proteins, and reduced absorption of vitamin B12 due to decreased intrinsic factor production.
Gastrointestinal conditions affecting absorption in the small intestines. Medical conditions that affect the small intestines, such as pancreatic dysfunction, which produces enzymes involved in the absorption of Vitamin B12, small intestine inflammation from inflammatory bowel disease, or surgery removing parts of the small intestines, can all affect the absorption of Vitamin B12 from food.
Testing and Monitoring Vitamin B12 Levels
To check for a possible deficiency, vitamin B12 levels are usually measured through a blood test called the serum B12 test.
Your doctor may order a vitamin B12 test if they suspect that you have a deficiency of this vitamin. People who may benefit from this testing include:
Strict vegetarians or vegans
Those who are taking metformin (a common diabetes medication which can reduce absorption of vitamin B12) or other medications that can affect B12 levels
Those who have had certain surgical procedures (like gastric bypass surgery)
Those with chronic conditions of the digestive system
Those having symptoms and signs that may indicate a vitamin B12 deficiency
If you’re diagnosed with a vitamin B12 deficiency, then your doctor will most likely prescribe either oral or injectable B12. After taking B12 for a few months, your levels will be checked again, so your treatment can be adjusted if necessary.
Vitamin B12 as part of a healthy lifestyle
Vitamin B12 is a crucial nutrient. It helps to ensure that you have enough energy to get through your day feeling good, and it also helps to protect the long-term health of your brain and heart. To live a long and healthy life, it’s essential to ensure that you’re getting enough vitamin B12.
Vitamin B12 works together with other nutrients to keep you healthy. For example, vitamin B9 (folic acid) is also important for red blood cell production, and vitamin B6 (pyridoxine) is also important for breaking down homocysteine. For optimal health and wellness, it’s important to ensure that you’re getting balanced amounts of all of the essential vitamins and minerals.
Our NOVI Assessment Max clients receive comprehensive testing for a variety of nutrients, including vitamin B12. This gives you actionable information that you can use to help improve your well-being. The program includes consultations with healthcare practitioners, to help you develop a personalized plan that supports your long-term health and longevity.