Are you getting enough vitamin B12?

Author: ANCP   Date Posted:11 August 2015 

Do you know whether you’re getting enough Vitamin B12? Many older people and vegetarians are at risk of becoming deficient in this essential vitamin, which is required for healthy blood and nerve function.

Functions of Vitamin B12: Vitamin B12 is required for the healthy functioning of every cell in the body. Some of its most important roles include:

  • The production of healthy red blood cells and DNA.
  • Aiding the production of nerve cells and the myelin sheath that lines the nerves.
  • Along with Folic Acid and vitamin B6, Vitamin B12 is required for the metabolism of a compound called homocysteine, a marker of inflammation in the body. High levels of homocysteine in the blood may be associated with poor cardiovascular health.
  • Supporting healthy immunity.

Symptoms of Vitamin B12 deficiency:

The symptoms of Vitamin B12 deficiency predominantly affect the blood, the nervous system (which encompasses both the nerves and the brain), and the gastrointestinal tract.

  • Blood: Vitamin B12 deficiency can be a form of anaemia, and the symptoms it causes are similar to those observed in iron deficiency or folic acid deficiency. These may include fatigue, pale skin, shortness of breath (especially with physical exertion) and heart palpitations.
  • Nervous system: Vitamin B12 may cause a range of symptoms associated with impaired nerve function, including disturbances in motor skills, eyesight and the control of the bowel and bladder. Cognitive and psychological effects may include mood changes and memory problems. Research suggests that these symptoms may occur even when your levels are only slightly lower than normal, and before the deficiency is severe enough to cause the anaemia symptoms referred to above.
  • Gastrointestinal System: Symptoms of Vitamin B12 defiency that may affect the digestive tract include glossitis (a swollen, reddened tongue), reduced appetite, weight loss, abdominal pain and intermittent disturbances in bowel habits.

Diagnosing Vitamin B12 deficiency:

Diagnosis of Vitamin B12 deficiency isn’t always easy, even with blood tests, so it’s important that you consult your doctor if you suspect you may be deficient in this important nutrient. Your doctor may need to arrange for several different types of testing to be done in order to confirm your Vitamin B12 status.

The results of those tests will reflect a combination of your current intake and stored Vitamin B12. Since it can be stored in the liver for many years, by the time a deficiency is detected in your blood stream it is likely your intake and/or absorption have been inadequate for quite a substantial period – perhaps even five to ten years.

Vitamin B12 and older people:

It has been estimated that up to 43% of older people could be deficient in Vitamin B12. A combination of different factors can contribute to this issue:

  • As we get older, our ability to digest Vitamin B12 declines, often due to reduced gastric acidity and/or chronic inflammation of the stomach lining (sometimes referred to as atrophic gastritis, an issue that may affect up to 30% of older Australians)
  • Many people eat less nutritious diets as they get older, which may reduce their intake of Vitamin B12.
  • Older people are more likely to take pharmaceutical medicines, some of which may further compromise Vitamin B12 status


Vitamin B12 and Vegetarians:

Humans obtain almost all their Vitamin B12 from animal products, with the majority coming from red meat and dairy products. Vegetarian sources are extremely rare, but it is produced by some algae and may also be present in some seaweeds such as nori.

Consequently, vegans are particularly prone to Vitamin B12 deficiency and need to maintain their intake via supplementation. Vegetarians who consume dairy products and eggs are at less risk but still need to take appropriate care to ensure they don’t become deficient.

Who else is at risk of vitamin B12 deficiency?

Vitamin B12 deficiency is sometimes caused by a condition called pernicious anaemia, in which Vitamin B12 is unable to be absorbed. Vitamin B12 levels may also be negatively impacted by:

  • Excessive alcohol consumption.
  • The use of certain pharmaceutical medicines.
  • Conditions associated with chronic diarrhoea, such as Coeliac disease and irritable bowel syndrome.

How much Vitamin B12 do I need?

The recommended dietary intake of Vitamin B12 for adults is 2.4 mcg per day. However, many older people are likely to have compromised ability to absorb Vitamin B12, and may require a higher intake, often from supplements. It has been estimated that elderly people may require as much as 1032 mcg Vitamin B12 per day in order to reverse deficiency states.