Why Lack Of Vitamin B12 Kills: What Vegans Urgently Need to Know [2023 Update]

vitamin b12, tablets, pills

There’s one infamous nutrient for vegans that needs special attention: Vitamin B12.

Vitamin B12 deficiency is incredibly serious. If you fail to get adequate intake of Vitamin B12 long enough, you can end up with devastating symptoms. Paralysis [1], psychosis [2], blindness [3], and even death [4] – were all reported in the current body of evidence.

Therefore, understanding Vitamin B12 is of urgent and primary importance in a vegan diet. (Not unlike iron, which is another essential nutrient us vegans need to pay special attention to: https://fitvegans.com/vegan-iron-sources)

As an award-wining personal trainer, published author and ethical vegan of 8 years – I’ll outline in this ultimate guide:

  • What Vitamin B12 is (and how to avoid its deficiency)
  • How Vitamin B12 deficiency manifests itself (including early symptoms which you may or may not be suffering from right now)
  • The best sources of Vitamin B12 (supplements, fortified foods, or things such as nutritional yeast?)

Here’s my promise to you: If you read through this article, you’ll learn enough about Vitamin B12 to never ever worry about the lack of it again.

Ready? Let’s dive in:

hands, macro, plant

1. Vitamin B12 Basics

Contrary to popular belief, Vitamin B12 is not produced by animals. It’s produced by micro-organisms. Specifically, micro-organisms that live in the soil and intestines of certain animals. [5]

1.1 Why is vitamin b12 not vegan?

That’s the first fallacy most people have. B12 is actually vegan. As again, it’s produced by micr-organisms.

Cobalt (vitamin B12) deficiency has been identified in some animals, including sheep, goat, and cattle. Animals raised in areas where cobalt is scarce show reduced food intake and growth retardation. This problem has been recognized by dairy farmers. [6]

That’s why, some farmers, in cobalt-depleted soil, supplement their farm animals with Vitamin B12.

1.2 Can vegans get vitamin B12 naturally?

Scientific evidence indicates that we indeed, used to get Vitamin B12 naturally. The amount hypothesized to be in water, dirt (or feces) our ancestors ate – seems to be enough to hit the recommended dietary allowance (RDA). [7]

So yes, we very much used to get B12 ‘naturally’ – the question is: Was this a good thing?

Because we live in a very modern and sanitized world, we now chlorinate the water supply to kill off any micro-organism. This is not a ‘conspiracy’ by the government to subdue us peasants, as some gurus may want you to believe. The sanitation of the water supply was done to reduce us suffering from the cholera disease. [6] Now, that’s a good thing.

While the sanitation is obviously a net positive, it’s still somehow a double-edge sword. Not dissimilar to Vitamin D (the sunlight vitamin):

  • Yes, living in houses gave us the opportunity to shelter us from the climate.
  • Yet, being sheltered from sunlight also made us deficient in Vitamin D.

Again, living in houses is a net positive. But there are a few downsides to living in houses, such as a lack of sunlight on our skin. Which will lead to Vitamin D deficiency.

We live in modern times. And modern times, need modern solutions.

1.1 Do vegans actually need vitamin B12?

In short: Yes. Unequivocally, all vegan doctors agree that Vitamin B12 is absolutely and definitely an essential vitamin. [7]

Dr. John McDougall M.D., calls Vitamin B12 in his legendary book ‘The Starch Solution’ as being ‘the only exception’. I

Vitamin B12 is one of eight B vitamins. It is required for DNA synthesis. [8] It is important in the normal functioning on the nervous system, as it synthesizes myelin (the yellow thing that makes sure that nerve signals transmit properly). [9] And it is mportant for the formation of red blood cells in the bone marrow. [10]

1.2 Do vegans get vitamin B12 deficiency?

Yes, and Vitamin B12 deficiency is very common. According to a study called ‘How prevalent is vitamin B12 deficiency among vegetarians [and vegans]?’ [11]

“The deficiency rates reported for specific populations were as follows: 62% among pregnant women, between 25%-86% among children, 21–41% among adolescents, and 11–90% among the elderly.”

