B12: A Magic Pill, or Veganism’s Achilles Heel?

b12 vegans

There are more than 700 million stray cats and dogs in the world. In the U.S. alone 4 million are killed in shelters every year.

Consider the following hypothetical proposition. Suppose there were a magic pill that, if everyone took it, would prevent millions of stray dogs and cats from being rounded up, locked in lonely stalls, and dying terrified and confused on a cold, steel euthanizing table. If everyone took this magic pill, there would effectively be no more stray cats or dogs, and no more kill shelters. If only some people took this pill, there would still be some stray cats and dogs, but millions fewer would exist. And if you alone took this pill, 200 fewer miserable shelter animals would be bred and killed each year. Would you take the pill?

Now let’s say this pill isn’t just a magic pill that can cure the world of stray dog and cat suffering. It’s also a healthful vitamin your body already needs; call it vitamin V. In this scenario, vitamin V is something that many people, regardless of diet, commonly suffer a shortage of, so that it is already recommended that everyone over the age of 50 take a vitamin V supplement. Taking a vitamin V supplement poses no health risks, will not cause you to have too much vitamin V, and 100 tablets, or a 3-6 months supply, costs about $5 on average. And again: taking vitamin V, in addition to providing your body with an essential nutrient, will help prevent millions of animals from suffering and dying. Would you take the pill?

Reframing B12 and veganism

b12 and veganism

113,000,000 pigs were slaughtered in 2012 in the U.S. Photo: Snooters Sanctuary

While there’s no magic pill to prevent the tragic plight of millions of stray cats and dogs — the solution there is to stop breeding companion animals and purchasing them from breeders— the reality is that in supplemental vitamin B12, we do have something very like a magic pill against the unspeakable suffering and unnecessary execution of billions of animals every year: 60 billion cows, pigs, chickens, turkeys, sheep and goats bred into existence for the sole purpose of being slaughtered. Yet, the need for vegans to supplement their diets with B12 is generally treated like veganism’s Achilles heel, rather than celebrated as an easy way for each of us to cause vastly less suffering and death in the world.

Vitamin B12 is the only nutrient essential to human health that can not be obtained from plants or sunlight. B12 is crucial to normal brain and nervous system function, and to the formation of healthy blood cells. It also plays a central role in DNA synthesis and cell metabolism. And it is sometimes argued that because B12 is not produced by plants, vegan diets are “unnatural” and that ethical appeals to veganism are therefore misguided. But there are several flaws with this objection.

B12 is not produced by plants OR animals.

While it is true that plants do not produce vitamin B12, neither do animals inherently produce it. B12 is produced by bacteria that live in the soil and in the intestines of animals, including humans; however, in humans and other animals, it is generally manufactured too far down the intestinal tract (in the colon, in our case) to be absorbed, and is instead excreted in feces, where it is abundant.

B12 absorption

Diagram by Dr. Jennifer Rooke, M.D., M.P.H. Used with permission.

b12 humanure

Some animals get their B12 naturally by consuming their own feces.

In a 1959 study, when a community of vegans living in Iran was found to have no B12 deficiency despite the fact that none of them took a B12 supplement, researchers were confounded until it was discovered that the villagers grew their vegetables in “night soil” — that is, soil heavily composted with human manure. (1) Another study found that humans suffering from B12 deficiency were able to replenish their B12 levels by consuming their own feces, as several animals do for precisely this reason. (2) Rabbits, possums and guinea pigs, for example, produce two types of excrement: hard daytime pellets they leave behind, and softer B12-rich pellets intended for nightly consumption.

It is commonly theorized that in the nonindustrialized world, bacterial contamination from soil or feces brings traces of B12 to plant foods in sufficient amounts to prevent B12 deficiency in humans who do not consume animal products, or in areas where animal foods do not make up a significant portion of the diet; but that in the industrial world, modern food sanitation practices combined with heavy mineral depletion of soils from pesticides and crop monoculture have eliminated this source of vitamin B12, just as indoor living has largely eliminated sunlight as our natural source of vitamin D.

