- Is B12 Vegan?
- Fortified Foods
- Brewer's and Nutritional Yeasts
- Safety of Supplements
- Chewing or Swallowing Whole
- Oral B12 for People with Malabsorption
- Non-cyanocobalamin Supplements
The vitamin B12 component in B12 supplements and fortified foods is made by bacteria and sourced from bacteria cultures; it is not taken from animal products. However, some companies might put gelatin in their B12 supplements, though this appears to be less and less common. It is easy to find vegan B12 supplements on the Internet or in grocery stores in developed countries.
There are some live food supplement companies that rely on spirulina or other algae, rather than bacteria cultures, as a source of vitamin B12. You should not rely on such products for your vitamin B12 as testing has indicated it is not a reliable source of active vitamin B12 (more information).
Streptomyces griseus, a bacterium once thought to be a yeast, was the commercial source of vitamin B12 for many years (8, 9). The bacteria Propionibacterium shermanii and Pseudomonas denitrificans have now replaced S. griseus (10). At least one company, Rhone Poulenc Biochimie of France, is using a genetically engineered microorganism to produce B12 (11).
There are many vegan foods fortified with B12. They include non-dairy milks, meat substitutes, breakfast cereals, and one type of nutritional yeast.
The "Daily Value" for B12 found on food labels is based on 6 µg, which was the RDA in 1968. If a label says a food has, for example, 25% of the Daily Value of B12, it has 1.5 µg (25% of 6 µg = 1.5 µg).
Brewer's and nutritional yeasts do not contain B12 unless they are fortified with it. There is at least one vegan, B12-fortified yeast currently on the market: Red Star Vegetarian Support Formula. (Twinlab's SuperRich Yeast Plus contains whey).
Unfortunately, there are some drawbacks to relying solely on B12-fortified nutritional yeast for B12:
- Nutritional yeast often comes from bins in health food stores. If not careful, it would be easy for a store employee to order the wrong nutritional yeast out of the distributor catalogs which often list many yeasts. It would also be easy to accidentally put the wrong yeast into the Vegetarian Support Formula bin.
- B12 is light sensitive. Nutritional yeast is likely to be exposed to the light because it is often stored in clear bins or plastic bags.
- At least one vegan who thought he was getting B12 from nutritional yeast developed B12 deficiency symptoms that cleared up upon taking a B12 supplement.
If you are trying to use Red Star Vegetarian Support Formula for B12, make sure you are actually getting what you think. It is also best to keep it in the refrigerator or freezer, out of the light.
Please note: Red Star Vegetarian Support Formula nutritional yeast has many other nutrients and I eat it myself; but vegans shouldn't rely on it for their sole source of B12, in my opinion.
Tucker et al. (2000, USA, 13) found that vitamin B12 from fortified breakfast cereals and dairy products was associated with better vitamin B12 status than was B12 intake from red meat, poultry, and fish, leading the researchers to suspect that the B12 from meat might be damaged by cooking. The B12 in animal foods tends not to be cyanocobalamin, the form used in fortified foods and that is more stable during cooking. For example, in an acid medium (pH 4-7), cyanocobalamin can withstand boiling at 120° C (1).
Even so, for people wondering whether they are destroying the B12 in their fortified foods by cooking, we do not have enough evidence to know for certain, so it is safest to make sure you rely on uncooked sources of vitamin B12.
There are some concerns about vegans relying solely on multivitamins that contain only small amounts of B12 (less than about 25 µg):
- Herbert et al. (2) (1982, USA) reported that vitamins B1, B3, C, and E, and copper and iron can damage B12. They tested 15 multivitamin preparations used daily by approximately 100 million Americans for inactive B12 analogues and all preparations contained some (6-27% of total corrinoids).
- Vitamin C in doses of 500 mg or more taken with meals or within one hour after a meal, may diminish B12 availability or destroy the B12 (3).
- Many multivitamins cannot be chewed, which is important for B12 absorption in some people.
That said, if a multivitamin is chewable and has 25 µg of B12 (as cyanocobalamin) or more, and taken daily, it is most likely adequate.
In 1988, Herbert cautioned that large amounts of B12 may eventually be found to be harmful (4). In contrast, Hathcock & Troendle (5) (1991) point out that there appears to be little or no question that B12 intakes of 500-1000 µg/day are safe. The Institute of Medicine has not set an Upper Tolerable Limit for a daily vitamin B12 intake.
The cobalt and the cyanide contribution of 1000 µg/day of cyanocobalamin are considered toxicologically insignificant (5). People with chronic kidney failure, cyanide metabolism defects, and probably smokers should take a different form of B12.
Crane et al. (6) (1994, USA) noted that tablets of one vitamin company dissolved slowly in water and acid. They then conducted a study to see if vegan patients who had not previously responded to oral B12 tablets swallowed whole could improve their B12 response by chewing the tablets. 7 people chewed the tablets of 100 µg (once a week for 6 weeks) and their average serum B12 levels went from 116 to 291. Of the 9 who didn't chew, theirs increased from 123 to only 139. (However, a 100 µg dose once a week is not a lot of B12. The more surprising result of this experiment was the large increase in the serum B12 of the 7 people who chewed the tablets, not the small increase of those who did not chew.)
7 of these 9 then chewed 500 µg/day for 10 days and their levels rose to normal with a final average of 524 ± 235. Three participants could not raise their levels orally and required B12 injections to maintain serum B12 above 300.
A 2003 study compared 500 µg per day via the sublingual (under the tongue) and oral routes. The results were that sublingual was no better than oral B12 at raising vitamin B12 levels or improving B12 activity (as measured by homocysteine and methylmalonic acid levels). Both routes increased vitamin B12 levels effectively (12).
Some recent studies have shown that taking large amounts of oral B12 can normalize B12 status even in people with pernicious anemia. For more information, see Oral B12 for People with Malabsorption in How Recommendations Were Formulated.
In addition to cyanocobalamin, there are oral supplements available for methylcobalamin, adenosylcobalamin (known in the supplement industry as dibencozide and coenzyme B12), and to a lesser extent, hydroxocobalamin. See Non-cyanocobalamin B12 Supplements. As mentioned above, these forms of B12 may be preferable for vegan smokers.
S-adenosylmethionine (aka SAM and SAMe) is another supplement that has received attention. It is found in the homocysteine-methionine pathway, and some people think it may be relevant to B12 status in people who have been B12 deficient. More information is in SAMe.
2. Herbert V, Drivas G, Foscaldi R, Manusselis C, Colman N, Kanazawa S, Das K, Gelernt M, Herzlich B, Jennings J. Multivitamin/mineral food supplements containing vitamin B12 may also contain analogues of vitamin B12. N Engl J Med. 1982(July);307(4):255-6.
10. De Baets S, Vandedrinck S, Vandamme EJ. Vitamins and Related Biofactors, Microbial Production. In: Lederberg J, ed. Encyclopedia of Microbiology, Vol 4, 2nd Ed. New York: Academic Press; 2000:837-853.
12. Sharabi A, Cohen E, Sulkes J, Garty M. Replacement therapy for vitamin B12 deficiency: comparison between the sublingual and oral route. Br J Clin Pharmacol. 2003 Dec;56(6):635-8. | link
13. Tucker KL, Rich S, Rosenberg I, Jacques P, Dallal G, Wilson PW, Selhub J. Plasma vitamin B-12 concentrations relate to intake source in the Framingham Offspring study. Am J Clin Nutr. 2000 Feb;71(2):514-22. | link