Vitamin B12 Deficiency and Dementia


Vitamin B12 Deficiency and Dementia

Vitamin B12 deficiency and dementia: can B12 deficiency increase the risk of dementia? Can the use of B12 as an adjuvant therapy help fight dementia?

Guest Post: Dementia and Micronutrients

Dementia-related diseases are often associated with low micronutrient levels, as elderly people often eat an unbalanced diet and are more likely to suffer from malabsorption, limiting their intake of essential nutrients. So, what exactly is the relationship between dementia and micronutrients – in particular, vitamin B12? Moreover, how might the benefits of a vitamin B12 intake help prevent and even treat dementia?

To help answer these questions we have invited expert Dr Birgit Schiel to guest write this article. 

Malnutrition Leads to Cognitive Deficits

Studies show that mental performance is supported by sufficient levels of micronutrients. However, as dietary behaviours change with age and the body’s absorption mechanisms deteriorate, elderly people increasingly suffer from malabsorption, which makes it harder to obtain a sufficient supply of micronutrients. 

Oxidative Stress as a Factor in Neurodegeneration

Micronutrients help protect nerve cells from oxidative damage and can counteract oxidative processes like atherosclerotic pathological changes, thus improving microcirculation in the brain. They also improve the metabolism of homocysteine, reducing inflammation. 

Using Micronutrients to Prevent Dementia

The following nutrients are particularly important for preserving mental dexterity:

  • B vitamins (i.e. folic acid, vitamin B12) improve cell energy metabolism and blood circulation to the brain

  • Omega 3 fatty acids (particularly docosahexaenoic acid – DHA) plays an important role in the functionality of the central nervous system (CNS)

  • Coenzyme Q10 can help protect against damage to brain cells and aids the stabilisation of cell membranes

  • Acetylcarnitine promotes the release of acetylcholine, is neuroprotective and may improve brain function

  • Zinc is important to prevent the loss of brain cells. Patients suffering from dementia often have reduced zinc levels

  • Ginkgo allows for better blood circulation to the brain and improved memory performance

B12 Deficiency Increases the Risk of Dementia

Vitamin B12 deficiency can encourage cognitive decline in older age – this fact was published in Neurology (2011) after studies took place (1). The results of these studies indicated that a lack of B12, which is essential for proper neuronal functioning, should be regarded as a potential risk factor in the development of dementia and related diseases.

B Complex to Prevent Cognitive Decline

Methylation factors such as folic acid, vitamin B12 and vitamin B6 can help prevent the atrophy of grey matter, thus preventing cognitive decline. This was discovered by a study at Oxford University, in which 156 patients with mild cognitive deficits took part. Each patient was given a vitamin B complex containing 800 mcg folic acid, 20 mg vitamin B6 and 500 mcg vitamin B12. The study demonstrated that relatively simple intervention could reduce the loss of specific neurons in the medial temporal lobe (2).

Methylcobalamin – Active Vitamin B12

Methylcobalamin is a specific form of vitamin B12, which is particularly important for cell growth in the CNS. Cyanocobalamin must first be metabolised in the liver into one of the active forms (5 desoxyadenosylcobalamin or methylcobalamin) before it is biologically available. However, this requires a good functioning liver. The neuroprotective properties of methylcobalamin can be explained through vitamin B12’s neuronal regenerative qualities and through folic acid’s homocysteine ​​reducing abilities.

Further reading: Vitamin B12 Forms and Methylcobalamin 

Vitamin B12 and Dementia: Conclusion

In the active form of methylcobalamin, vitamin B12 offers a valid option for the prevention and treatment of dementia. Regular monitoring of B12 levels through vitamin B12 tests, as well as associated parameters (homocysteine, folic acid and vitamin B6) may help identify deficiencies in good time.

About the Author:

Birgit SchielDr Birgit Schiel

Life and social coach (focusing on health advice)
Individual diploma degree Health Sciences – Specialist subject: Pharmacy
Doctor of Natural Sciences

Scientific advisory activity at Pro Medico



  1. Vitamin B12, cognition, and brain MRI measures: a cross-sectional examination
  2. Preventing Alzheimer’s disease-related grey matter atrophy by B-vitamin treatment