The importance of vitamin B12 for our health is often underestimated. However, the risk of a vitamin B12 deficiency should by no means be ignored, especially when avoiding animal foods. An adequate supply cannot be achieved with plant-based foods alone.
Recent estimates indicate a high incidence of vitamin B12 deficiency in the vegetarian and vegan population, particularly among pregnant women and women of childbearing age, who are increasingly consuming plant-based foods for ethical and health reasons, reports an international research team in the European Journal of Nutrition.
Vitamin B12 important for health
According to the researchers, vitamin B12 plays a crucial role in metabolism throughout life and especially during pregnancy and early embryonic development. It has also been proven that a vitamin B12 deficiency is associated with an increased risk of a number of neurological, vascular, immunological and inflammatory disorders.
The body is dependent on an adequate supply of vitamin B12, which is not produced by plants, which is why unfortified plant foods are not a reliable source, explains Dr. Luciana Hannibal from the University Hospital Freiburg, Dr. Kourosh R. Ahmadi from the University of Surrey, Professor Martin Warren from the Quadram Institute Bioscience) and P. Julian Owen from the Cambridge University Hospitals NHS Trust.
Risk of vitamin B12 deficiency
If you do not eat animal-based foods, a vitamin B12 deficiency can quickly occur. “We would like to remind people who choose a plant-based diet and the health professionals who advise them how important it is to avoid vitamin B12 deficiencies,” the researchers emphasize.
The German Society for Nutrition (DGE) also emphasizes that “according to current knowledge, it is not possible to get vitamin B12 intake that is guaranteed to cover your needs exclusively with plant-based foods” and that the intake of vitamin B12 supplements is therefore recommended for vegan diets.
How much vitamin B12 does the body need?
According to the DGE, the estimated value for an adequate vitamin B12 intake in infants under the age of four months is 0.5 micrograms per day and increases to four micrograms per day up to the age of 13 years.
This value also applies to adults, although pregnant and breastfeeding women have an increased requirement of 4.5 micrograms per day and 5.5 micrograms per day, respectively, according to the DGE.
However, temporarily falling below the recommended daily intake is not a problem, since the body can store vitamin B12 in the liver until it is needed. If the intake of the vitamin is interrupted, the body stores normally last for three to five years, explains Dr. Larry E. Johnson of the University of Arkansas for Medical Sciences in an article for MSD Manuals.
Consequences of vitamin B12 deficiency
However, if a vitamin B12 deficiency develops, this can lead to anemia, among other things, which is characterized by paleness, weakness, tiredness and, in severe cases, shortness of breath and dizziness.
In addition, severe vitamin B12 deficiency can lead to damage to the nerves, accompanied by tingling or loss of feeling in the hands and feet, muscle weakness, loss of reflexes, difficulty walking, confusion and dementia, explains Dr. Johnson.
Furthermore, the current study by a research team from the Medical University of Lodz has shown that vitamin B12 deficiency also promotes DNA damage, which can be prevented by vitamin B12 supplementation.
Because vitamin B12 plays an important role in the stability of DNA, it acts as a cofactor for enzymes involved in the synthesis of nucleotides and has antioxidant properties, the researchers report.
Inadequate absorption most common cause
Finally, it should be mentioned that not only insufficient vitamin B12 intake through nutrition, but also insufficient absorption can trigger vitamin B12 deficiency. This is according to Dr. Johnson actually the most common cause.
Inadequate absorption can be caused, for example, by an overgrowth of bacteria in part of the small intestine, inflammatory bowel diseases, medications such as antacids and metformin (used to treat diabetes) or a lack of stomach acid (common in the elderly).
Blood test for diagnosis
A blood test can be used to determine relatively quickly whether there is a vitamin B12 deficiency, but finding the causes can be more difficult. The good news, however, is that whatever the cause, available treatments can correct the deficiency.
If a vitamin B12 deficiency is diagnosed by means of a blood test, countermeasures can be taken with high-dose vitamin B12 preparations, whereby the anemia and the corresponding symptoms usually subside quickly, explains Dr. Johnson. However, according to the specialist, the symptoms caused by nerve damage and the dementia may persist.
In addition to vitamin B12 preparations taken orally, vitamin B12 injections are also possible if required if the blood tests carried out regularly show no improvement through oral intake. If the cause of the deficiency cannot be eliminated, monthly injections are an option to ensure vitamin B12 supply.
In any case, if a vitamin B12 deficiency is suspected, a medical examination should be carried out promptly and people who largely avoid animal foods are generally advised to ensure their vitamin B12 supply by other means. (fp)