Are you getting enough B12? Anyone eating a plant-based diet has surely been the recipient of this question. No matter what your diet looks like, it’s important to know the answer.

Although vitamin B12 is only needed in trace amounts, it is necessary to consume it in your diet. Unlike many other vitamins, the body does not produce B12. Most people get their B12 from consuming animal products (along with the fat, cholesterol, and all the other stuff they contain).

Why B12 is important.

Why is B12 a necessary part of our diet? For starters, a deficiency in this vitamin leads to what is called pernicious anemia. “Pernicious” because it is irreversibly destructive to nerve and brain cells, and “anemia” because it affects your blood. A lack of B12 prevents your cells from dividing properly, causing megaloblastic (ie: gigantic) red blood cells. B12 is required to make DNA, which is a necessary tool for cell division to even occur; without B12 cells can’t divide and will become large.

Your nerve cells also need B12. B12 is necessary to keep the myelin sheath functioning properly, allowing for rapid communication in your body. Without B12, nerve cells can become damaged beyond repair affecting feeling in your limbs and brain function. The vitamin also serves a critical function in developing the central nervous system, and studies have shown that a lack of it can cause a decrease in brain development and brain function in infants.1

How we can get enough B12.

For people free of gastric health problems, there are healthy food sources for B12. Plant sources with naturally occurring B12 include some fermented soy products such as tempeh and miso,2 and also some seaweeds. Since natural levels of B12 can vary, particularly in seaweed, a good way to ensure you are getting sufficient B12 is to consume plant foods fortified with B12. These foods include many dairy alternatives for milk and cheese (such as soy/almond/rice milk).

Nutritional labels will list whether or not there is B12 in a given product and it will also be included in the ingredients list. Another great food source is nutritional yeast flakes, but make sure it is actually fortified with B12. These inactive yeast flakes add a slightly cheesy flavor and can easily be added to any dish you’re making – from soups to spreads, “cheese” dips to popcorn. It’s delicious!

Although the above foods are good sources of B12, most Americans continue to get their B12 from animal products. This leads us to an interesting question: “Where do the animals (at least the plant-eating variety) get their B12?”. As it turns out, B12 is produced by soil microbes located in plant roots!3 This means our ancestors were able to get the B12 they needed from vegetables (more specifically, the trace amounts of dirt left on their vegetables). Unfortunately, because of the pollution in our environment, plants now need a good scrubbing before consumption to remove potentially harmful components. A side effect of the cleaning process is the loss of most, if not all, of a plant’s B12 content. This is why we recommend getting B12 through fortified plant-food sources in your diet.

While it is important to ensure an adequate source of B12, don’t worry too much about missing a day. Your body is able to store several years worth of B12 in your liver4 and does a great job of recycling it for use.5 That being said, it’s hard to store several years’ worth of B12 if you do not consume enough to start with. There are no known adverse effects of consuming too much; so it’s a good idea to be safe, rather than sorry.

How to avoid B12 deficiency?

The groups at greatest risk of vitamin B12 deficiency include: seniors, those with Crohn’s disease, celiac disease, gastritis Type A or B, vegans, vegetarians, those who are pregnant, people taking acid blockers, or anyone who has had surgery to remove or block portions of the stomach or small intestine.

When B12 is consumed, it is bound to protein in your food. However, once it reaches the small intestine, stomach acid splits vitamin B12 from its protein carrier so that it can be linked with a glycoprotein called intrinsic factor (IF). At this point, it migrates to the bloodstream for use by the body.

With age, the stomach begins to produce less and less intrinsic factor, which keeps the older population from being able to physically absorb B12. Those with Crohn’s or celiac disease, gastritis type A or B, those taking stomach acid reducers, or those who have had surgery involving their stomach or small intestine, are all at risk of reduced, or eliminated, stomach acid production, meaning that the body cannot break apart B12 for absorption (even if it is prevalent in your diet).

The main risk for vegans or vegetarians is not consuming sufficient B12 in their diet. For anyone on a plant-based diet, the need to clean food well reduces or eliminates B12. In addition, ovo-lacto vegetarians are often deficient because dairy and eggs are not high sources of B12. Pregnant women, and especially those who may become pregnant, need to ensure they have a good supply of B12.

Those who fit into any of the above-mentioned at-risk categories may consider getting a B12 test from their doctor in order to determine if they have sufficient levels. For those whose stomach acid levels have been affected (either by age, disease, medication, or surgery) it is necessary to consume purified forms of vitamin B12. Purified forms of B12 do not require stomach acid to break the B12 from off the protein—because it is purified, it is already available for the body to use. B12 injections can also be received by a doctor for immediate remedy of a B12 deficiency, but for most cases, a B12 supplement or fortified food is sufficient.

Closing thoughts

Although getting B12 in a plant-based diet is not hard (if you eat products supplemented with B12), the lack of natural B12 in plant foods has caused many to doubt the efficacy of vegetarian or vegan diets. They ask the question: “If a plant-based diet is so good for you, why is there risk for deficiency of this vitamin?”

As we mentioned earlier, B12 is produced by microbes in the soil. In the past, people didn’t wash (or peel) their vegetables as thoroughly as we do today, meaning they would get enough B12 by simply eating their vegetables. Today, we live in a less than perfect world full of pollution and chemicals and therefore (when we clean our vegetables) wash our B12 away. Although B12 is now harder to come by naturally, a plant-based diet fortified in B12 is still a far better option than the typical westernized diet that obtains its B12 from animal products. In effect, they are getting their B12 served as a side of heart attacks, diabetes, and a long list of other ills.

 

References

  1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3137939/
  2. http://www.health.harvard.edu/fhg/updates/update0406d.shtml
  3. http://web.mit.edu/newsoffice/2007/b12.html
  4. http://www.mayoclinic.com/health/vitamin-B12/NS_patient-vitaminb12
  5. http://www.health.harvard.edu/fhg/updates/update0406d.shtml


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Desiree Kröper

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