Optimizing Nutrition for Vegans: Vitamin B12

Optimizing Nutrition B12.png

Disclaimer: I can’t make personalized supplement recommendations without completing an assessment and knowing your health background. This blog post is for informational purposes and not intended to be a substitute for recommendations from your doctor or dietitian.

Okay, are you ready to nerd out with me a bit and learn more about nutrients necessary to be a happy, healthy vegan? In this series, we’ll examine some important nutrients crucial to good health, how to get them in your diet, as well as some tips on cultivating a healthy relationship with food.

We’ll begin with Vitamin B12 as it’s the one supplement that all vegans absolutely should be taking regularly!

Vitamin B12 is a water-soluble vitamin produced by bacteria and found in animal products. B12 is involved in the formation of red blood cells, the creation of DNA, is necessary for the normal function of the brain and nervous system, and used in cell metabolism.

WHo should supplement?

B12 deficiency is found in 1.5-15% of the general population. Various studies have shown that anywhere between 11-90% of vegans tested were deficient in B12. Deficiency can be caused by malabsorption issues, autoimmune conditions, and dietary insufficiency. Malabsorption can be due to a number of things, including intestinal disorders such as Crohn’s disease, certain medications, and reduced stomach acid. In many cases, the cause of deficiency is unknown. I think it’s safe to say that most vegans who are deficient are simply not getting enough B12 from fortified foods or supplements.

People over 50 years old are also more likely to have B12 malabsorption issues and should have their levels tested and take a sublingual supplement if necessary. Those who are unable to absorb sufficient B12 from food or supplements may need B12 injections.

Signs/symptoms of deficiency include megoblastic anemia, fatigue, weakness, pale skin, heart palpitations, a smooth tongue, numbness or tingling, muscle weakness, difficulty walking, vision loss, dementia, and depression. Nerve damage and other effects of deficiency can be permanent, so getting sufficient B12 is extremely important. Unfortunately it’s something I sometimes see vegan advocates downplaying. Not cool!

Supplement Guidelines 

The RDA for adults is 2.4 mcg (micrograms) per day (2.6 mcg if pregnant & 2.8 mcg if breastfeeding). Vegans/vegetarians who consume few animal products will want to supplement vitamin B12 and/or consume fortified foods. When getting your B12 from fortified foods, aim for three servings per day, with at least 2 mcg per serving. Foods that may be fortified include dry cereals, plant-based milks and yogurt (soy, almond, cashew, etc.), meat substitutes, and some brands of nutritional yeast (such as Red Star or Bragg). It’s important to check the nutrition label on foods to ensure they are fortified with B12 before relying on them as a sole source!

Most supplements are well over 2.4 mcg and that’s okay! You can take 25-100 mcg daily or 1000 mcg twice per week. Our bodies can only absorb so much B12 at one time and will excrete any excess. Needs will be higher to correct a deficiency.

B12 supplements are found as cyanocobalamin and methylcobalamin (the active form). Cyanocobalamin is easily converted into the active form in our bodies unless you have kidney disease or smoke cigarettes. Due to cyanocobalamin being more widely researched, supplement dosages are based on this form. Some research suggests a higher amount of methylcobalamin is needed (1500 mcg per day) due to its instability in this form so if you choose to take methylcobalamin keep this in mind.

There seems to be some confusion/debate about certain foods like seaweeds, mushrooms, unwashed organic produce, and fermented foods containing B12. They may contain an analogue form of B12 that does not have the same vitamin activity. These are NOT reliable sources.

If in doubt, ask your doctor to check your levels! More on lab tests to determine B12 status here. B12 supplements are widely available and it isn’t worth the risk to your health to miss out on this critical vitamin.

A few fun ways to get more vitamin B12 through fortified foods (make sure you’re using a fortified nutritional yeast in recipes):

Vegan queso from Cookie and Kate

Vegan broccoli and cheese soup from Oh She Glows

14 Vegan Foods and Drinks Fortified With B12


  • Vitamin B12 is important for vegans or those with certain autoimmune or malabsorption issues to regularly supplement.

  • Supplement recommendations for adults: 25-100 mcg daily or 1000 mcg twice per week.

  • If relying on fortified foods: 3 servings per day of at least 2 mcg B12 per serving.

For more detailed info on B12 check out Vegan Health’s article.


Langan RC, Goodbred AJ. Vitamin B12 Deficiency: Recognition and Management. Am Fam Physician. 2017 Sep 15;96(6):384-389. PubMed PMID: 28925645

NIH Office of Dietary Supplements: Vitamin B12 Fact Sheet for Health Professionals

Ankar A, Bhimji SS. Vitamin B12 Deficiency (Cobalamin) [Updated 2018 Oct 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2018 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK441923/

Vegan Health: Methylcobalamin and Adenosylcobalamin

The Vegan RD: Vitamin B12: A Vegan Nutrition Primer

Tell me in the comments: are you making sure you meet your B12 needs? Do you have any questions about vitamin B12?