So yes, we vegans get B12 deficient. And vegans that do not pay special attention to Vitamin B12 do so quite often.

nerve cells, neurons, nervous system

2. Vitamin B12 Deficiency

Because Vitamin B12 is responsible for a variety of different functions in the body, Vitamin B12 deficiency comes in many different shapes and forms.

The following deficiency symptoms are sorted by rapidity of onset. The first symptoms we’re covering in this chapter are usually the earliest symptoms of Vitamin B12 deficiency. The latest symptoms are delayed symptoms of Vitamin B12 deficiency.

2.3 Vitamin B12 And Cobalamin Neuropathy (Neurological disorders due to cobalamin deficiency)

Dr. John McDougall MD, in his Starch Solution book, wrote:

“The most common nervous system symptoms of B12 deficiency are numbess and tingling in the hands and feet.”

Dr. McDougall was talking about ‘Cobalamin Neuropathy’. For the non-doctors here, ‘Cobalamin’ stands for ‘Vitamin B12’ – and ‘Neuropathy’ stands for ‘Disease of the Nerve’ (neurological disorders).

Specifically, disease or abnormality of the peripheral nervous system. So not central (brain, or spinal cord), but peripheral: Hands and feet.

While these symptos are completely reversible at earlier stages, at later stages, they are not. THe nerve damage is permanent. And the accompanied symptoms of nerve damage persist.

The symptoms seem to be caused by impaired transmethylation. [12] In plain English, this means that the chemical compound ‘homocysteine’ can not be turned into ‘methionine’. Because for ‘homocysteine’ to turn into ‘methionine’, adequate levels of Vitamin B12 and folate need to be in the body.

That’s why one way to test for Vitamin B12 deficiency is to see if there are elevated ‘homocysteine’ levels in the blood. Some health professionals go so far and claim that this is an even better diagnosis of B12 deficiency, than serum cobalamin levels. [13]

High homocysteine levels are especially dangerous if they’re combined with the next symptoms:

blood, cells, red

2.4 Vitamin B12 And Pernicious Anemia (or: Megaloblastic Anemia)

Megaloblastic anemia (formerly ‘pernicious anemia’) stands for ‘megaloblasts’ = large precursors of red blood cells, and ‘anemia’ = ‘lack of’. [14]

So the red blood cells in a person with Vitamin B12 deficiency are unusually large (because they’re not properly created), and unusually few.

Because the blood cells are responsible for adequate transmission of oxygen – and other things such as glucose – the patients that suffer from megaloblastic anemia are unusually tired. They’re also unusually pale (as this indicates a lack of blood flow to the face).

These symptoms are identical to iron-deficiency anemia. Which leads to a lack of red blood cell production, just without the giant red blood cells that one usually sees in Vitamin B12 deficiency. [15]

This is why it’s so important to be aware that Vitamin B12 deficiency can cause anemia. Because if you are not aware of this link, your doctor will prescribe you iron pills for your anemia (because iron-deficiency is significantly more common than megaloblastic anemia).

The cause of the giant blood cells is that B12 deficiency impairs DNA synthesis.

2.5 Vitamin B12 And Hyperhomocysteinemia (Homocysteine connection)

The lack of Vitamin B12 can lead to elevated homocysteine levels in the blood. This happens because of the mechanism we talked about before.

Remember the transmethylation thingy? Yep…

… so, not enough Vitamin B12 will prevent homocysteine from changing to methionine. And as such, homocysteine levels will be markedly increased in the blood test.

This is a problem. Scientific evidence indicates that increased homoycsteine levels are a potential risk factor for cardiovascular disease, schizophrenia [16], Alzheimer’s disease [17], and osteoporosis [18].

Adequate intake of both folic acid, and Vitamin B12 is required to guarantee low levels of homocysteine. It should be noted that lowering of homocysteine by folic acid fortification may not be the solution because it fails to solve the disruption of the methionine cycle due to B 12 dependency.

2.6 Vitamin B12 And Dementia

The current body of evidence suggests that at two stages of life vegans most susceptible to Vitamin B 12 deficiency: In the embryo, and as an elderly individual. [19]

There are two reasons for the phenomena in the elderly:

  1. The symptoms of Vitamin B12 deficiency as an older person is worse. B12 deficiency at this stage is related to increased risk of dementia. [20]
  2. Absorption rates of Vitamin B12 are significantly lower if you’re older.

