Plant-Based Eaters, Vegetarians, and Vegans Need to Supplement with Vitamin B12

Vegans and vegetarians and B12 status

Over the years, vegetarian and vegan diets have increased in popularity, whether it be for ethical, environmental, or health reasons. According to a 2018 Gallup Poll, approximately 16.4 million people in the United States report being vegetarian, and 3% of the population reports being vegan (eliminating ALL animal-based foods). Are you one of these many people eliminating meat and animal products? If so, read on, as this is very important.

For the millions of people worldwide eating a plant-based diet, vitamin B12 is a nutrient of concern. It is nearly impossible to obtain enough vitamin B12 from plant-based foods to prevent deficiency, and vitamin B12 deficiency is dangerous and can lead to fatigue, constipation, and nerve damage (1). In fact, despite their vegetable-rich eating pattern, a vitamin B12 deficiency can put vegans at greater risk for heart disease through elevation of homocysteine levels (2). Because of this, it is generally recommended that plant-based eaters supplement their diet with vitamin B12.

Let’s get a deeper understanding of this vitamin.

Why You Need Vitamin B12

Functions of Vitamin B12

As you can see in the graphic above, vitamin B12 is important for many different functions in the body, including energy metabolism and the breakdown of carbohydrates and fats. This is why we feel so fatigued when we do not consume sufficient amounts of this vitamin, not to mention the fact that we need it in order to produce serotonin! While vitamin B12 is often thought of as an energy vitamin, it is also responsible for converting homocysteine to methionine. When we don’t have enough vitamin B12 to fuel this conversion, we accumulate too much homocysteine, which can be harmful when elevated. Lastly, we also need vitamin B12 for growth of proteins, as well as for building red blood cells and DNA.

Do You Get Enough Vitamin B12?

If you consider yourself a plant-based eater, you likely will need to supplement with vitamin B12, and here’s why:

The best sources of vitamin B12 are found in animal-based foods. In a brief look through the government database list of the top 20 richest sources of vitamin B12, only two of them are plant-based sources (nutritional yeast and breakfast cereals), and even these only contain vitamin B12 because they are fortified. While many Americans don’t get enough vitamin B12 anyway, it is worsened when you remove animal products from your diet.

Vitamin B12 deficiency or suboptimal intake is VERY common in vegans and vegetarians. As vegetarian and vegan diets lack almost all of our natural sources of vitamin B12, it is not surprising that deficiency is common.

  • In a systematic review, up to 86% of those following a vegan diet were deficient in vitamin B12. (3)
  • In this same study, up to 81% of vegetarians were found to be deficient in vitamin B12.
  • A literature review looking at the prevalence of vitamin B12 deficiency in vegetarians and vegans at different life stages found: (1) up to 86% of children were deficient, (2) 62% of pregnant women were deficient, (3) 21 to 41% of adolescents were deficient, and (4) up to 90% of elderly were deficient. (4)

How to Know If You Need More Vitamin B12

Vitamin B12 deficiency is common in the regular population, and even more common among plant-based eaters. So, the likelihood that you could benefit from supplementing with vitamin B12 is probably higher than you think. Vitamin B12 is water soluble, which means that any excess introduced into the body can be excreted in the urine. So, if you experience any of these symptoms listed below, it would behoove you to try a vitamin B12 supplement.

Signs and Symptoms of Vitamin B12 Inadequacy:

Moderate deficiency

Chronic fatigue


Loss of Appetite


Weight Loss


Severe deficiency


tingling in hands and feet

Poor Memory

Soreness of tongue

Abnormally large red blood cells

Balance problems

Irreversible nerve damage


If you really want to be sure you are deficient before taking a supplement, there are a few options for testing your vitamin B12 levels.

  • Serum B12 will measure the level of vitamin B12 in your blood.
  • MMA, also known as Methylmalonic Acid, is thought to be a more accurate measure of vitamin B12 status than serum B12 as it measures ACTIVE B12. If you don’t have enough vitamin B12, this measure will be elevated. (5)
  • Since vitamin B12 is needed to convert homocysteine to methionine, homocysteine levels will be elevated if you are deficient in vitamin B12. Researchers have reported that this test can detect vitamin B12 deficiency about 95% of the time. (6)

Better Safe Than Sorry

Since we know that a vitamin B12 deficiency is more the rule than the exception in the plant-based population, it is wise to ensure that you obtain plenty of vitamin B12 from diet and supplements combined. A vitamin B12 deficiency can be serious if gone untreated, and it can go unnoticed for a long time as its symptoms tend to be very general when mildly deficient (fatigue, constipation, etc.). Some symptoms of vitamin B12 deficiency are irreversible, including nerve damage. Since this is a water-soluble vitamin, supplementation presents very little risk, and much potential for reward.

What, and How Much?

What: The hydroxocobalamin form of vitamin B12 is optimal, because it is a fully activated form. This means that even if you have low stomach acid (a common barrier to vitamin B12 absorption), you will still reap the full benefits of the supplement. You can also absorb it sublingually, i.e., beneath your tongue. This is one of the reasons hydroxocobalamin is the form used to treat clinical deficiency.

How Much: It is generally recommended to take one 2,000 mcg lozenge (as offered in Rise Well), and adjust upward as needed. This will offer a similar amount to what you would receive in the 1,000 mcg injection commonly given in a clinical setting.



  1. NIH (National Institutes of Health). Vitamin B12: Fact Sheet for Health Professionals. NIH, Office of Dietary Supplements.
  2. Majchrzak, D., et al. 2006. B-vitamin status and concentrations of homocysteine in Austrian omnivores, vegetarians and vegan. Annals of Nutrition & Metabolism 50(6):485-491. Doi: 10.1159/000095828.
  3. Pawlak, R., et al. 2014. The prevalence of cobalamin deficiency among vegetarians assessed by serum vitamin B12: A review of literature. European Journal of Clinical Nutrition 68(5):541–548. Doi:10.1038/ejcn.2014.46.
  4. Pawlak, R., et al. 2013. How prevalent is vitamin B(12) deficiency among vegetarians? Nutrition Reviews 71(2):110-117. Doi: 10.1111/nure.12001.
  5. U.S. National Library of Medicine. Methylmalonic acid (MMA) test. Accessed 29 Nov. 2020.
  6. Gilfix, B. M. 2005. Vitamin B12 and homocysteine. CMAJ 173(11):1360. Doi: 10.1503/cmaj.1050170.