Vitamin B-12 for Vegans: What You Need to Know

Vitamin B-12 for Vegans: What You Need to Know

While going vegan and eating a plant-based diet is a smart move when it comes to helping animals, the planet and our bodies, we need to make sure we cover all of our nutritional bases. If you’re eating a well-balanced diet of colorful plant foods including whole grains, legumes such as beans, lentils and peas, nuts and seeds, vegetables including dark leafy greens, and fruits, you’re likely getting most of the nutrients you need. 

The Basics of Vitamin B12 

There is just one nutrient that isn’t available naturally in plant foods and that is vitamin B12. Vitamin B12 is produced in the digestive tracts of mammals, which is why it is found in animal foods such as meat, eggs and milk.

We need vitamin B12 for proper neurological functioning and red blood cell production. Vitamin B12 is also required for the synthesis of DNA and RNA.

Consuming, Digesting and Absorbing Vitamin B12

We require adequate stomach acid as well as something called intrinsic factor in order to digest and absorb vitamin B12. Some people don’t have strong stomach acid or enough intrinsic factor, which is why more than just vegans may need to supplement with vitamin B12.

You may have heard some myths about vitamin B12 such as being able to obtain it from unwashed produce, fermented foods or sea vegetables, and that simply isn’t true. Sea vegetables contain inactive analogs of vitamin B12 that can actually interfere with the absorption of active forms of the nutrient.

Others proclaim that we make our own vitamin B12 just like others animals do, but the issue is that vitamin B12 is absorbed higher up in the digestive tract than where it is made. In other words, any vitamin B12 we make, we poop out.

The only reliable sources of vitamin B12 in a vegan diet are fortified foods and supplements.

Because the body has the ability to store vitamin B12 for a few years, a vegan may consume inadequate amounts of the nutrient without realizing the effects for some time. By the time you notice the signs of a vitamin B12 deficiency, some irreversible neurological damage may have been done. Symptoms of vitamin B12 deficiency include anemia, weakness and weight loss as well as memory loss and numbness or tingling in the extremities.

Research shows that vegans and raw foodists commonly suffer from vitamin B12 deficiency, with estimates up to 70% in some populations.

It’s not worth it to wait around and see if you get a nutritional deficiency—when it comes to vitamin B12, it’s best for vegans to supplement or eat fortified foods as soon as they go vegan.

Vitamin B12 Recommendations for Vegans

Luckily, consuming adequate vitamin B12 is very easy to do. The recommended dietary allowance for vitamin B12 is 2.4 micrograms per day for adults. Fortified foods are easily accessible and vitamin B12 supplements are very affordable. Absorption of this nutrient decreases as the dose increases, so registered dietitian nutritionist and vegan nutrition expert Ginny Messina recommends one of the following:

  • Fortified foods with 2 – 3.5 micrograms of vitamin B12 twice per day
  • Supplement with 25 – 100 micrograms of vitamin B12 daily
  • Supplement with 1000 micrograms of vitamin B12 once per week

If relying on fortified foods, be sure to read the nutrition facts label to determine the amount as not all vegan products nor nutritional yeast are fortified with vitamin B12. If you have concerns about your vitamin B12 status, ask your doctor for a blood test and work with a registered dietitian nutritionist to develop an individualized nutrition plan. You can find RDNs with vegetarian nutrition expertise by searching here.

Additional Information:

The Vegan RD, by Ginny Messina, MPH, RD
Vitamin B12: A Vegan Nutrition Primer
Finding the Best Vegan Vitamin B12 Supplement
Vitamin B12 Supplements: How Much is Enough?
Vitamin B12 and D: Monitoring versus Supplementing by Jack Norris, RD
Vitamin B12: Are You Getting It?
Vegan Sources of Vitamin B12

Vegetarian Nutrition Dietetic Practice Group
RD Resources for Consumers: Vitamin B12 in Vegetarian Diets

Research Studies:
Health effects of vegan diets
Hygienic Assessment of Nutrition in Vegetarians and People with Mixed Feeding
The impact of vegan diet on B12 status in healthy omnivores: five-year prospective study
Vegan Diet, Subnormal Vitamin B12 Status and Cardiovascular Health

Disclaimer: The information presented here is not to be construed as medical advice or used to diagnose, treat, cure or prevent any condition or disease.

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