foods high in vitamin b12 vegan

Evidence Based

Medically reviewed by Sara Osman,RD,PT

Introduction

Vitamin B12 is a water-soluble vitamin that contains the mineral cobalt and is therefore also referred to as cobalamin.

Vitamin B12 is readily available in foods of animal origin but not available in plant-based foods. However, fortified breakfast cereals and fortified nutritional yeasts are good sources of vitamin B12 that have high bioavailability. [1]

Also, vitamin B12 has the largest and most complex chemical structure of all the vitamins.

  • Vitamin B12 is processed in the stomach and the small intestine before being released into circulation and the liver takes up almost 50% of circulating nutrient. The remainder is transported to other tissues. [4,6]
  • Vitamin B12 bioavailability varies with foods and is 3 times higher in dairy products than in meat, fish and poultry. [1]
  • Similarly, the bioavailability of vitamin B12 from dietary supplements is about 50% higher than that from food sources. [1]
  • However, absorption rates decrease with 1–2 mcg vitamin B12 and doses higher than that. [1,6]
  • Although vitamin B12 is a water-soluble vitamin, the body stores an amount of the nutrient in the liver, around 1 to 5 mg which could possibly last 3-5 years. [1,5]
  • Significant amounts of cobalamin are also found in the kidneys. [7]
  • In case of inadequate intake, the body uses the stored nutrient levels and it might take afew years for deficiency symptoms to appear. [1]
  • The excretion of vitamin B12 is proportional to body stores. [4]
  • Various studies have indicated losses of 0.1 to 0.2 per cent of the B12 pool per day. [6,7]
  • It is usually excreted through stools but also in the urine and through the skin. [3,4]

Body Functions

Central nervous system functions [1]

Healthy red blood cell formation [1,3]

DNA synthesis [1,3]

Critical for folate metabolism [2]

Reduces breast cancer risk [2]

Brain and nerve cells development [3]

Protects cells from oxidative DNA damage [8]

Reduces inflammation [8]

Central nervous system functions [1]

Healthy red blood cell formation [1,3]

DNA synthesis [1,3]

Critical for folate metabolism [2]

Reduces breast cancer risk [2]

Brain and nerve cells development [3]

Protects cells from oxidative DNA damage [8]

Reduces inflammation [8]

Recommended Daily Intake

how much vitamin b12 cobalamin is recommended daily
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Deficiency Symptoms

Megaloblastic anemia [1,2,3]

Stomach inflammation [2]

Fatigue,weakness [3]

Depression [2,3]

Palpitations [1]

Pale skin [1]

Dementia [1,2]

Numbness and tingling in the hands and feet [1,2,3]

Infertility [1]

Glossitis of the tongue [1,2]

Low counts of white and red blood cells [1]

Megaloblastic anemia [1,2,3]

Stomach inflammation [2]

Fatigue & weakness [3]

Memory loss, confusion [3,4]

Depression [2,3]

Heart palpitations [1]

Pale skin [1]

Dementia [1,2]

Appetite and weight loss [1,2]

Infertility [1]

Difficulty walking; memory loss [2]

Numbness & tingling in the hands & feet [1,2,3]

Glossitis of the tongue [1,2]

Low counts of white and red blood cells [1]

Vitamin B12 Food Sources

foods high in b12 vegan
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Excessive Intake/ Toxicity Side Effects

Toxicity is rare for this nutrient as it’s a water-soluble vitamin and the body removes excess amount instantly. [1,2,4]

Groups At Risk of B12 Deficiency

Vegans or vegetarians

Vegans or vegetarians who consume no or only some animal products(e.g. dairy products) are at risk of developing vitamin B12 deficiency. It is highly recommended for such individuals to consume vitamin B12 fortified foods or supplements regularly. [1,3]

Gastrointestinal disorders in individuals

Individuals with stomach and small intestine disorders, such as celiac disease and Crohn’s disease, may be unable to absorb vitamin B12 efficiently from food to maintain healthy body levels. [1]

Infants of vegan women

Exclusively breastfed infants of vegan or vegetarian women might have lower vitamin B12 levels and might develop vitamin B12 deficiency at an early age. Untreated vitamin B12 deficiency in infants can result in neurological damage, failure to thrive, developmental delays, and anaemia. [1,3]

Older adults

Absorption of vitamin B12 from food is impaired in older adults above 60 years old placing them at risk for vitamin B12 deficiency. [2,3] Lack of stomach acid needed to liberate vitamin B12 from food is known to be one of the reasons for vitamin B12 deficiency in these demographics. [3]

B12 Interaction With Other Nutrients

  • Folate – Vitamin B12 plays a critical role in folate metabolism. [2,4,7]
References

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Medically reviewed by Sara Osman,RD,PT

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