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Many vegans and vegetarians lack vitamin B12

- and do not have a clue

Many vegans and vegetarians lack vitamin B12Global heating and the whole climate debate have greatly increased the number of vegans and vegetarians. Their intensions may be good, but what they do not know is that their lifestyle can lead to serious health problems. A Spanish study of vegetarians and vegans has shown that 11% of the study participants had subclinical or clinical vitamin B12 deficiency. Earlier studies supporting this finding. Because the problem is insidious, it is often difficult to see the link between the deficiency and the symptoms caused by anemia or disturbances in the nervous system. The lack of vitamin B12 may also increase the risk of impaired fertility and development disturbances in the fetus. It is therefore a good idea for vegans and vegetarians to take a vitamin B12 supplement.

Vitamin B12 is only found in animal sources like meat, fish, eggs, and dairy products. We humans absorb the vitamin in the small intestine with help from a carrier substance called intrinsic factor. Even though the gut bacteria in our colon produce a limited amount of intrinsic factor, we can only absorb vitamin B12 from the small intestine.
Vitamin B12 is important for our formation of red blood cells, our energy levels, our nervous system, our immune system, for normal functioning of DNA and cell division. The vitamin is stored in the liver, and we are able to recycle it to some extent. That is why it may take quite some time before a person on a strictly plant-based diet shows signs of being vitamin B12-deficient.
Lack of vitamin B12 is especially common in the underdeveloped countries, where large population groups cannot afford to eat animal food sources. In our part of the world, vegans and vegetarians are at increased risk of being vitamin B12-deficient. The same is the case with children of vegan and vegetarian mothers that have not taken a vitamin B12 supplement in connection with pregnancy and breastfeeding. In worst case, these children risk stunted growth and mental retardation.

  • Vitamin B12 is primarily known for its role in the formation of red blood cells
  • Vitamin B12’s importance for the brain and nervous system is often overlooked

Lack of vitamin B12 gives cause for concern

So far, no Spanish studies have looked closer at the nutritional status of vegetarians. In fact, the vitamin B12 deficiency problems worry scientists. The aim of the new study was to evaluate vitamin B12 and folic acid status in vegetarians and vegans by means of blood samples and different markers.
The study included 93 healthy adults. 44 were vegans and 49 were vegetarians that ate eggs and dairy products. 72.8 percent of the participants already took a vitamin B12 supplement. The scientists measured subclinical or clinical vitamin B12 deficiency in 11 percent of the participants. Thirty-three percent of the participants had elevated blood levels of homocysteine, a potentially harmful amino acid. The metabolism of homocysteine hinges on vitamin B12 and folic acid, and it is believed that elevated homocysteine levels increase your risk of atherosclerosis and blood clots.
The researchers observed that the participants who already took vitamin B12 supplements had healthier levels of both vitamin B12 and homocysteine. Yoghurt intake was only vaguely linked to improved vitamin B12 status.
Based on their findings, the researchers concluded that Spanish vegetarians and vegans get enough folic acid, but that subclinical and clinical vitamin B12 deficiency is widespread. Therefore, they recommend for vegetarians and vegans to take supplements of vitamin B12 to prevent severe deficiency symptoms.

  • Many vegetarians and vegans feel terrific and have no idea that it may last years before a vitamin B12 deficiency shows
  • Deficiency symptoms include fatigue, headaches, anemia, memory loss and other symptoms from the nervous system, or fertility problems
  • Lack of vitamin B12 may also harm children’s growth and learning abilities

Symptoms are often diagnosed incorrectly

Many vegetarians and vegans place a lot of focus on their diets. If both they and their children feel perfectly healthy, there is a risk that they may interpret the above-mentioned symptoms as a result of stress, dementia, or other diseases, simply because people react so differently to a vitamin B12 deficiency. It is therefore a good idea to inform your doctor if you have very strict diet habits. If the doctor suspects a vitamin B12 deficiency, a blood test can provide the answer.

Treating vitamin B12 deficiency

If your body’s vitamin B12 stores are seriously depleted, vitamin B12 injections are the best way to deal with the problem because they work fast. If a vitamin B12 deficiency is rooted in the diet, it is often enough to change your diet or take a vitamin B12 supplement. Vitamin B12 lozenges are better than tablets because the vitamin is taken up directly through the oral mucosa.
A vitamin B12 supplement should at least contain 2.5 micrograms of vitamin B12. People with pernicious anemia must be given vitamin B12 injections continuously because of the lack of intrinsic factor that is needed for absorbing the nutrient in the small intestine.

Vitamin B12 content in micrograms/100 grams

  • Calf liver 60
  • Cod roe 20
  • Liver pate 10
  • Salmon 4
  • Eggs 1.8
  • Shrimp 1,6
  • Cheese 1.5
  • Beef 1.4
  • Chicken 0.4
  • Vegetables and fruit 0
  • Nuts and kernels 0

Important: Vegetarians and vegans may even lack other nutrients

Many vegetarians and vegans have difficulty with getting enough protein, selenium, zinc, iron, and omega-3 fatty acids (EPA and DHA).


Angélica Gallego-Narbon et al. Vitamin B12 and folate status in Spanish lacto-ovo vegetarians and vegans. J Nutr Sci. 2019

Ebba Nexø. Vegetarer risikerer at få for lidt B12-vitamin. marts 2018

Uni Research. Children with poor B12 status early in life struggle more with tasks, recognition and interpreting feeling. ScienceDaily March 27, 2017

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