Vitamins and mineralsVitamin B12 for vegans — essential supplement or overkill?
- Henryk Różański — Witamina B12 – doustnie i pozajelitowo
- Jerzy Zięba — Witamina B12 - metylokobalamina
- Henryk Różański — Witamina B12
- A systematic review and meta-analysis of functional vitamin B12 status among adult vegans. · Nutr Bull 2024
- Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. · J Acad Nutr Diet 2016
- [Vitamin B12, fatty acids EPA and DHA during pregnancy and lactation in women with a plant-based diet]. · Nutr Hosp 2024
- Vegan or vegetarian diet and breast milk composition - a systematic review. · Crit Rev Food Sci Nutr 2021
- Health aspects of vegan diets among children and adolescents: a systematic review and meta-analyses. · Crit Rev Food Sci Nutr 2024
- Health effects of vegan diets. · Am J Clin Nutr 2009
- Maternal and newborn health in vegan and omnivore pregnancies: A prospective pilot study (PREGGIE). · Nutr Health 2026
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Henryk Różański says that an entirely plant-based diet is an indication for taking vitamin B12, because plants contain too little of it for humans.
- According to him, the body must get ready-made B12 from food, while vitamin B12 produced in the large intestine is excreted in the stool.
- Różański suggests about 10 µg of B12 a day in a supplement, while Jerzy Zięba gives recommended amounts of 2.4–2.8 µg a day, depending on the group.
- Zięba says that a deficiency can lead to anemia and neurological and psychiatric diseases.
What the authors write
Plants contain too little vitamin B12 for humans.
An entirely plant-based diet is listed as an indication for taking vitamin B12.
Vegans are listed among people who use B12 to prevent deficiencies related to diet or increased needs.
Henryk Różański says that the body must get ready-made B12 from food and that B12 produced in the large intestine is not absorbed there.
Henryk Różański repeats that B12 produced by microorganisms in the large intestine is excreted in the stool instead of supplying it to the body.
Henryk Różański mainly lists animal products as rich sources of B12 and gives 5 µg as the daily requirement, noting that some sources give 1–2 µg.
Jerzy Zięba gives recommended amounts of 2.4–2.8 µg a day, depending on the group, and a maximum of 100 µg in the recommended daily serving of a supplement.
Henryk Różański suggests taking about 10 µg of B12 a day as a supplement.
Henryk Różański describes that after taking 1 mg of B12 by mouth, about 1% is absorbed through passive diffusion.
Jerzy Zięba says that B12 deficiency can lead to anemia and neurological and psychiatric diseases, while excess B12 may be associated with higher mortality.
Jerzy Zięba lists animal products as sources of methylcobalamin and says that it is also available in tablets as a supplement.
Jerzy Zięba says that vitamin B12 is synthesized in the human digestive tract.
Research from PubMed · Europe PMC
We selected 7 studies with the best, positive results. This is a selection, not a full review of all research.
Total number of studies on this topic in PubMed: 294.
A meta-analysis found that vegans have poorer functional vitamin B12 status, and that supplements are associated with better B12 status.
Aim of the study: The dietary intake of vitamin B12 among unsupplemented vegans is notably lower compared to both vegetarians and omnivores. Prolonged low intakes of vitamin B12, such as seen in those adhering to a vegan diet, lead to physiological deficiency of vitamin B12 and an elevated risk of B12-related morbidity.
Results: Meta-analysis results revealed significantly lower serum B12, pmol/ (-0.72 [-1.26, -0.18]; p = 0.01) and elevated total homocysteine, μmol/L (tHcy) (0.57 [0.26, 0.89]; p < 0.001) concentrations, alongside elevated methylmalonic acid, nmol/L (MMA) (0.28 [-0.01, 0.57]; p = 0.06) and lower holotranscobalamin, pmol/ (HoloTC) (-0.42 [-0.91, 0.07]; p = 0.09) levels among vegan adults compared to omnivores, indicating increased functional B12 deficiency in addition to low vitamin B12 status in vegan adults. There were no differences between vegans and vegetarians in HoloTC (0.04 [-0.28, 0.35]; p = 0.814) or MMA (-0.05 [-0.29, 0.20]; p = 0.708), but differences were found in serum B12 (-0.25 [-0.40, -0.10]; p = 0.001) and for tHcy (0.24 [0.09, 0.39]; p = 0.002) concentrations. Subgroup analyses indicated that the use of vitamin B12 supplements among vegans contributes to significant improvements in all biomarker concentrations compared to their unsupplemented counterparts.
“Not stated” does not mean nobody paid — the database does not always record it.
The Academy’s position recommends that vegans have a reliable source of B12, such as fortified foods or supplements.
Aim of the study: It is the position of the Academy of Nutrition and Dietetics that appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases. These diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence, older adulthood, and for athletes.
