Are vegans and vegetarians at risk of vitamin B12 deficiency?

Don from the comments asks:

I’ve been vegan for over 10 years and the single nutrient that’s not found in vegetarian diets is vitamin B12. Vitamin B12 is created by a biological interaction between microbes and fertile soil, so traditionally people could be vegetarian without being susceptible to anemia. In addition, people used to drink unpasteurized milk which was a good source of B12, but not so for pasteurized milk…….. I’d appreciate your opinions on the subject. Thanks.

The issue of vitamin B12 and the vegan/vegetarian diet is an old canary, and unlike other perceptions of plant based diets, this one has some teeth.

Plant foods are not good sources of vitamin B12, and you sure as hell need it.

So let’s go over what this means if you’re thinking of making the plant-based diet switch. There are some legitimate B12 risks that I’ll address, but it’s important to compare this drawback with the many benefits of being a herbivore.

A Brief Overview of Vitamin B12

Vitamin B12 is an essential micro-nutrient that’s not made by plants or animals. It’s made by bacteria. Animal cells can store the B12 made by bacteria and plants can’t, so animal foods tend to be a good source and plants are not.

A lot of the bacteria in human bodies make vitamin B12, but most of them live in your colon and B12 is digested in your ileum, which is north of your colon. So you literally poop most of it out.

Poop is actually a rich source of vitamin B12, and one of the reasons we haven’t traditionally been B12 deficient is because for most of our history we have lived in close proximity to our animals, and ate vegetables that were grown in soil fertilized by maneur. We’re far separated from those conditions now, which is why vitamin B12 deficiency can creep up from time to time.

What Does Vitamin B12 Do?

Vitamin B12 performs the following functions in your body:

• supports nervous system development and function
• supports red blood cell production
• helps metabolize all food sources (carbohydrate, protein, fat)

If you don’t get enough vitamin B12 you might:

• feel weak/nautious
• lose memory
• experience fevers
• have weird stuff start happening to your tongue
• lose sense of taste/feeling
• experience depression

None of the above stuff sounds like very much fun to me, so it’s best to make sure you get enough vitamin B12 in your diet!

Efficiency

Your body uses vitamin B12 very efficiently. You need about 0.003 g/day, and you can actually get by on about 1/10th that much if you have to.  Your body can actually store vitamin B12 for up to 20 years, and a 3 year supply of vitamin B12 in your liver is common.

For this reason acute B12 deficiency is uncommon even if you’re a vegetarian/vegan.

However, if vitamin B12 is an issue it’s usually not because you’re not receiving it in your diet.

Most Vitamin B12 problems are due to stomach/intestine problems rather than diet deficiency.

Sometimes your stomach will stop making a compound called intrinsic factor that’s essential to digest B12, and sometimes autoimmune disorders and complications from surgeries prevent the ileum from digesting it. These problems trump the prevalence of diet induced B12 deficiency.

However, that still begs the question……

Are Vegans and Vegetarians At Risk For Vitamin B12 Deficiency?

Yes.

Properly planned vegan/vegetarian diets should be fine, but the truth of the matter is a lot of plant eaters get vitamin B12 in sub-optimal amounts.

A good illustration of this point is a study published in the American Journal of Clinical Nutrition that summarized existing research on vitamin B12 and the vegetarian diet. A good summary can be found on this graph here. Vegans and vegetarians regularly have lower plasma levels of B12 than omnivores. Other studies have suggested that as much as 60% of vegetarians have some form of B12 deficiency, and these numbers are especially true for people who don’t take supplements or eat a raw food diet.

So the danger is real, however the issue needs to be put in perspective.

B12 Deficiency vs. Diabetes, Heart Disease, and Cancer

Perhaps I’m being a tad bit groupish, but I think people exaggerate the dangers of  B12 deficiency. It is a serious problem, but an important fact is often overlooked:

Vegetarians and vegans with B12 deficiency often have a variety of other nutrient deficiences as well. 

Or in other words, the people with B12 deficiency are that way primarily because they’re not very good at taking care of themselves, not because they’re vegans.

If you still don’t get my drift, consider the following points:

• The chances of irreversible B12 deficiency in vegetarians is about 1 in 5,000 over the course of your life
• The chances of dying from a heart attack or stroke are about 1 in 2
• The chances of contracting breast cancer for women is about 1 in 7 over the course of her lifetime
• The chances of contracting prostate cancer for men is about 1 in 6 over the course of our lifetimes

Similar discrepancies exist for conditions like osteoperosis, diabetes, hypertension, etc.

The truth is, I think it’s very instinctive to guard your eating habits because it reflects in who you are as a person. So people who aren’t “on your side” are quick to cling to any evidence that justifies their bad habits.

That doesn’t negate the problem, but it does explain the cacophony from the opposition.

Are There Vegetarian Food Sources for Vitamin B12?

There are, but none of them are very good.

Like I said before, plants don’t store vitamin B12 and it’s only made from bacteria. So potential food sources include:

• fermented vegetables (sauerkraut, tempeh, korean laver)
• nori (a seaweed)
• spirulina, other freshwater algaes

But do yourself a favor and don’t rely on any of these exclusively.

It helps that a lot of vegan/vegetarian foods are fortified with B12, and that’s often enough to keep you above water.

However, it’s a good idea to take a supplement.

B12 Supplements

B12 supplements are cheap, and actually contain way more B12 than you actually need. 5mcg a day is more than enough, but typical dosages usually range from 100 to 5000 mcg per pill.

Regarding this issue, I’d make two points:

• Supplementation is usually enough to shield you from dangers of B12 deficiency
• Eating a diet rich in probiotics helps

Advice for Taking B12 Supplements

When taking a B12 supplement, I’d be careful of the following points:

• make sure methylcobalamin is the active ingredient. It’s the form of B12 that’s most readily digested. (Methyl cobalimin is very common)
• it’s better to chew or dissolve B12 pills than swallowing them outright
• other vitamins reduce the bioavailibility of B12, so buy a B12 vitamin separately.