Most farmed animals are not a natural source of B12.

Cattle, sheep and other ruminants have ample B-12 producing bacteria in the first chamber of their four-chambered stomachs, and in natural environments can synthesize B12 for absorption as long as there are sufficient amounts of cobalt in the soil where they graze. (Non-ruminant herbivores such as elephants get B12 from dirt and fecal matter ingested with the grass and forage they consume.) Chickens and other birds take in B12 from soil and insects. B12 is then stored in the livers and muscles of these animals, and some passes into their milk and eggs. In the wild, carnivorous and omnivorous animals can thus get B12 by eating other animals. Modern farmed animals, however, do not consume a natural diet; most farmed animals are confined for some or all of their lives and receive supplemental B12 or cobalt in their feed. (3, 4) (Cobalt is the element necessary for ruminant B12 synthesis, and cobalt supplementation of all ruminant diets throughout the US is currently recommended). In fact, most of the world’s synthetic B12 (55-90% depending on the source) is consumed by farmed animals. (5, 6) Even organic and pastured animals receive supplemental B12 or cobalt. This means that in industrialized societies, most meat, eggs and dairy are not any more “natural” as sources of B12 than the fortified foods or supplements vegans consume. In both cases, the B12 derives from a synthetic supplement.

Is drinking the breast milk of another animal more natural than taking a B12 supplement?

The question of whether or not supplemental B12 is “natural” seems to be the wrong question. Is taking aspirin for a headache natural? Is medicine natural? What about other vitamin supplements, like vitamin D? More than 1 billion people globally are vitamin D deficient, with people limiting their sun exposure to protect from skin cancer, and with the patterns of modern life meaning much of the world’s population spends a majority of time indoors. Additionally, some populations live in low sunlight areas. Should those people not take a vitamin D supplement?

B12 in dairy products

Dairy calves are taken from their mothers within hours of birth. Males are sold at auction to be killed for veal or cheap beef. Photo: Compassion over Killing

Those who insist that veganism is not natural because of the need to supplement with B12 ought to consider whether there is anything natural about our practice of artificially breeding and genetically manipulating billions of animals in order to confine and kill them. And could there be anything less natural than forcibly impregnating females of another species and stealing and killing their babies in order to drink the breast milk intended for them?

But more important than whether or not these practices can be considered “natural” is whether or not they are ethical. When we shift the question from what is natural to what is ethical, we can easily clear up questions of what we ought to do. Is it ethical to breed sentient individuals into existence for the sole purpose of killing them for flesh and secretions we have no need to consume? Is it ethical to forcibly inseminate female animals and destroy their motherhood and babies so we can make ice cream out of their breast milk? Of course not.

B12 supplements are recommended for everyone over the age of 50.

If supplementing with B12 helps us to easily eliminate harming and killing billions of animals, then why not go vegan and take a B12 supplement? Especially when it is already recommended that everyone over the age of 50 take a B12 supplement (see the US Dietary Guidelines). This is because most cases of B12 deficiency have nothing to do with diet; rather, they arise as a result of gastric atrophy, which leads to a reduced ability to absorb B12 from foods. (7) Roughly 1 in 100 people will develop B12 deficiency from gastric atrophy by the age of 60. (8)

Synthetic B12 is better absorbed than B12 from most animal foods.

Even the USDA recommends the synthetic supplement form of B12, noting that it is better absorbed than B12 from animal products. The USDA is the largest proponent of animal agriculture in America. The following is taken from their nutrition.gov website:

People over age 50 should consume vitamin B12 in its crystalline form, that is, from fortified foods (like some fortified breakfast cereals) or as a supplement.

Note that older adults often have a reduced ability to absorb vitamin B12 from foods. However, crystalline vitamin B12, the type of vitamin B12 used in supplements and in fortified foods, is much more easily absorbed.

