In debates, the contra side often claims veganism can’t be good because vegans have to supplement B12 (appeal to nature), while the pro side sometimes claims that even carnists supplement B12 indirectly because the animals get B12 supplements.

I would like to find out to which extent the latter statement is true/relevant.

How common is it for the livestock industry to supplement B12? Does it only affect certain countries, animal species, farming methods, …?

And why does the livestock industry supplement B12 in the first place? Does it only get supplemented for the benefit of the human consumers, or is it required for the animals to live long enough for the industry’s goals? Or both, so more B12 gets supplemented than the animal would need?


1 Answer 1


There are a lot of interesting questions you pose and some are addressed in the article Do carnivores need Vitamin B12 supplements?.

  1. Let's first look at the claim that vegetarianism must be unhealthy because they need to supplement B12. According to the excerpt below, it appears that both meat eaters and vegetarians are equally deficient in B12.

    The Framingham Offspring study found that 39 percent of the general population may be in the low normal and deficient B12 blood level range, and it was not just vegetarians or older people. Most interestingly there was no difference between those ate meat, poultry, or fish and those who did not eat those foods. The people with the highest B12 blood levels were those who were taking B12 supplements and eating B12 fortified cereals.

  2. Next, let's examine why modern meat no longer supplies an adequate amount of B12.

    [B12] is made by bacteria that live in soil and in the guts of animals. Cattle and other grass-eating animals get B12 and B12 producing bacteria from clumps of dirt around the grass roots that they pull up. Chickens and other birds get B12 from pecking around for worms and other insects. These animals store B12 mostly in their livers and muscles and some B12 pass into milk and eggs.

    But, cattle no longer feed on grass and chickens do not peck in the dirt on factory farms. Even if they did, pesticides often kill B12 producing bacteria and insects in soil. Heavy antibiotic use kills B12 producing bacteria in the guts of farm animals.

  3. Your question about frequency is difficult to precisely answer but the article does state:

    In order to maintain meat a source of B12 the meat industry now adds it to animal feed, 90% of B12 supplements produced in the world are fed to livestock.

  4. As for if the animals need the B12 to be healthy, according to this article about sheep and cows, the answers seems to be yes. They need b12 for similar reasons as humans.

    Vitamin B12 is essential for cell growth and maturation, energy production and wool growth. In general, sheep are more susceptible to Vitamin B12 deficiency than cattle are. Rapidly growing animals (i.e. lambs/calves and weaners) are most likely to develop a B12 deficiency and will suffer most badly when a deficiency develops.

    Clinical signs of Vitamin B12 deficiency include weight loss, suppressed appetite, decreased feed efficiency, anaemia, diarrhoea, rough coat, scaly ears and weepy eyes.

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