From the Guidelines
The best source of vitamin B12 is animal products, particularly organ meats like liver, as well as clams, beef, fish, eggs, and dairy products. For those following plant-based diets, B12-fortified foods (nutritional yeast, plant milks, breakfast cereals) and supplements are essential since B12 is not naturally found in plant foods 1. If supplementing, cyanocobalamin is typically recommended at 2.4 mcg daily for adults (higher doses for those with deficiency, typically 1000-2000 mcg daily). Sublingual tablets, oral supplements, or B12 injections (prescribed for severe deficiency) are all effective delivery methods. B12 is crucial for nerve function, DNA synthesis, and red blood cell formation. The body can store B12 for years, but regular consumption is important, especially for vegans, older adults, those with absorption issues (like pernicious anemia or after gastric surgery), and people taking certain medications like metformin or proton pump inhibitors.
Some key points to consider when evaluating the best source of vitamin B12 include:
- Diet low in vitamin B12 (without regular use of over-the-counter preparations), for example, in people who follow a diet that excludes, or is low in, animal source foods (such as a vegan diet or diets that exclude meat for religious beliefs) 1
- Health conditions such as atrophic gastritis affecting the gastric body, coeliac disease or another autoimmune condition (such as thyroid disease, Sjögren syndrome, or type 1 diabetes) 1
- Medicines such as colchicine, H2 receptor antagonists, metformin, phenobarbital, pregabalin, and primidone 1
It's also important to note that vitamin B12 is stored in relatively large quantities in the liver, and sources include all animal produce, to a lesser extent eggs and dairy produce, and fortified foods 1.
In terms of specific food sources, some of the best sources of vitamin B12 include:
- Animal foods only: meat, fish, poultry, cheese, milk, eggs, vitamin B12-fortified soy milk 1
- Organ meats like liver 1
- Clams, beef, fish, eggs, and dairy products 1
From the FDA Drug Label
Vitamin B12 is not present in foods of plant origin, but is abundant in foods of animal origin The average diet supplies about 5 to 15 mcg/day of Vitamin B12 in a protein-bound form that is available for absorption after normal digestion. The best source of B12 is foods of animal origin.
- Examples include:
- Meat
- Fish
- Poultry
- Eggs
- Milk products 2
From the Research
Sources of Vitamin B12
- Animal foods are the primary sources of vitamin B12, including meat, milk, egg, fish, and shellfish 3
- The bioavailability of vitamin B12 from these sources varies, with fish meat, sheep meat, and chicken meat having an average bioavailability of 42%, 56%-89%, and 61%-66%, respectively 3
- Eggs have a lower bioavailability of vitamin B12, at less than 9% 3
- Some plant foods, such as dried green and purple lavers (nori), contain substantial amounts of vitamin B12, but other edible algae may not be suitable as a source of vitamin B12 3
- Fortified breakfast cereals are a valuable source of vitamin B12, particularly for vegans and elderly people 3
Alternative Sources of Vitamin B12
- Vitamin B12 can also be obtained through supplements, including methylcobalamin, adenosylcobalamin, and hydroxocobalamin 4, 5
- These supplements can be administered orally or intramuscularly, with sublingual administration being a potentially effective and convenient option 6
- The bioavailability of these supplements may be influenced by factors such as gastrointestinal health, age, and genetics 5
Importance of Vitamin B12
- Vitamin B12 is essential for various bodily functions, including hematopoiesis, nerve function, and DNA synthesis 7
- A deficiency in vitamin B12 can have serious health consequences, particularly for pregnant women, infants, and elderly people 7
- The recommended adequate intake of vitamin B12 is 4.0 μg/d for adults, with higher requirements during pregnancy and lactation 7