Vitamin B12 is important for the way the body works, and people who don't have enough of it may feel tired or have a lack of energyVitamin B12, also known as cobalamin, helps in the production of healthy red blood cells that carry oxygen around the body.Not having enough vitamin B12 is called vitamin B12 deficiency anaemia. This condition makes the body produce larger than normal red blood cells, described as megaloblastic or macrocytic, which don't do their job as well.Once diagnosed, vitamin B12 deficiency can usually be treated successfully with B12 injections and sometimes with B12 tablets.Anaemia and anaemia caused by a lack of vitamin B12 can result in symptoms which include:More specific symptoms linked to a lack of vitamin B12 include:Vitamin B12 deficiency is more common in older people and affects around one in 10 over 75s.The most common cause of vitamin B12 deficiency is pernicious anaemia, an auto-immune condition that affects around one in 10,000 people. Pernicious anaemia is caused by a lack of a protein called intrinsic factor that’s needed to absorb vitamin B12 from food into the body from the gastro-intestinal tract.
This condition is more common in people over 60, in women, in people with a family history of pernicious anaemia or some autoimmune conditions, including Addison’s disease and vitiligo. Vitamin B12 deficiency is risk for people who follow a strict vegan diet who don't eat the major food sources of B12: meat, eggs and dairy products. Babies whose mums are vegetarians may have vitamin B12 deficiency. Other causes of vitamin B12 deficiency include:Blood tests and examination of blood cells under the microscope assess haemoglobin levels, the size of red blood cells and the level of vitamin B12 in the blood. The levels of folate are also usually checked for the related condition folate deficiency anaemia. Once the diagnosis is confirmed, further tests may be carried out to try to find out what's causing the anaemia. A referral may be made to a specialist, such as a haematologist for blood conditions, a gastroenterologist for digestive disorders or a dietitian for advice on eating food containing more vitamin B12.
What harm can having too little of a vitamin do? Consider this: Over the course of two months, a 62-year-old man developed numbness and a “pins and needles” sensation in his hands, had trouble walking, experienced severe joint pain, began turning yellow, and became progressively short of breath. The cause was lack of vitamin B12 in his bloodstream, according to a case report from Harvard-affiliated Massachusetts General Hospital published in The New England Journal of Medicine. It could have been worse—a severe vitamin B12 deficiency can lead to deep depression, paranoia and delusions, memory loss, incontinence, loss of taste and smell, and more. The human body needs vitamin B12 to make red blood cells, nerves, DNA, and carry out other functions. The average adult should get 2.4 micrograms a day. Like most vitamins, B12 can’t be made by the body. Instead, it must be gotten from food or supplements. And therein lies the problem: Some people don’t consume enough vitamin B12 to meet their needs, while others can’t absorb enough, no matter how much they take in.
As a result, vitamin B12 deficiency is relatively common, especially among older people. The National Health and Nutrition Examination Survey estimated that 3.2% of adults over age 50 have a seriously low B12 level, and up to 20% may have a borderline deficiency. There are many causes for vitamin B12 deficiency. Surprisingly, two of them are practices often undertaken to improve health: a vegetarian diet and weight-loss surgery. Plants don’t make vitamin B12. The only foods that deliver it are meat, eggs, poultry, dairy products, and other foods from animals. Strict vegetarians and vegans are at high risk for developing a B12 deficiency if they don’t eat grains that have been fortified with the vitamin or take a vitamin supplement. People who have stomach stapling or other form of weight-loss surgery are also more likely to be low in vitamin B12 because the operation interferes with the body’s ability to extract vitamin B12 from food. Conditions that interfere with food absorption, such celiac or Crohn’s disease, can cause B12 trouble.
So can the use of commonly prescribed heartburn drugs, which reduce acid production in the stomach (acid is needed to absorb vitamin B12). The condition is more likely to occur in older people due to the cutback in stomach acid production that often occurs with aging. Vitamin B12 deficiency can be slow to develop, causing symptoms to appear gradually and intensify over time. It can also come on relatively quickly. Given the array of symptoms it can cause, the condition can be overlooked or confused with something else. While an experienced physician may be able to detect a vitamin B12 deficiency with a good interview and physical exam, a blood test is needed to confirm the condition. Early detection and treatment is important. “If left untreated, the deficiency can cause severe neurologic problems and blood diseases,” says Dr. Bruce Bistrian, chief of clinical nutrition at Harvard-affiliated Beth Israel Deaconess Medical Center. It’s a good idea to ask your doctor about having your B12 level checked if you:
A serious vitamin B12 deficiency can be corrected two ways: weekly shots of vitamin B12 or daily high-dose B12 pills. A mild B12 deficiency can be corrected with a standard multivitamin. In many people, a vitamin B12 deficiency can be prevented. If you are a strict vegetarian or vegan, it’s important to eat breads, cereals, or other grains that have been fortified with vitamin B12, or take a daily supplement. A standard multivitamin delivers 6 micrograms, more than enough to cover the average body’s daily need. If you are over age 50, the Institute of Medicine recommends that you get extra B12 from a supplement, since you may not be able to absorb enough of the vitamin through foods. A standard multivitamin should do the trick. The Internet is full of articles lauding the use of vitamin B12 to prevent Alzheimer’s disease, heart disease, and other chronic conditions or reverse infertility, fatigue, eczema, and a long list of other health problems. Most are based on poor or faulty evidence.