B12 foods

This page shows the B12 in foods; general information on needs and supplements is in the vitamin B12 guide. This guide does not recommend personal doses.

Which foods contain B12?

According to NIH, B12 is found in animal foods such as fish, meat, poultry, eggs and dairy. The Turkish Hematology Association guideline also states that B12 is found in animal foods, especially red meat. Plant foods do not naturally contain B12. ^{[1] [3]}

B12 food table: micrograms per serving

The values below are taken from the NIH table, which is based on US Department of Agriculture (USDA) data. Servings are US measures (3 ounces is about 85 g, 1 cup is about 240 mL); “percent DV” is relative to the US Daily Value (2.4 µg) and is not the same as the EU adequate intake value of 4 µg. ^{[1] [2]}

Practical conclusions from the table: liver provides many times the daily need in a single serving; a serving of ground beef or a glass of milk with an egg also contributes to the reference intake; spinach, kidney beans and fruits contain no B12. The content of products sold in Türkiye may differ from those in the table; for fortified products, the label is what counts. ^[1]

How much of the B12 in food is absorbed?

The B12 in foods is bound to protein and must be released by stomach acid. According to NIH, bioavailability varies by food type: it is about three times higher in dairy than in meat, fish and poultry, and about 50% higher in supplements than in foods. When the capacity of intrinsic factor is exceeded (around 1–2 µg), absorption drops rapidly; for this reason, eating a large amount of B12 in the same meal does not mean proportionally more absorption. ^[1]

During cooking and storage, part of the B12 is degraded and loses its biological activity; in addition, the body distinguishes B12 analogs that are inactive in humans (corrinoids) and tries to absorb only the active form. For this reason, a product “containing B12” and that B12 being useful in humans are not the same thing. ^[4]

Mean B12 intake observed in adults in the EU is in the range of 4.2–8.6 µg/day; EFSA, taking these means into account, set an adequate intake (AI) of 4 µg/day. Although mean intake appears adequate, because deficiency mostly stems from absorption problems, “I eat enough meat” does not guarantee that deficiency will not occur. ^[2]

B12 in breast milk and infant nutrition

NIH reports that the mean B12 level in the milk of women whose B12 intake is above the RDA is 0.44 µg/L. For infants, the source of B12 is breast milk or formula; the mother’s B12 status therefore directly affects the infant’s status. The Turkish Hematology Association guideline states that in Türkiye the most common cause of deficiency in infancy is the mother’s B12 deficiency during pregnancy; for this reason, investigation of the mother of an infant found to be deficient is also recommended. ^{[1] [3]}

Do fortified foods provide B12?

Yes. NIH reports that fortified breakfast cereals and fortified nutritional yeast are sources of highly bioavailable B12. The B12 added during fortification is in free form; it does not need a step of release from protein binding. The amount varies greatly by brand (8.3–24 µg for nutritional yeast in the table), so the label should be read. ^[1]

Do spirulina, nori and fermented foods provide B12?

“Plant-based B12” claims are a common misconception:

• Spirulina and other blue-green algae: Most edible blue-green algae (cyanobacteria) contain a corrinoid called pseudovitamin B12, which is inactive in humans. The labels of supplements containing spirulina, Aphanizomenon and Nostoc may list high B12 values; the measured amount may not mean B12 that is active for humans. ^[4]
• Nori: The review authors consider dried purple laver (nori) the most suitable plant-based candidate available today for vegetarians; however, the same group states that the use of foods fortified with crystalline B12 should also be prepared alongside plant sources. This does not mean that nori is a sufficient and reliable source on its own. ^{[4] [5]}
• Tempeh and fermented soy: In the NIH table, half a cup of tempeh contains only 0.1 µg of B12 (3% of the Daily Value). ^[1]
• Other plant foods: Bananas, bread, strawberries, kidney beans and spinach are listed in the table at 0.0 µg. ^[1]

What can be said for vegans and vegetarians?

According to NIH, vegans and vegetarians who do not eat meat carry a higher risk of deficiency because natural B12 is limited to animal foods; fortified foods and supplements can markedly reduce this risk. ^[1]

A review of studies based on serum B12 in vegetarians (40 studies) reported the following: the deficiency rate reached 45% in infants, 17–39% in pregnant women, and a range of 0–86.5% in adults and older adults; rates were higher in vegans than in other vegetarians, and vegans not taking supplements were at particular risk. The range is so wide because the studies differed in whom and how they measured; the results should not be read as a single number for “how many people are deficient.” The review recommends that vegetarians seriously consider B12 supplementation and be screened for deficiency. ^[6]

Because deficiency can develop very early in breastfed-only infants of mothers who follow a vegan diet, reviewing B12 status with a doctor in pregnancy and breastfeeding is important. ^[1] This page does not recommend amounts or products.

Can deficiency occur even with enough from food?

Yes. Deficiency mostly stems from absorption problems (reduced stomach acid, intrinsic factor deficiency, certain medications and surgeries). In these cases, absorption of B12 taken from food can be impaired, although according to NIH, deficiency runs milder in people who can absorb free B12. The related page covers symptoms and causes. ^{[1] [3]}