Vitamin B12: How Do Vegans Get It?

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Vitamin B12 Sources For Vegans

Getting vitamin B12 through food is a major challenge for vegans as nori and white button mushroom skin are the only natural sources with absorbable B12. Contrary to popular idea, seaweed and miso may do more harm than good as they contain inactive versions of B12 that hinder active B12 absorption. The other options are fortified cereals, rice, malt and cocoa-based milk, and supplements, which should be taken in small doses for maximum absorption.

If you are vegan or planning to become one, chances are that you’ve been warned of vitamin B12 deficiency. It’s scarily prevalent in people who shun any form of animal food. Nearly 40% of the American population suffers from low or near-deficient levels of B12,1 and vegetarianism has caused severe B12 deficiency in countries like India, Mexico, parts of Central and South America, and Africa.2

Vitamin B12 deficiency is rather common in vegetarians and vegans because this is the only vitamin that cannot be found in plant sources or sunlight.

A study found that vegans had a high concentration of the amino acid homocysteine from a deficiency in B12 in their bodies, almost 2 times that of vegetarians and 4 times that of omnivores.3Elevated homocysteine levels is associated with deadly diseases like cardiovascular ailments, stroke, and even certain kinds of cancer. Do you have vitamin B12 deficiency?

Vitamin B12 Is Produced Mostly In The Gut Of Animals

The reason you don’t get vitamin B12 from plants is that they do not need B12 and do not store it. It is commonly found in animal food like liver, clams, oysters, mussels, milk, eggs, fish, crab, lobster, beef, lamb, and pork. This vitamin gets its name, cobalamin, from the trace element called cobalt. Herbivorous animals like cows, bison, buffaloes, goats, antelopes, sheep, deer, and giraffe produce it in the gut with the help of gut bacteria. Horses, zebras, rabbits, elephants, hares, and some rodents get it either through gut bacteria, soil, or by eating their own body wastes. Primates get it through eggs, insects, and soil.4

Vitamin B12 Sources For Vegans

The recommended dietary allowance for vitamin B12 for men and women aged between 19 and 50 years are estimated to be 2 μg/day and 2.4 μg/day, respectively. But the body can take in only a limited amount of B12 at any given point of time. So take small doses more often.

The only two non-animal food items containing absorbable levels of vitamin B12 are white button mushrooms and nori.

1. White Button Mushroom And Nori

Recent research has found traces of vitamin B12 in the outer skin of white button mushrooms5 and in Korean purple laver, which is commonly called nori.6 Until now, these are the only two non-animal food items, which research says, contains absorbable levels of vitamin B12.

Seaweed, Tempeh, And Yeast May Not Help

Yeast, seaweed, or tempeh and miso may contain the inactive form of vitamin B12, which may interfere with absorption of active B12 in the body.

Although alternative sources like seaweed, fermented soy products like tempeh and miso, and yeast have been identified, whether they are reliable sources of this vitamin is debatable. This is because there are active and inactive forms of this vitamin in foods and the inactive form can actually interfere with vitamin B12 absorption in the body. These vegetarian sources were found to be lacking in active vitamin B12.7

If you cannot include the above-mentioned food items in your diet due to taste preferences, allergies, or availability issues, the only resort is to fall back on fortified food or B12 supplements.

2. Fortified Breakfast Cereals

Fortified breakfast cereals are the most readily available source of vitamin B12 for vegetarians, containing as much as 6 mcg vitamin B12 per serving.8Studies have proven that consumption of fortified cereal for breakfast or supper can increase the levels of vitamins B12, B1, B6, folate, and iron.9

3. Fortified Rice

Irrespective of how it is cooked, fortified rice is a good source of B12.10It has been proven that rice fortified with multiple micronutrients, including B12, improved the B-12 levels in Indian school children and significantly improved their physical performance.11

4. Malt And Cocoa-Based Milk

Fortified malt and cocoa-based milk (nut milk) help increase body weight, vitamin B12, red cell folate, and vitamin B2 in children.12

Vegan or vegetarian mothers need not worry about their babies’ vitamin B12 fix for the first 6 months as babies will get their B12 fix from breastmilk alone.13 Once breastfeeding is stopped, studies suggest that the nutrient gap can be filled with soymilk fortified with calcium and B12.

5. Supplements

Your body can’t absorb all the B12 available in supplements. And the smaller the dose, higher the absorption.

In dietary supplements, vitamin B12 is found in readily absorbable forms. But your body’s capacity to absorb it is still limited when compared to absorption from its natural forms. There’s no 100% absorption of vitamin B12 from supplements and the smaller the dose, the better the absorption. A study found that doses in the range of 0.1–0.5 µg resulted in 52–97% absorption; doses of 1 µg and 5 µg resulted in mean absorption of 56% and 28%, respectively; and 10 µg and 50 µg doses resulted in 16% and 3%, respectively, being absorbed.14

But supplements do work. In a study conducted in older men to see if supplements improved B12 intake, it was found that 80% of the users met the estimated average requirement (EAR) of the vitamin through supplements. 15

Can You Overdose On Vitamin B12?

