Warning on vitamin B12 deficiency for vegans and vegetarians

30th December 2021

In the run up to Veganuary leading researchers are warning of the dangers of a quiet epidemic of vitamin B12 deficiency in people who follow increasingly popular plant-based diets.

Plant-based diets (vegetarian or vegan) are becoming significantly more popular as people look to adopt a diet that is seen to be better for the environment, animal welfare, and/or personal health.  Sales of plant-based foods have seen a 49 per cent increase in Western Europe since 2018.

Scientists from around the world with expertise in food, nutrition, medicine, and health have formed a vitamin B12 research discussion group called cluB-12 to raise awareness of B12 deficiency and how it can be addressed. Vitamin B12 is an essential micronutrient which plays a role in supporting red blood cell production, energy, metabolism, and nerve function, but it is not found in plants.

Professor Martin Warren of the Quadram Institute in Norwich, UK, who helped initiate cluB-12, is keen that the public and policymakers are aware of the public health implications and measures needed to mitigate vitamin B12 deficiency.

Vitamin B12 deficiency anaemia can cause a wide range of symptoms. These usually develop gradually but can worsen if the condition goes untreated. Anaemia is where you have fewer red blood cells than normal, or you have an abnormally low amount of a substance called haemoglobin in each red blood cell. 

General symptoms may include: extreme tiredness (fatigue), lack of energy (lethargy), tinnitus, breathlessness, feeling faint, headaches, pale skin, noticeable heartbeats (palpitations), loss of appetite and weight loss. 

Professor Martin Warren said: “There is a hidden epidemic of vitamin B12 deficiency among vegetarian and vegan populations and this is a particular concern for women of child-bearing age. We are concerned that the current UK recommendations, for example, take no account of pregnancy and this urgently needs to be addressed. There are many good reasons to follow a planned and balanced plant-based diet but for a vegan diet especially you should be aware of the potential for nutritional deficiency and the need to take appropriate vitamin B12 supplements.”

Dr Kourosh R Ahmad, co-author from the University of Surrey, said: “Millions of people across the globe are switching to a plant-based diet for a myriad of ethical reasons – whether it’s because they have a love for animals or environmental reasons. Our paper is not about convincing people they are wrong for becoming vegans, but about making sure they are safe and don’t sleepwalk into being B12 deficient. 

“Furthermore, there clearly needs to be a global consensus on guidance on daily intake recommendations for vitamin B12 – not just for adults but specifically for pregnant women and women who want to start a family.” 

Key recommendations for people choosing a vegan or vegetarian diet: 

  • Take a daily supplement containing 4-7 micrograms of vitamin B12 with food 
  • Monitor your vitamin B12 status especially if you have not been taking supplements 
  • Get expert advice to support planning of a plant-based diet, particularly if becoming vegan
  • Get expert advice if you’re on a vegetarian diet and you are a) planning to become vegan, b) planning to become pregnant or are breastfeeding and c) older than 60 

 International recommended nutritional intakes: 

  • UK – recommended nutritional intake (RNI) for vitamin B12 is set at 1.5 micrograms a day for adults and no adjustment is made for pregnancy 
  • USA – the RNI is 2.3 micrograms a day and increases to 2.6 and 2.8 a day for pregnant and breastfeeding women, respectively
  • EU – 4 micrograms a day and increases to 4.5 and 5 for pregnant and breastfeeding women, respectively  

People following a vegan diet are at much higher risk of vitamin B12 deficiency. Estimates suggest deficiency rates as high as 62 per cent in pregnant women. In vegetarians, B12 deficiency is as high as 40 per cent. 

Research undertaken by the Food Databanks National Capability at the Quadram Institute also shows that vegan products in UK supermarkets do not commonly or adequately fortify their vegan food products with vitamin B12

The cluB-12 paper on vitamin B12  deficiency and plant-based diets can be found below:

Notes to editors 

Ali Niklewicz1*, Andrew McCaddon2, Ebba Nexo3, Michelle Murphy4, Helene McNulty5, Mary Ward5, Bruce Wolfenbüttel6, David Smith7, Helga Refsum8, Andrew Klein9, Anne M Molloy10, Jean-Louis Gueant11, Kourosh R Ahmadi1*, Martin Warren12*, Luciana Hannibal13*, P Julian Owen14*, on behalf of cluB-12. *Corresponding Authors.  

  1. Department of Nutritional Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU2 7XH, UK. 
  2. Faculty of Social and Life Sciences, Wrexham Glyndwr University, Wrexham, United Kingdom. 
  3. Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark. 
  4. IISPV, Spain; CIBEROBN, Spain; Unitat de Medicina Preventiva i Salut Pública, Facultat de Medicina i Ciències de La Salut, Universitat Rovira i Virgili, Reus, Spain. 
  5. Nutrition Innovation Centre for Food and Health (NICHE), School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK. 
  6. Professor of Endocrinology & Metabolism, Dept. of Endocrinology, University Medical Center Groningen, HPC AA31, P.O. Box 30001, 9700 RB Groningen, The Netherlands 
  7. OPTIMA, Department of Pharmacology, University of Oxford, Oxford, United Kingdom. 
  8. Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway. 
  9. Department of Anaesthesiology and Perioperative Medicine, Monash University, Melbourne, Victoria, Australia; Department of Anaesthesia and Intensive Care, Royal Papworth Hospital, Cambridge, United Kingdom. 
  10. School of Medicine, Trinity College Dublin, Ireland. 
  11. Department of Hepato-Gastroenterology, University Regional Hospital of Nancy, 545 Vandoeuvre les Nancy. 
  12. Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ. 
  13. Medical Center, Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany 
  14. Consultant Trauma & Orthopaedic Surgeon, Addenbrooke’s Hospital, Cambridge NHS Improvement, Orthopaedics Joint Clinical Lead, East of England, MSK Lead, Cambridgeshire ICS.  

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