Menu
  1. Home»
  2. Essential Nutrients»
  3. Vitamins»
  4. Vitamin B12»
NutriSavvy_Know_Your_Food_Options_Banner

The number one nutrient anyone following a plant-based diet should pay special attention to is vitamin B12. Why? Because we can’t get proper amounts of vitamin B12 through whole-foods, plant-based sources. Therefor, the only way to ensure we’re getting what we need is by consciously eating fortified foods or by taking a supplement regularly.

Vitamin B12 is important for the production of our DNA and our red blood cells. We also need it for cell metabolism (converting nutrients into energy) and it is essential for our brain and for the production of various brain chemicals, including serotonin.

While animal-based products do contain vitamin B12, animals do not actually make vitamin B12. This nutrient is made by bacteria! In the past, we would’ve gotten our B12 supply from drinking water with this bacteria or even plants. However, things are sanitized today to avoid harmful pathogens, thus eliminating our natural, animal-free supply of B12. As with other nutrients, when choosing a source we should also consider the full package. Animal-based products lead to heart and circulatory issues, brain health issues, diabetes type 2, cancer, inflammation, and more. For this reason, we do not recommend getting your vitamin B12 from animal-based foods.

Vitamin B12 Absorption

For us to absorb vitamin B12 we need a stomach protein named intrinsic factor. We typically absorb 56% of 1 mcg of B12. The higher the amount we take, the lower the absorption percentage is, due to the availability of intrinsic factor in our bodies at the time of ingestion. If we take a 500 mcg supplement, for example, we only absorb about 10 mcg. This explains why supplements have such high amounts of vitamin B12 when the Daily Value is only 2.4 mcg.

The time when we take our supplements also affects absorption rate. We have more intrinsic factor on an empty stomach than after we eat. Therefor, the recommendation is to take our B12 supplement first thing in the morning. If you are getting your vitamin B12 through fortified foods, you should ingest them twice a day to allow your body to build more intrinsic factor between meals, since we can only absorb about 50% of the vitamin B12 content at a time.

We don’t need to ingest vitamin B12 every day. Our liver can store about 50% of the total B12 we absorb. Therefor, you may choose to take a supplement once or twice a week instead of taking a supplement or consuming fortified foods every day. See calculator below for recommendations based on your age and whether you are pregnant or breastfeeding.

Top Sources For Plant-Based Diets

Unfortunately, there are no bio-available whole-foods, plant-based sources of vitamin B12. Since this nutrient comes from bacteria, and our water system is now sanitized to avoid harmful pathogens, those of us following a plant-based diet can only get it through fortified foods or supplements.

Vitamin B12 Supplements

Vitamin B12 Supplements

See calculator below for dosage amount and frequency.

Fortified Nutritional Yeast

Fortified Nutritional Yeast

2 Tbs may have 2.4 mcg, but only about 50% is absorbed.

Fortified Plant-Based Milk

Fortified Plant-Based Milk

1 cup could have 2.1 mcg but only about 50% is absorbed.

Fortified Cereal

Fortified Cereal

1 serving may have 2.4 mcg but only about 50% is absorbed.

Vitamin B12 Personalized Calculator

See how much vitamin B12 you and your family members need, according to the Dietary Guidelines for Americans, 2020-2025.

Terminology:

  • Daily Value (DV): The recommended amount of nutrients to consume each day for individuals who are 4 years old or older.
  • Recommended Daily Allowance (RDA): The recommended amount of nutrients to consume each day according to the individual’s age, gender, and whether a woman is pregnant or breastfeeding.
  • Upper Intake Level (UL): The highest amount of nutrient intake that will not pose adverse health effects on most individuals.

* The amounts provided by source and frequency are based on the recommendations by Shah, R. and Davis, B. (2020). Nourish: The Definitive Plant-Based Nutrition Guide for Families. Table 5.1. Health Communications, Inc.

Keep in mind that the average vitamin B12 absorption is 56% of 1 mcg of B12. This explains why we should aim at ingesting twice the amount we need through fortified foods. The higher the amount of B12 we take, the lower the absorption percentage is, due to the availability of intrinsic factor (the protein we use to absorb vitamin B12) in our bodies at the time of intake. If we take 500 mcg, we will absorb about 10 mcg. This is why supplements have such high doses.