Results: Vegetarians and vegans are at reduced risk of certain health conditions, including ischemic heart disease, type 2 diabetes, hypertension, certain types of cancer, and obesity. Low intake of saturated fat and high intakes of vegetables, fruits, whole grains, legumes, soy products, nuts, and seeds (all rich in fiber and phytochemicals) are characteristics of vegetarian and vegan diets that produce lower total and low-density lipoprotein cholesterol levels and better serum glucose control. These factors contribute to reduction of chronic disease. Vegans need reliable sources of vitamin B-12, such as fortified foods or supplements.
“Not stated” does not mean nobody paid — the database does not always record it.
A review found that B12 supplementation was associated with higher plasma levels of the vitamin in women following a plant-based diet.
Aim of the study: Pregnancy and lactation represent a complex stage from a nutritional point of view, since energy, protein and micronutrient requirements increase during these stages. The literature describes that a well-planned plant-based diet can be sufficient in energy, macronutrients and micronutrients, with the exception of vitamin B12 and possibly n3 polyunsaturated fatty acids, mainly EPA and DHA.
Results: Eleven articles were selected in this review. Well-planned vegetarian and vegan diets, with adequate supplementation of vitamin B12, EPA and DHA, are compatible during pregnancy and lactation, being a positive predictor of their content in breast milk. A similar situation was observed in plasma levels in women supplemented with B12. However, it is important to continue with research in this area that considers an adequate dietary anamnesis, integral evaluation of nutritional status, estimation of nutritional requirements and an individualized nutritional plan.
“Not stated” does not mean nobody paid — the database does not always record it.
The review indicates that vegan mothers can produce nutritionally valuable milk if they receive adequate supplements to meet their needs.
Aim of the study: It is known that nutritional composition of breast milk is, to a certain extent, related to maternal diet. The question of nutritional adequacy of mothers' milk is often raised whenever a vegetarian or vegan diet during the lactation process is concerned.
Results: The systematic review has shown that all non-vegetarian, vegetarian and vegan mothers produce breast milk of comparable nutritional value. Several differences are primarily attributed to fatty acids and some micro-components, primarily vitamin B12. Regardless of dietary choices, nourishment and adequate nutrition have a significant impact on human milk composition - on the basis of the current evidence, vegetarian and vegan mothers are capable of producing nutritionally valuable milk for their infants, as far as the appropriate supplementation compensating for breastfeeding mother's nutritional requirements is provided. Dietary choices should not be a permanent exclusion criterion for donor candidates in human milk banks.
“Not stated” does not mean nobody paid — the database does not always record it.
Blood B12 levels were higher in vegan children, which the authors linked to supplement use.
Aim of the study: Health effects of vegan diets among children and adolescents are a controversial public health topic. Thus, the aim of the present systematic review is to evaluate a broad range of health outcomes among vegan children and adolescents aged 0 to 18 years.
Results: Single study results suggested further differences between vegan and non-vegan children, such as lower bone mineral content or urinary iodine among vegan children. Risk of Bias was rated as high or very high in 7 out of 18 studies. The certainty of evidence for the meta-analyses was low (n = 2) or very low (n = 46). Overall, the available evidence points to both risks and benefits associated with a vegan diet among children, although more and better designed studies are needed.
“Not stated” does not mean nobody paid — the database does not always record it.
The review recommends that vegans regularly eat foods fortified with B12 or take appropriate supplements.
Aim of the study: Recently, vegetarian diets have experienced an increase in popularity. A vegetarian diet is associated with many health benefits because of its higher content of fiber, folic acid, vitamins C and E, potassium, magnesium, and many phytochemicals and a fat content that is more unsaturated.
Results: However, eliminating all animal products from the diet increases the risk of certain nutritional deficiencies. Micronutrients of special concern for the vegan include vitamins B-12 and D, calcium, and long-chain n-3 (omega-3) fatty acids. Unless vegans regularly consume foods that are fortified with these nutrients, appropriate supplements should be consumed. In some cases, iron and zinc status of vegans may also be of concern because of the limited bioavailability of these minerals.
“Not stated” does not mean nobody paid — the database does not always record it.
A small study found no clear adverse effects of a supplemented vegan diet during pregnancy, including vitamin B12.
Aim of the study: BackgroundFew studies have assessed health outcomes in pregnant vegans and their newborns.AimThis study aimed to examine this evidence gap.MethodsThis pilot study compared health parameters of pregnant vegans (n = 32) and omnivores (n = 13), as well as their newborns, in Germany (2019-2022). Maternal body mass index, weight and blood pressure were measured at gestational weeks 9-16 (t1) and 35-38 (t2).
Results: An Apgar score <10 at 10 min was recorded in 1 vegan (3%) and 1 (8%) omnivore newborn (both scoring 8).This study detected no clear adverse effects of a supplemented vegan diet (vitamin B12, iodine, vitamin D, omega-3 fatty acids) during pregnancy. Differences between vegans and omnivores cannot be excluded. The study was underpowered and baseline differences limit group comparability, validity, and generalizability. The study highlights key parameters and underscores the need to maximize group comparability in future research.
“Not stated” does not mean nobody paid — the database does not always record it.
Perspectives and opinion materials
The content below presents the authors’ opinions, interpretations and hypotheses. It is not treated as equal to scientific studies and systematic reviews.
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