A vitamin B12 overdose isn’t known to have any adverse or serious side effects. But always ask your doctor about B12 supplementation if you have abnormal level of red blood cells in the body, are pregnant, or are on other medications. But high B12 concentrations (most likely > 1,000 pmol/L) in the blood can lead to acne-like skin problems in some.16 It may also cause serious damage to optic nerves in people with Leber’s disease.17 So try to work with your diet, add in fortified food and supplements for your B12 requirement and stay healthy.

References   [ + ]

1. McBride, Judy. “B12 deficiency may be more widespread than thought.” United States Department of Agriculture (2000).
2. Stabler, Sally P., and Robert H. Allen. “Vitamin B12 deficiency as a worldwide problem.” Annu. Rev. Nutr. 24 (2004): 299-326.
3. Vitamin B-12 status, particularly holotranscobalamin II and methylmalonic acid concentrations, and hyperhomocysteinemia in vegetarians. The American Journal of Clinical Nutrition. July 2003.
4. B12 and Non-Human Animals. Vegan Health.
5. Koyyalamudi, Sundar Rao, Sang-Chul Jeong, Kai Yip Cho, and Gerald Pang. “Vitamin B12 is the active corrinoid produced in cultivated white button mushrooms (Agaricus bisporus).” Journal of agricultural and food chemistry57, no. 14 (2009): 6327-6333.
6. Miyamoto, Emi, Yukinori Yabuta, Chung Shil Kwak, Toshiki Enomoto, and Fumio Watanabe. “Characterization of vitamin B12 compounds from Korean purple laver (Porphyra sp.) products.”Journal of agricultural and food chemistry 57, no. 7 (2009): 2793-2796.
7. Reed Mangels. Vitamin B12 in the Vegan Diet. The Vegeterian Resource Group.
8. Vitamin B12- Fact Sheet. NIH.
9. Powers, Hilary J., Mark Stephens, Jean Russell, and Marilyn H. Hill. “Fortified breakfast cereal consumed daily for 12 wk leads to a significant improvement in micronutrient intake and micronutrient status in adolescent girls: a randomised controlled trial.” Nutrition Journal15, no. 1 (2016): 69.
10. Wieringa, Frank T., Arnaud Laillou, Christophe Guyondet, Vincent Jallier, Regina Moench‐Pfanner, and Jacques Berger. “Stability and retention of micronutrients in fortified rice prepared using different cooking methods.”Annals of the New York Academy of Sciences 1324, no. 1 (2014): 40-47.
11. Thankachan, Prashanth, Jee Hyun Rah, Tinku Thomas, Sumithra Selvam, Vani Amalrajan, Krishnamachari Srinivasan, Georg Steiger, and Anura V. Kurpad. “Multiple micronutrient-fortified rice affects physical performance and plasma vitamin B-12 and homocysteine concentrations of Indian school children.” The Journal of nutrition 142, no. 5 (2012): 846-852.
12. Kuriyan, Rebecca, Prashanth Thankachan, Sumithra Selvam, Maria Pauline, K. Srinivasan, Shilpa Kamath-Jha, Sophie Vinoy, Situn Misra, Yvonne Finnegan, and Anura V. Kurpad. “The effects of regular consumption of a multiple micronutrient fortified milk beverage on the micronutrient status of school children and on their mental and physical performance.” Clinical Nutrition 35, no. 1 (2016): 190-198.
13. Vegan Infants & Toddlers. Vegan Health.
14. Herbert, Victor. “Recommended dietary intakes (RDI) of vitamin B-12 in humans.” The American journal of clinical nutrition 45, no. 4 (1987): 671-678.
15. Sebastian, Rhonda S., et al. “Older adults who use vitamin/mineral supplements differ from nonusers in nutrient intake adequacy and dietary attitudes.” Journal of the American Dietetic Association 107.8 (2007): 1322-1332
16. Arora, Megha K., Shashi Seth, and Surabhi Dayal. “Homocysteine, folic acid and vitamin B12 levels in females with severe acne vulgaris.” Clinical Chemistry and Laboratory Medicine 50, no. 11 (2012): 2061-2063.
17. Vitamin B12. University Of Maryland Medical Center.
CureJoy Editorial

The CureJoy Editorial team digs up credible information from multiple sources, both academic and experiential, to stitch a holistic health perspective on topics that pique our readers' interest.

CureJoy Editorial

The CureJoy Editorial team digs up credible information from multiple sources, both academic and experiential, to stitch a holistic health perspective on topics that pique our readers' interest.