What Causes a Vitamin B12 Deficiency?

Reasons for a B12 Deficiency 

What Causes a Vitamin B12 Deficiency?

The causes of a vitamin B12 deficiency explained. Vegan / vegetarian diet, malabsorption, stress and other reasons for a B12 deficiency.

Reasons for a Vitamin B12 Deficiency

The causes of a vitamin B12 deficiency can be categorized three ways:

Lack of Vitamin B12 Intake/Nutrition

Here, a lack of B12 is caused by insufficient intake through the diet. This is usually the case for vegans and vegetarians, but can also occur in those who eat an unbalanced diet.

Increased Need for Vitamin B12

More vitamin B12 is required than is provided through the diet, even when this is a good amount. This is sometimes the case when experiencing sudden crises or periods of increased stress.

Malabsorption of Vitamin B12

In this case, the body simply cannot absorb and subsequently utilize enough vitamin B12, even though vitamin B12 levels are being sufficiently covered by nutrition. This so-called malabsorption is particularly common amongst the elderly. Even minor disorders of the stomach and intestine can lead to usage difficulties for the body. Additional causes of malabsorption include alcohol and many types of medication.

Who is at Risk of a Vitamin B12 Deficiency?

Vitamin B12 deficiencies are most typically found amongst the following types of people or circumstances:

  • Vegans
  • Vegetarians
  • Unbalanced diet
  • Pregnancy/ breastfeeding
  • In crises
  • In stress
  • HIV infection
  • Elderly people
  • Damage to/inflammation of the stomach and intestine
  • Gastritis
  • Crohn’s disease
  • Helicobacter pylori infection
  • Alcoholism
  • When taking certain drugs and medication
  • Heavy smokers
  • Tapeworm
  • Liver damage, pancreatic damage

The Causes in Detail

The following section will discuss deficiencies and their causes in more detail, with practical examples where possible.

1. B12 Deficiency and the Diet

Vitamin B12 is relatively difficult to obtain and is generally only sourced in significant amounts from animal products. It is sometimes found in traces in plant foods, but the quantities in these cases would not be sufficient to fulfil the body’s daily B12 needs.

Vitamin B12 is predominantly found in offal and organ meats, but such foods are less commonly consumed in the modern day. Additionally, it is important to note that vitamin B12 is heat sensitive, so cooking B12 rich foods significantly lowers its content. Thus even omnivores do not necessarily obtain sufficient amounts of B12 through the diet.

2. An Increased Need for Vitamin B12

In times of crises and stress there in an increased need for vitamin B12. Examples of such circumstances include extreme physical and mental pressures, psychologically and mentally stressful situations, experiencing strong and heavily impacting emotions such as fear, anxiety, sadness and heartache and when experiencing emotional processes as a part of spiritual or therapeutic practices. If the immune system is overworked as a result of battling a disease, then an increase in vitamin B12 levels will also be required.

The increased need is partially due to the temporary disturbances that such circumstances cause. Stress results in decreased blood flow to organs and the digestive system, whilst also upsetting the balance in stomach acid and enzymes. Vitamin B12 is required in great quantities for the production of hormones and neurotransmitters. In stressful situations hormones like adrenaline, noradrenaline and serotonin are released in large quantities, which in turn uses up B12 supplies significantly. Periods of prolonged stress can therefore cause deficiency, but ordinarily it is possible to cover the body’s daily requirement through the diet.

3. Vitamin B12 Malabsorption

When absorption is impaired, the body is unable to utilize the vitamin B12 that passes through, leaving it to be simply excreted unused.

There are two opportunities for vitamin B12 to be absorbed in the body:

1. Via the oral mucosa

2. Via the ileum: the final section of the small intestine

The majority is absorbed via the small intestine, however, even the most minor disturbance due to inflammation or any other reason can significantly affect absorption capabilities. In addition, sufficient levels of the glycoprotein intrinsic factor are required to assist absorption. If there is not enough IF then only minimal quantities of B12 can be absorbed via passive diffusion. For these reasons gastrointestinal inflammations are a common deficiency cause. Such problems tend to arise from poor dietary habits frequently found in industrialized countries, which is why a deficiency can also be encountered despite sufficient intake.

Chronic gastrointestinal disorders such as Crohn’s disease severely impede absorption, so those affected usually require high dosage supplements throughout treatment to prevent a B12 shortage. Similarly, liver and pancreatic diseases as well as those who have had part of their stomach or intestine removed often also need to supplement their diet long term using high doses of B12.

Alcoholism and heavy smoking can damage the gastric and intestinal walls and disturb the metabolism, which commonly results in a vitamin B12 deficiency.

A number of drugs, including contraceptive pills, diabetic, heartburn and anti-rheumatism medication can interfere with absorption and so is another potential reason for a deficiency to arise.

Vitamin B12 Deficiencies and Medication

A number of drugs are known to significantly hinder vitamin B12 absorption, which is why some patients often also incur a vitamin B12 deficiency. Interactions can also occur with other substances and drugs. A list of some of these can be found in the table below.

  • Alcohol and drugs
  • Heavy smoking
  • High coffee intake
  • High doses of vitamin C
  • High sugar intake
  • Consumption of food that is too hot (stomach and intestinal irritation)
  • High absorption of synthetic vitamin B12
  • Taking of acid blockers/ulcer medication
  • Taking of diabetes medication
  • various other medication (antibiotics, psychotropic drugs, aspirin, chemotherapy, oestrogen-based contraceptives and hormone drugs (proton pump inhibitors), diabetes medication (metformin), antihypertensive drugs (ACE), medication for heart problems (betablockers, nitrate sprays, nitroglycerin), cholesterol lowering medication (statins), impotence medication

Vitamin B12 Deficiency Causes Chart

The following diagram follows the metabolism of vitamin B12 and at which points a deficiency may be triggered.

 B12 Deficiency Diagram




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