Missing consensus on B12 deficiency amid skyrocketing plant-based diets, flag researchers

04 Jan 2022 --- With more than half a million global consumers set to participate in Veganuary, UK researchers are warning of a “quiet epidemic” of vitamin B12 deficiency, which is common in people following plant-based diets. As a result, the researchers are calling for a global consensus on recommended daily intake (RDA) guidance.

“For people on vegetarian and especially vegan diets, it is important that they either take some extra B12 in the form of a supplement or take a food that has been fortified with the nutrient,” professor Martin Warren of the Quadram Institute tells NutritionInsight. 

Notably in vegetarians, deficiency is as high as 40%. For pregnant women, this rises to 62%. However, many consumers can face difficulties in finding good dietary sources. 

Warren notes some varieties of algae like chlorella have quite good levels of B12. Similarly, UK supermarket Sainsbury’s was selling mushrooms that also contained B12.

“However, this is a confusing area – other foods such as spirulina (a cyanobacterium) make the wrong type of B12 and cannot be used even though it is often highlighted as a good source of the nutrient,” he continues.Vitamin B12 plays a role in supporting red blood cell production, energy, metabolism and nerve function, but it is not found in plants.

Lacking clinical interest
Hoping to bring attention to B12 deficiency, Warren teamed up with other medics to create cluB-12 a couple of years ago. 

“We felt there was a lack of clinical interest in B12 – it falls between two specialties – hematology and neurology.”

Therefore, the research discussion group is highlighting that the public and policymakers should be aware of the public health implications and measures needed to mitigate vitamin B12 deficiency.

“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,” adds Dr. Kourosh Ahmad of the University of Surrey. 

Creating a consensus 
Overall, the experts’ key recommendations for people following vegan or vegetarian diets are: 

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

Warren also points out that while there are general agreements on the importance of B12 – different countries have different views on what level is important. 

Generally, B12 deficiency is defined as when the serum/plasma B12 levels drop below 148 pmol/L (200 pg/mL) or 150 pmol/L (203 pg/mL), according to WHO and the US Institute of Medicine.

“However, just as with cardiovascular disease risk factors, it is now recognized that there is no sharp cutoff for identifying harmful B12 status but that there is a continuous inverse relationship between serum B12 and a variety of undesirable outcomes.”Current UK recommendations take no account of pregnancy, which the researchers say “urgently” needs to be addressed.

Issues with tests
This lack of a cutoff is why the use of B12 tests has limited meaning – there is a lot of variability, he continues. 

“Many people use these values in a very strict manner – for example, a level of 147 pmol/L would be deficient, but a level of 149 pmol/L would be fine. Clearly, there can be no such distinction.”

However, CluB-12 and other industry experts are developing simple home test kits for B12 along the lines of a lateral flow test to help identify people who may be at risk.

In light of rising awareness, other researchers created a calculator that may improve the biomanufacturing of vitamin B12. 

Spotlight on supplementation
Honing in on the specifics of supplementation, Warren says he is currently not aware of taking too much B12 being an issue. However, some nutrient shops sell huge quantities of the vitamin – around 500 times the RDA in a single tablet. This may have other effects on the microbiome, but this has not been established. 

“Most people require only a few micrograms of B12 from their diet – so taking a tablet with 10 μg micrograms, for example, is plenty – but it should be taken with food.”

It is also of crucial importance to make people aware of the importance of B12 – especially those on vegetarian and vegan diets. 

“Most people do not know their B12 level. As many of the symptoms are quite general (tiredness, brain fog, muscle weakness) and build up over many months – it often is not recognized,” says Warren. 

“There is a need to improve the level of information provided to medics during their training – and keeping GPs and clinics up to date with developments and latest tests. We should look to provide more information on vegan food in particular to highlight whether there is adequate B12 included within the recipe,” he concludes. 

Unilever is also spotlighting vitamin deficiencies common in vegans, noting that public health strategies could play a key role. 

Other Veganuary highlights include plant-based cheese launches and a Barry Callebaut study examining attitudes around chocolate. 

By Katherine Durrell