How Our Body Uses Vitamin B12

Hover over each pointer below for more details on how our body uses vitamin B12. Click on the pointer to visit the specific body part’s interactive page to discover what other nutrients support it, the best sources to find them, and other interesting facts.

B12-Asain-man-golf_800
Be NutriSavvy

Important Things to Know

Hover over each of the interesting facts below to flip the tiles and learn more details.

Check out the interesting facts below! Tap on the red triangles to flip the tiles and learn more details.

We absorb vitamin B12 better on an empty stomach.

We absorb vitamin B12 through a stomach protein named intrinsic factor. We have more of this protein in the morning, before we eat. This is why we’re able to absorb more on an empty stomach. If we don’t take our supplements in the morning, the recommendation is to take them four hours after our last meal. 

Our liver can store vitamin B12 for up to 5 years.

The liver stores approximately 50 percent of the vitamin B12 we absorb. Someone switching to a plant-based diet without supplementing their B12 may not show signs of deficiency for up to 5 years!

Everyone is different, though, so make sure you are taking a reliable source of vitamin B12 if you are on a plant-based diet. If you switched to plant-based in the past few years and you didn’t know you had to supplement your B12, get started right away because you may be running out of your reserves.

Cyanocobalamin is more stable than Methylcobalamin.

Methylcobalamin and cyanocobalamin are the two most common forms of vitamin B12 supplementation. While methylcobalamin resembles the vitamin B12 circulating in our body, this doesn’t make it the best choice because it is highly unstable and susceptible to being destroyed by light. The bottles may be dark, but how exposed were the pills before getting into the bottles or when we take them?

Cyanocobalamin is more stable, which is why it’s the form used in fortified foods. It is also the best option to correct a vitamin B12 deficiency, an it doesn’t need to be an intramuscular dose. Simply chewing a 1000 or 2000 mcg a day tablet (depending on deficiency) or taking a liquid supplement has had great results.

Our body transforms cyanocobalamin into the B12 form it needs, unless you have impaired kidney function. In that case, methylcobalamin is better but at higher doses to make up for potential damage caused by light exposure. Learn more.

Some seaweed contains vitamin B12, but amounts vary too much.

Some seaweed and algae contain vitamin B12, however, most have B12 analogues that can actually block our B12 receptors promoting B12 deficiency. Those that do contain B12, like nori, vary in amounts tremendously, making it impossible to rely on it as a source.

A study found that 4 g (about 14 small sheets of nori) could provide 2.4 mcg a day. That’s a lot of nori every day! But again, even if we loved eating nori snacks or vegan sushi daily, there is no guarantee that this amount is the same in the nori we get at the store or even from one pack to the next.

Multivitamins may turn vitamin B12 into its evil, analogue version.

Taking our vitamin B12 through a multivitamin may actually cause or enhance a vitamin B12 deficiency. This is because other nutrients in the multivitamin supplement like vitamin C, copper, and vitamin B1 can break vitamin B12 and turn it into an analogue B12, which is basically a B12 impostor (also highly present in seaweed and algae).

Analogue B12 is absorbed by our B12 receptors, blocking the entrance of real B12. So, not only would we not be getting B12 from our multivitamin supplements, we’d also be blocking the absorption from other sources such as fortified foods.

So, make sure you take your vitamin B12 supplement separately, ideally, on an empty stomach.

Vitamin B12 deficiency is linked to mood disorders, OCD, and more.

We need vitamin B12 to produce neurotransmitters like serotonin and dopamine. For this reason, a vitamin B12 deficiency can lead to mood, sleeping, and psychiatric disorders including Obsessive Compulsive Disorder or OCD.

Usually anemia precedes these disorders when they are a result of vitamin B12 deficiency. So, it’s easy to get it diagnosed and treated. However, there have been cases when psychiatric disorders come first, like this OCD case in a 29-year-old woman.

 

We absorb vitamin B12 better on an empty stomach.

We absorb vitamin B12 through a stomach protein named intrinsic factor. We have more of this protein in the morning, before we eat. This is why we’re able to absorb more on an empty stomach. If we don’t take our supplements in the morning, the recommendation is to take them four hours after our last meal. 

