Vitamin B12 deficiency: cause, symptoms, among vegans?

Vitamin B12 deficiency is often linked to a specific diet such as flexitarian, vegetarian or vegan. Pauline Fernandez, dietician and nutritionist, explains the characteristics of this deficiency.

Vitamin B12, also called cobalaminis a water-soluble vitamin essential to the normal functioning of the brain, nervous system and the formation of red blood cells. She comes mainly from food (offal meat, fish and shellfish). What are signs of a deficiency in vitamin B12? Is it more common among vegetarians?

What are the symptoms of vitamin B12 deficiency?

Symptoms of vitamin B12 deficiency are diverse and mainly result in nervous disorders : “delirium, cognitive function disorders, depression, irritability, insomnia, numbness of limbsa loss of taste, balance and gait disturbances, tinnitus, restless leg syndrome…it can also impact erectile function “, describes Pauline Fernandez, dietician and nutritionist. Dysfunctions in hematopoiesis can also be observed: macrocytic anemia. Other symptoms can be added to this long list: infertility, amenorrhea (lack of rules), skin hyperpigmentation, fatigue, nausea, digestive disorders, osteoporosis and risk of fractures. “There are many symptoms that are not necessarily specific to vitamin B12 deficiency. This is why the diagnosis is not always obvious.“, she underlines.

What causes vitamin B12 deficiency?

The reduced consumption of meat, fish, eggs and dairy products can lead to vitamin B12 deficiency. “The decrease in vitamin B12 levels will be observed over time: it depends on the initial level and can decrease slowly depending on the changes made in the diet. The first two years of a flexitarian diet, it is possible that the B12 level remains within the norm, it is rather over time that this deficiency sets in“, adds Pauline Fernandez. Certain antacid medications by reducing gastric acidity limit the release of vitamin B12 contained in food. Aging due to the decrease in gastric secretions can also lead to B12 deficiency. Biermer’s disease, gastritis linked to Helicobacter Pylori, malaria, tuberculosis as well as the consumption of alcohol and tobacco lead to vitamin B12 deficiency. The needs are also increased during the pregnancy and breastfeeding.

Is it more common among vegetarians?

Vitamin B12 deficiency is more common in vegetarians and vegans because the intakes are not sufficient in the daily diet. “There are many forms of vegetarianism (elimination of meat only, elimination of meat and fish, etc.) and it is necessary to assess the frequency of consumption of each food source of vitamin B12 to accurately calculate the weekly intake.“.

What is the treatment for vitamin B12 deficiency?

It is from a blood test that we will determine vitamin B12 deficiency. If anemia is suspected, vitamin B9 and iron will also be measured. The Vegan Federation of France recommends in addition the dosage of methylmalonic acidcarried out in the urine, to avoid diagnostic errors. Vitamin B12 supplementation will thus be implemented based on these results. There are several types, the most absorbed is the cobalamin. In vegetarians, the daily intake is 15-25 μg/d and up to 100 μg/d in vegans and if the dosage is weekly, it increases to 2000 μg/d. “The dosage depends on the compliance of the person: it can be daily, weekly or monthly. If food avoidance continues, lifelong supplementation should be considered“. This treatment can be treated under medical prescription.

Thanks to Pauline Fernandez, dietician, nutritionist, therapeutic hypnosis in Toulouse.

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