So not only are you more prone to Vitamin B12 deficiency as an elderly individual, you’re also more prone to serious side effects.

Up to 38% of older adults may exhibit mild vitamin B12 deficiency and depleted vitamin B12 stores [21].

For optimal health, older individuals following a vegan diet need to take in a higher amount of Vitamin B12 (more about this later in this article).

carrots, garden, dirt

3. Sources Of Vitamin B12 In The Omnivore, Vegan and Vegetarian Diet

Now that we know the importance of Vitamin B 12, we need to know where to source it correctly in a vegan diet.

3.1 Getting An Adequate Amount of Vitamin B12

The RDA (recommended dietary allowance) of Vitamin B12 is not much. The most recent recommended intake is 4.5 μg three times per day. And total body stores in adults can exceed 2500 μg. [23]

Often times, it takes years to develop a full-blown B 12 deficiency. It can take less than that to get mild deficiency symptoms (which we eluded to above).

3.2 Where Is Vitamin B12 Normally Found In Animal Foods?

We’ve seen before that micro-organisms are the only organisms capable of vitamin B12 bioynthesis. So micro-organisms are responsible for the presence of B 12 in animal derived foods such as fish, meat, eggs and dairy products.

Out of these animal foods, only eggs and dairy products are part of vegetarian diets.

3.3 How much B12 should a vegetarian take? (vegetarian diets)

Quick heads up for the folks following vegetarian diets: You can technically get your Vitamin B12 from eggs and dairy products. These are the only purely vegetarian sources (next to the vegan sources we outline below).

While B12 is easier to get from eggs and dairy products, please keep top of mind that so is salmonella poisoning [24] and high cholesterol. Even if you’re following a vegetarian diet, you’re better off getting the Vitamin B12 not from animal-derived foods. To put it bluntly: Screw fish and dairy products.

Relying on vegan sources (instead of vegetarian sources) for B12 might seem more daunting. Yet the reality is that this is all a matter of habit.

In fact, some plant based fortified foods have even more B12 than meat foods!

3.4 Can you find vitamin B 12 in a natural vegan diet?

Unlike other vitamins, B12 is not present in natural plant foods.

There are numerous ways to get vitamin b12 though on a plant-based diet. Fortified foods, nutritional yeast – and supplements. Let’s talk about them all in full detail:

3.5 List Of Reliable Vegan Vitamin B12 Sources

The most popular dietary sources of vitamin B12 by vegans are as follows:

Plant-based meats (fortified foods)

Plant-based meat companies are very aware that most vegans are lacking in B12. That’s why many plant-based meats are an ‘okay’ source of B12.

Beyond Meat, for example, has exactly 2.4 μg of VitaminB12 in it’s patty. [25] This is almost 5x more than chicken. [26]

Yet it’d still require 6 servings of Beyond Meat per day to hit the current recommended intake of Vitamin B 12.

Impossible burger contains about ~3.5 μg of Vitamin B12. [27] Again, that would require about 6 servings of burgers per day.

Fortified foods from burgers can be enough if you’re a true junk food vegan – but it’s often not sufficient.

Fortified Soy + Almond Milk (fortified foods, again)

Fortified plant milks are an ‘okay’ source of Vitamin B12.

The fortified soy milk by ‘Silk’ for example has about ~3 μg of Vitamin B12 in it. [28] As such, it will require 6-cups of that soy milk to hit the required daily allowance.

Again, if you’re a soy lover – that is great! Otherwise, you might be better with another option.

Nutritional Yeast

One of the only feasible options to get enough Vitamin B 12 per day is nutritional yeast. If you eat 2 teaspoons 3x per day of nutritional yeast, you hit your recommended dietary allowance.

Doable, but…

… that’s 6 teaspoons.

And some of the nutritional yeast brands out there might not even be fortified.

Fortified foods: Cereals

Some cereals contain vitamin B 12 as well to a degree. But as you might have guessed, it’s to a similar extent as plant milks, nutritional yeast or plant-based meats have.

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