What's the B12 content in fermented rice / gruel (eg. shown at https://www.youtube.com/watch?v=ylKMMCxXZI8 )?

Internet search yields conflicting information, even regarding other fermented Indian food like idli and dosa.

1 Answer 1


The video makes a claim that is incorrect (both in the video and in the description). The wrong claim is that B12 produced by intestinal flora is absorbed by the body. The implication is that consumption of probiotics will aid B12 deficiency by increasing B12-producing intestinal flora. Unfortunately it seems to be the case that while some intestinal flora do produce B12, this B12 produced in the gut is not absorbed and does not prevent B12 deficiency. There is also no evidence that I know of that fermented foods can effectively prevent or treat B12 deficiency.

I strongly advise vegetarians and especially vegans to take B12 supplements. B12 supplements are inexpensive and reliably treat and prevent B12 deficiency. Even if some fermented foods may sometimes contain B12, there is no fermented food that has been shown to reliably prevent B12 deficiency. There may be many health benefits to eating fermented foods and they may be very delicious to eat, but they should not be relied on as sources of vitamin B12.

  • Neither the video nor the description claim that B12 produced by intestinal flora is absorbed by the body. Neither is there such an implication. Perhaps you refer to "replenishment of microflora" mentioned around here - youtu.be/ylKMMCxXZI8?t=565 ? On the other hand, she does claim that the fermented rice/ gruel is already rich in b12. The second paragraph is ok - yet I remain puzzled by how at-least some individuals in traditional vegetarian societies lived long healthy lives. Nov 1, 2023 at 23:21
  • @vishvAsvAsuki Here in India, vegetarianism has been common for a long time but it includes milk and milk products. I don't know any long term vegan societies. Do you?
    – badjohn
    Nov 2, 2023 at 1:25
  • I don't know of any long term vegan society; and I too come from an Indian vegetarian community. Despite wide and significant diary consumption, B12 deficiency is very common (atleast in several city families here). Presumably, adult diary consumption doesn't suffice. Nov 2, 2023 at 4:11
  • I am referring to "This traditional recipe is amazing for vegetarians as it helps the body synthesize and absorb Vitamin B12." Btw, one important reason for older people to become increasingly deficient in B12 (including non-vegetarians) is the reduced production of intrinsic factor as we age. Many elderly people including non-vegetarians are prescribed B12 injections.
    – Zanna
    Nov 2, 2023 at 11:33
  • I also wonder about this, because I believe most people (i.e. poor people) ate very little non-vegetarian food until recently. As mentioned by badjohn, dairy products provide B12, but they are quite a new introduction to the human diet, and not consumed everywhere. It may be the case that people consumed more B12 in the past because of differences in agricultural practices and food preparation. In any case, the hazard of B12 deficiency is a reality in the contemporary world. Another nutritional mystery is how toddlers got enough iron before baby cereal was invented...
    – Zanna
    Nov 2, 2023 at 11:39

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