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Fortified Food Sources of B12
B12 Content (mcg)
Soymilk, 1 cup (unsweetened, Wildwood)
Total cereal, 1 cup
Raisin bran, 1 cup (Kellogg)
Bite sized frosted wheat, 1 cup (365)
Nutritional yeast, 1 tsp (Red Star VSF)
Cultured coconut milk, 6 oz (Trader Joes)
Meatless pepperoni slices, 10 (Yves)
Meatless beef burger, 1 patty (Yves)
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
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
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
Break down some fatty acids and amino acids
There are NO unfortified plant-based 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
Our plant eating ancestors likely consumed enough B12 through plants and fresh water sources that were contaminated with B12 producing bacteria
Today we have a very sanitary water and food supply so the safest way to get B12 is through fortified plant foods or supplements
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 plant-based 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
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