Vegan foods fortified with B12

b12 fortified non-dairy milks

Many non-dairy milks are fortified with B12. Image courtesy of Vegan Street

In addition to multivitamins and B12 supplements, many breakfast cereals, non-dairy milks, granola bars and vegan meat products are fortified with B12; simply check the nutrition panel on the package to see if B12 is included. The following foods are reliable sources of the recommended daily intake of B12:

  • 1 cup fortified soymilk or other B12 fortified non-dairy milk
  • 1 oz. fortified breakfast cereal (such as Total, Nature’s Path Optimum Power, Kashi, Special K, Cheerios)
  • 1-1/2 oz. fortified meat analog
  • Some nutritional yeast brands (such as Red Star Vegetarian Support Formula)

About 2 rounded teaspoons of large flake Red Star Vegetarian Support Formula nutritional yeast provides the recommended daily amount of vitamin B12 for adults. Nutritional yeast is delicious sprinkled over popcorn, pasta, salads, baked tofu, roasted or sauteed chickpeas, and many other foods. (Cats and dogs love it too!)

It is also easy to meet your RDA of vitamin B12 with a serving of fortified cereal. Here is a list of cereals fortified with B12. Some cereals also contain dairy ingredients, so be sure to check the label.

The easiest and most reliable way to meet your B12 needs is to take a supplement. B12 supplements are inexpensive and several brands are usually available in the vitamin section of stores. Be sure to look for capsules that do not include gelatin in the ingredients list (gelatin is made from animal products).

How much vitamin B12 do I need?

Although the requirements for vitamin B12 are quite low, a vitamin B12 deficiency is a very serious problem that can eventually lead to anemia and irreversible nerve damage. It is recommended that adults consume 2.4 micrograms (mcg) of B12 per day. Pregnant women should get 2.6 mcg, and lactating women should consume 2.8 mcg. Consuming high amounts of B12 has not been shown to be harmful.

Leading public health experts and government advisory boards all over the globe now agree that a well-planned vegan diet is a safe, healthy and viable option for all age groups, and that eating plant foods instead of animal-based foods can confer significant health benefits, including reduction in incidence of obesity, diabetes, high blood pressure, high cholesterol, heart attack, stroke, and some types of cancer. To learn more about vegan nutrition, see our feature: Vegan Diets: Sorting Through the Nutritional Myths.

Further reading: Catching Up With Science: Burying the “Humans Need Meat” Argument, and A Vegan Doctor Addresses the Protein Question


(1) Victor Herbert (1988). “Vitamin B-12: plant sources, requirements, and assay.” American Journal of Clinical Nutrition 48 (3 Suppl): 852–8.

(2) ibid.

(3) Stewart, Lawton. “Mineral Supplements for Beef Cattle.” http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=7650

(4) Poultry News, Vitamin B12 Supplementation http://www.poultrynews.com/New/Diseases/Merks/207022.htm

(5) Bruno Kaesler (2005), “Vitamins: 9. Vitamin B12 (Cyanocobalamins)”, Ullmann’s Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH

(6) Dr. Jennifer Rooke, Do Meat-Eaters Need Vitamin B12 Supplements?

(7) Physicians’ Committee for Responsible Medicine, Don’t Forget Your Vitamin B12


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About Ashley Capps



  1. Pingback: 12 ok, hogy vegánok legyünk! (Informatív) | New Start Vegan

  2. Thanks Ashley, great article. I agree completely with your comments on the question of what is natural, and have previously written, in relation to B12, that (a) destroying rainforests and other natural environs; and (b) operating industrial farming systems; purely for animal food products, is hardly natural. Sadly, in Australia, fortification of food products is not permitted to the same extent as in the USA. The Medical Journal of Australia has reported: “In contrast to the United States, where foods are extensively fortified with vitamin B12, Food Standards Australia New Zealand permits only a limited number of foods to be fortified with vitamin B12. This includes selected soy milks, yeast spread, and vegetarian meat analogues such as soy-based burgers and sausages.” (Zeuschner, C.L. et al., “Vitamin B12 and vegetarian diets”, MJA Open 2012; 1 Suppl 2: 27-32, 4 June 2012, https://www.mja.com.au/open/2012/1/2/vitamin-b12-and-vegetarian-diets)

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