Our liver can store vitamin B12 for up to 5 years.

The liver stores approximately 50 percent of the vitamin B12 we absorb. Someone switching to a plant-based diet without supplementing their B12 may not show signs of deficiency for up to 5 years!

Everyone is different, though, so make sure you are taking a reliable source of vitamin B12 if you are on a plant-based diet. If you switched to plant-based in the past few years and you didn’t know you had to supplement your B12, get started right away because you may be running out of your reserves.

Cyanocobalamin is more stable than Methylcobalamin.

Methylcobalamin and cyanocobalamin are the two most common forms of vitamin B12 supplementation. While methylcobalamin resembles the vitamin B12 circulating in our body, this doesn’t make it the best choice because it is highly unstable and susceptible to being destroyed by light. The bottles may be dark, but how exposed were the pills before getting into the bottles or when we take them?

Cyanocobalamin is more stable, which is why it’s the form used in fortified foods. It is also the best option to correct a vitamin B12 deficiency, an it doesn’t need to be an intramuscular dose. Simply chewing a 1000 or 2000 mcg a day tablet (depending on deficiency) or taking a liquid supplement has had great results.

Our body transforms cyanocobalamin into the B12 form it needs, unless you have impaired kidney function. In that case, methylcobalamin is better but at higher doses to make up for potential damage caused by light exposure. Learn more.

Some seaweed contains vitamin B12, but amounts vary too much.

Some seaweed and algae contain vitamin B12, however, most have B12 analogues that can actually block our B12 receptors promoting B12 deficiency. Those that do contain B12, like nori, vary in amounts tremendously, making it impossible to rely on it as a source.

A study found that 4 g (about 14 small sheets of nori) could provide 2.4 mcg a day. That’s a lot of nori every day! But again, even if we loved eating nori snacks or vegan sushi daily, there is no guarantee that this amount is the same in the nori we get at the store or even from one pack to the next.

Multivitamins may turn vitamin B12 into its evil, analogue version.

Taking our vitamin B12 through a multivitamin may actually cause or enhance a vitamin B12 deficiency. This is because other nutrients in the multivitamin supplement like vitamin C, copper, and vitamin B1 can break vitamin B12 and turn it into an analogue B12, which is basically a B12 impostor (also highly present in seaweed and algae).

Analogue B12 is absorbed by our B12 receptors, blocking the entrance of real B12. So, not only would we not be getting B12 from our multivitamin supplements, we’d also be blocking the absorption from other sources such as fortified foods.

So, make sure you take your vitamin B12 supplement separately, ideally, on an empty stomach.

Vitamin B12 deficiency is linked to mood disorders, OCD, and more.

We need vitamin B12 to produce neurotransmitters like serotonin and dopamine. For this reason, a vitamin B12 deficiency can lead to mood, sleeping, and psychiatric disorders including Obsessive Compulsive Disorder or OCD.

Usually anemia precedes these disorders when they are a result of vitamin B12 deficiency. So, it’s easy to get it diagnosed and treated. However, there have been cases when psychiatric disorders come first, like this OCD case in a 29-year-old woman.

 

Comparison of Vitamin B12 Sources

Below we make a quick and simple comparison between the three choices we have when it comes to vitamin B12.

Plant-Based
Vitamin B12 cannot be found in plant-based, whole-foods. However, some foods are fortified with it, including fortified nutritional yeast, vegan milks and cereals. Some forms of seaweed have vitamin B12, but in an inactive form that cannot be absorbed by our bodies and might even interfere with B12 absorption from other sources.
Supplementing B12 is imperative when following a plant-based or mostly plant-based diet.
Recommended Source!
Supplements
The recommendation is to take your B12 supplement on an empty stomach so we have the highest amount of intrinsic factor (the protein needed to absorb it) available in our stomach.
Do not take your vitamin B12 as part of a multivitamin because other nutrients mixed in the same pill can destroy active B12.
Absorption is busted by saliva when taking a chewable or sublingual pill.
Animal-based
People eating animal-based foods are still at risk of deficiency. In fact, 33% of adults are deficient, including 51% of women and 60% of pregnant women.
Supplementing vitamin B12 is particularly important for anyone over the age of 50, regardless of their diet preferences.

References