Vitamin B12, scientifically known as cobalamin, is a water-soluble vitamin, like all other B vitamins. This means it can dissolve in water and travel through the bloodstream. The body can store vitamin B12 for up to 4 years, and it can get rid of any excess or unwanted vitamin B12 in the urine.
Vitamin B12 is essential for the health of nerve tissue, brain function, and red blood cells. The major sources of vitamin B12 include meat, eggs, and some yeast products. People with a B12 deficiency may need supplements. Signs of a deficiency include headaches and fatigue. Deficiency or insufficiency can occur when levels of vitamin B12 become too low to meet the demands of the body. This can lead to a number of symptoms and can even progress to irreversible neurological issues if left untreated.
Health benefits
Vitamin B12 is crucial to various bodily processes, including normal functioning of the brain and nervous system, cognitive functioning (ability to think), formation of red blood cells and prevention of anaemia.
It helps the body to create and regulate DNA, and possibly prevents congenital abnormalities. It helps protect the eyes from macular degeneration and is necessary for energy production. Moreover, vitamin B12 is essential for healthy blood. When the body does not have enough B12, it leads to decreased normal red blood cell production (anaemia), which impairs oxygen delivery.
Megaloblastic anemia, also called nutritional-deficiency anaemia, is a type of anaemia caused by B12 or folate deficiency. Megaloblastic anaemia is characterized by impaired DNA synthesis and the formation of large, abnormal, immature red blood cells.
Intake requirements
It is recommended that teenagers over 14 and adults should consume 2.4 micrograms (mcg) of vitamin B12 daily. Pregnant people should consume 2.6 mcg, and lactating people 2.8 mcg. Excessive intake of vitamin B12 has not shown toxic or harmful qualities. However, people should speak with their physician before starting any new supplements.
Some medications may decrease the absorption of vitamin B12 from foods. These medications include: metformin (used to treat diabetes), proton pump inhibitors, H2 receptor agonists often used for peptic ulcer disease.
B12 from foods
Vitamin B12 occurs naturally in many animal products. Good dietary sources of vitamin B12 include beef, pork, ham, poultry, lamb, fish, especially haddock and tuna, dairy products, such as milk, cheese, and yoghurt, some nutritional yeast products and eggs.
Even though vitamin B12 is found in a variety of foods, some people are at an increased risk of developing B12 deficiency or insufficiency. Groups at an increased risk include: older adult, those on restrictive diets like vegetarian diets, people with certain health conditions such as celiac disease.
Deficiency symptoms
Having low or deficient B12 levels can lead to a number of symptoms, some of which can be serious. It can result in irreversible and potentially severe damage, especially to the nervous system and brain. This, however, is uncommon. That said, even slightly lower-than-normal levels of vitamin B12 can trigger symptoms. However, these symptoms are non-specific and are not enough to diagnose vitamin B12 deficiency. Symptoms may include: depression, confusion, memory problems, fatigue, headaches, mood changes and difficulty concentrating. Once symptoms worsen, they can include neurological changes, such as numbness and tingling in the hands and feet. Some people may have difficulty maintaining balance.
Infants who lack vitamin B12 may show unusual movements, such as face tremors, reflex problems, feeding difficulties, irritation and eventual growth problems if left untreated. Deficiency of B12 has been linked to an increased risk of cognitive impairment and depression. Insufficient vitamin B12 can also lead to anaemia. The most common symptoms of anaemia are fatigue, shortness of breath, and an irregular heartbeat. People with anaemia might also experience: a sore mouth or tongue, weight loss, pale or yellowing skin, diarrhea and menstrual problems
Who is at risk?
Several groups of people may be at an increased risk of vitamin B12 deficiency. People with pernicious anaemia may lack vitamin B12. Pernicious anaemia is an autoimmune disease that affects the blood. Patients with this disorder do not have enough intrinsic factor (IF), a protein in the stomach that allows the body to absorb vitamin B12.
Other at-risk groups include people with small intestine problems, for example, an individual with a surgically shortened small intestine. Crohn’s disease is also a risk factor for vitamin B12 deficiency due to frequent involvement of the terminal ileum.
Gastritis, celiac disease, and inflammatory bowel disease (IBD) may lead to a deficiency because these conditions reduce nutrient absorption. People with chronic alcohol use disorder may lack vitamin B12, as their bodies may not absorb nutrients efficiently.
People with diabetes who are treated with metformin should have their B12 levels tested by their healthcare professional regularly. This is because metformin reduces the absorption of vitamin B12.
Treatment for vitamin B12 deficiency
Treatment for vitamin B12 deficiency includes oral vitamin B12 supplements or vitamin B12 injections. Some people have difficulties absorbing vitamin B12 from food sources may need to take supplements.
People can take B12 supplements orally or in a nasal spray. However, oral supplements may not help in many cases of deficiency. In these circumstances, a doctor may recommend vitamin B12 injections.
Vegans and others who do not get enough B12 from their diet can take supplements to avoid deficiency. This is particularly important during pregnancy and while breastfeeding.