We include products we think are useful for our readers. If you buy through links on this page, we may earn a small commission. Here’s our process.
Vitamin B12 is an essential nutrient for good health. Most people can obtain it from a varied diet that includes animal products. However, people eating a plant-based diet can only get vitamin B12 from fortified foods or supplements.
People who may be at risk of vitamin B12 deficiency include older adults, people following a vegan diet, and individuals with increased vitamin B12 requirements due to specific health conditions.
Animal products, such as meat, fish, and eggs, contain vitamin B12 in varying amounts. The following is a list of good sources:
- canned tuna
- low fat yogurt
- low fat milk
- chicken breast
A person should consume these foods in moderation as part of a healthful diet. Learn how to eat a healthful diet here.
The above food sources are all unsuitable for people following an entirely plant-based diet.
Vitamin B12 is not present in plant foods, so people on a plant-based diet need to obtain it through fortified foods and supplements.
Foods that are sometimes fortified and may contain vitamin B12 in varying amounts include:
- plant milk, such as soy, almond, oat, cashew, and coconut milk
- breakfast cereals
- margarine and spreads
- nutritional yeast
- fruit juice
- dairy-free yogurt
It is important to read the nutritional information on a fortified product to ensure that it contains vitamin B12.
Some foods and drinks can interfere with vitamin B12 intake:
Folic acid-fortified foods
Folate (vitamin B9) is an essential nutrient, especially before and during pregnancy. The Centers for Disease Control and Prevention (CDC) state that women of reproductive age need 400 micrograms (mcg) of folic acid (synthetic folate) each day.
However, too much folic acid can mask a vitamin B12 deficiency. Research suggests that high folate levels can even exacerbate the anemia and cognitive symptoms associated with a lack of vitamin B12. For these reasons, folic acid intake from fortified foods should not exceed 1,000 mcg daily in adults with a good overall health status.
Research has suggested that the consumption of alcohol may reduce vitamin B12 levels.
An older study indicated that moderate alcohol intake diminished vitamin B12 by 5% among “healthy, well-nourished, postmenopausal women.”
Foods with insufficient vitamin B12
Some people believe that certain plant-based foods are good sources of vitamin B12. These foods include:
However, many researchers believe that these foods are not adequate to correct a deficiency of vitamin B12. For instance, the vitamin B12 in cyanobacteria, such as spirulina, has very low bioavailability.
Therefore, although people can include the above foods as part of a healthful diet, they should not rely on them as a source of vitamin B12.
The recommended daily allowance (RDA) for vitamin B12 varies according to a person’s age and whether they are pregnant or breastfeeding.
The following table shows the RDA for vitamin B12:
|14 years and over||2.4 mcg|
|9–13 years||1.8 mcg|
|4–8 years||1.2 mcg|
|1–3 years||0.9 mcg|
|7–12 months||0.5 mcg|
|0–6 months||0.4 mcg|
|During pregnancy||2.6 mcg|
|While breastfeeding||2.8 mcg|
There is no known risk of having too much vitamin B12.
Vitamin B12 supplements are available in the form of tablets or liquids that a person can take under the tongue (sublingually).
People eating a plant-based diet may need additional vitamin B12 in the form of supplements, especially when pregnant or breastfeeding.
Additionally, older adults, people with gastrointestinal conditions, and those on certain medications, including proton pump inhibitors and metformin, may need to take a supplement.
The absorption of vitamin B12 can vary from about 56% of a dose of 1 mcg to 0.5% of a dose of 1,000 mcg. Therefore, if someone consumes vitamin B12 less frequently, they will need a higher total amount to achieve a sufficient absorbed quantity.
Researchers have suggested that people supplement vitamin B12 with either 50–100 mcg daily or 2,000 mcg weekly. People should chew the tablets or allow them to dissolve in the mouth to maximize the absorption.
If a person has a severe vitamin B12 deficiency, a doctor may advise them to have injections to increase their levels of this nutrient.
Vitamin B12 is an essential nutrient, and deficiency can lead to severe complications and ill health.
People who eat a varied diet and are generally in good health can obtain the required amount from food. However, older adults, those on certain medications or with gastrointestinal issues, and people who follow a plant-based diet may be more at risk of deficiency. These people can take a supplement or speak to their doctor, who may recommend vitamin B12 injections.
Those on a vegan or mostly plant-based diet should be wary of information sources advising that foods such as seaweeds deliver adequate amounts of vitamin B12. Research suggests that this is incorrect and that those on a plant-based diet should include fortified foods and supplements.
A person should speak to their doctor if they have any concerns about nutritional supplements.