B12 Protocol

Vitamin B12 deficiency guideline CSS Authored by May Selvakumar Practice Nurse May 2020

This guideline is for the management of vitamin B12 deficiency in primary care for people aged 16 years and onwards. In pregnancy seek advice from secondary care.

Signs and symptoms of Vitamin B12 deficiency anaemia

  • Cognitive changes
  • Dyspnoea
  • Headache
  • Indigestion
  • Loss of appetite
  • Palpitations
  • Tachnypnoea
  • Visual disturbance
  • Lethargy and fatigue
  • Angina (in older people)
  • Tachycardia
  • Weight loss
  • Episodic diarrhoea
  • Pale skin

Neurological complications associated with Vitamin B12 deficiency

  • Loss of mental and physical drive
  • Muscle weakness
  • Vision loss
  • Psychiatric disturbances (ranging from mild neurosis to severe dementia)
  • Urinary or faecal incontinence
  • Symmetrical neuropathy affecting legs more than the arms (this usually presents with ataxia or paraesthesia)


  • FBC
  • B12
  • Folate
  • Intrinsic factor antibodies (only needed once)
  • Coeliac screen (Anti-TTG antibodies) (only needed once)

Why do we need it?

Vitamin B12 is needed for healthy red blood cells to prevent a type of anaemia called megaloblastic anaemia. IT is also important for maintaining a healthy nervous system.

How much do I need?

Over the age of 15 years, males and females need 1.5 micrograms per day (Government Dietary Recommendations from the Department of Health, Public Health England, 2016).

Where are the best sources found?

Vitamin B12 are naturally present in animal food products but can be added to other food during manufacturing process. Several food sources of vitamin B12 are listed below.

What if I don’t eat these foods?

Vegetarians and vegans are at risk of having a low vitamin b12 intake. Both the Vegan Society and Vegetarian Society recommend that people who do not eat animal products should aim to have 3 μg of B12 a day. In addition, they recommend that they should include B12 fortified foods or supplements as a regular part of their daily diet to achieve the recommended intake.




  1. Anaemia – B12 and folate deficiency – NICE – https://cks.nice.org.uk/anaemia-b12-and-folate-deficiency#!prescribingInfo
  2. Iron and Vit B12 leaflet 26 04 2010 final pdf (Practice shared drive\Practice\Patient Info\Vitamins)
  3. Management of Vitamin B12 Deficiency in Primary Care – Worcestershire Area Prescribing Committee – https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwirrK_zgNnpAhXElFwKHcQbBzkQFjAAegQIAxAB&url=http%3A%2F%2Fwww.southworcsccg.nhs.uk%2FEasysiteWeb%2Fgetresource.axd%3FAssetID%3D180298%26type%3Dfull%26servicetype%3DAttachment&usg=AOvVaw3Jy5NObpeyQMSuGVJSzMCT
  4. Vitamin B12 and Health – Leicestershire Nutrition and Dietetic Services – https://www.lnds.nhs.uk/Library/Vitamin_B12_and_HealthOct2018LNDS123.pdf