References used for all of the nutrient pages can be found at the bottom of the Nutrition Facts page. Click here.
Fortified Food Sources of B12
Food | B12 Content (mcg) |
Soymilk, 1 cup (unsweetened, Wildwood) | 3 |
Total cereal, 1 cup | 8 |
Raisin bran, 1 cup (Kellogg) | 2.5 |
Bite sized frosted wheat, 1 cup (365) | 1.5 |
Nutritional yeast, 1 tsp (Red Star VSF) | 0.9 |
Cultured coconut milk, 6 oz (Trader Joes) | 1.8 |
Meatless pepperoni slices, 10 (Yves) | 0.6 |
Meatless beef burger, 1 patty (Yves) | 2.4 |
Deficiency Symptoms
Toxicity Symptoms
Large amounts of B12 seem to be non-toxic
Excess B12 is excreted in the urine
How to Assess Status
Serum B12 is often ordered but the preferred test is a urine or blood test for methylmalonic acid (MMA)
Ask your physician for a MMA test if you are concerned about your B12 intake
Notes
The RDA for adults is 2.4 mcg/d but there is some new evidence that 4-7 mcg/d is optimal
The study that led to the 2.4 recommendation is over 50 years old and was based on only 7 subjects
Links
Dr. Michael Greger has a great set of videos on B12. Please check them out!
How Much B12 Do I Need?
RDA for Adults: 2.4 mcg/d
Upper Safe Limit for Adults: Not Determined
Why Do I Need B12?
B12 is needed to make red blood cells
Maintain nerve cells
Activate folate
Break down some fatty acids and amino acids
Vegan Sources
There are NO unfortified vegan sources for B12
B12 is produced by bacteria lining the gut of humans and animals
The B12 that our microbes produce is not absorbed because it is made in the colon beyond the absorption site
You may see claims that foods like tempeh, seaweed, miso and bean sprouts naturally contain B12 but these foods contain a B12 analog that is not active in our bodies
If you are following a strict vegan diet it is critical that you get a regular and reliable source of B12 through fortified foods or supplements
Many foods are fortified with B12 including some soymilks, breakfast cereals, non-dairy yogurts, nutritional yeasts and meat substitutes
Shoot for 3 servings of fortified foods daily or consider taking a supplement of either 250 mcg each day or 2500 mcg once a week
These recommended amounts for supplements are set high to account for absorption rates
Vitamin B12
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