Vitamin B12 is an essential nutrient that plays many crucial roles in the body. It is involved in red blood cell formation, cell metabolism, nerve function, and DNA synthesis (1). While many animal foods contain vitamin B12, it can be more challenging to obtain adequate amounts from plant foods alone. However, some vegetables do provide small amounts of this important vitamin. This article will explore which vegetables contain vitamin B12 and which one has the highest amount.
The Importance of Vitamin B12
Vitamin B12 is a water-soluble vitamin that is naturally present in many foods. It is required for proper red blood cell formation, neurological function, and DNA synthesis (2). Vitamin B12 also works closely with folate in many body processes. Deficiency in vitamin B12 can lead to anemia, fatigue, constipation, loss of appetite, weight loss, neurological changes, psychiatric disturbances, and more (3).
Since vitamin B12 is essential and cannot be made by the body, it must be obtained through diet or supplementation. The recommended dietary allowance (RDA) for vitamin B12 is 2.4 mcg for adults, 2.6 mcg for pregnant women, and 2.8 mcg for lactating women (4). Although deficiency is rare in younger people, the risk increases with age due to reduced absorption. It’s estimated that anywhere from 5–20% of adults over age 60 have deficiency, making it especially important for older populations to ensure adequate intake (5).
Overall, consuming sufficient vitamin B12 is vital for good health and prevention of neurological disorders. While animal foods are the highest sources, some plant foods also contain small amounts that contribute to total intake.
Animal vs. Plant Food Sources of Vitamin B12
Vitamin B12 is naturally present in many animal foods but is not found in plants. It is produced by certain bacteria and archaea, but only present in plants if they are contaminated with these organisms (6). For this reason, natural plant foods do not provide a reliable source of active vitamin B12 unless they are specifically fortified.
Here are the typical amounts of vitamin B12 provided in 3 ounces (85 grams) of some common animal foods (7):
- Beef liver: 65 mcg
- Sardines: 4.2 mcg
- Salmon: 4 mcg
- Tuna: 2.6 mcg
- Trout: 5.4 mcg
- Eggs: 1.1 mcg
- Milk: 1.2 mcg
- Chicken: 0.3 mcg
As shown above, organ meats like liver as well as fish like sardines provide very high amounts. Meat, poultry, eggs, and dairy also contain lower but significant amounts of vitamin B12.
In contrast, most plant foods provide little to no natural vitamin B12 unless they have been fortified. Here are the typical vitamin B12 amounts in 3 ounces (85 grams) of some common plant foods (8):
- Tofu: 0.7–1.5 mcg
- Tempeh: 0–1.2 mcg
- Edamame: 0 mcg
- Tahini: 0 mcg
- Spirulina: 0–1 mcg
- Nori: 0–28 mcg
- Nutritional yeast: 0–15 mcg
The levels above reflect natural vitamin B12 without fortification. As shown, most plants provide none. Seaweed like nori and supplements like nutritional yeast may contain some based on contamination, but the amount can vary widely (9, 10).
Overall, the most abundant natural sources of vitamin B12 come from animal rather than plant foods. However, with the help of food fortification and supplementation, vegetarians and vegans can also meet their needs.
Do Any Vegetables Contain Vitamin B12?
While vegetables do not naturally contain vitamin B12 unless contaminated, some may be fortified with lab-created vitamin B12 during processing.
The vegetables that most commonly contain added vitamin B12 include (11):
- Soymilk
- Meat substitutes made from soy, wheat gluten, etc.
- Breakfast cereals
- Nutritional yeast
- Lab-cultured algae like spirulina
Additionally, mushrooms exposed to UV light may have enhanced levels of vitamin B12. The UV light exposure contributes to an increase in the vitamin, though mushrooms still contain very little compared to fortified foods and supplements (12).
Overall, vegetables will not naturally provide significant levels of vitamin B12 unless purposefully fortified. Relying on contamination from soil bacteria or UV light exposure provides low, variable levels.
Which Vegetable Has the Most Vitamin B12?
The vegetable product that naturally contains the most vitamin B12 is nori seaweed. However, the amount can vary widely. Here are some approximate vitamin B12 levels per 100 grams of raw vegetable (13, 14, 15):
| Vegetable | Vitamin B12 |
|---|---|
| Nori seaweed | 28-99 mcg |
| Tempeh | 0-2.7 mcg |
| Mushrooms (UV exposed) | 0-1.9 mcg |
| Tofu | 0-1.5 mcg |
| Fermented spinach | 0-1.4 mcg |
| Kimchi | 0-1.2 mcg |
As shown, nori generally provides the highest amount of vitamin B12, ranging from 28–99 mcg per 100 grams. Other fermented foods like tempeh, kimchi, and fermented spinach contain trace amounts.
However, the vitamin B12 in these foods can vary substantially. Tempeh, for example, has been shown to provide anywhere from 0–2.7 mcg per 100 grams depending on the brand (15).
Additionally, the type of vitamin B12 found in these foods is often an inactive form known as pseudovitamin B12. This form is not bioavailable, meaning it cannot be used by your body (16).
For this reason, consuming fortified foods and supplements with active vitamin B12 is recommended over relying on vitamin B12 from vegetables to meet nutritional needs.
Top Vegetable Sources of Vitamin B12
Here are some of the top vegetable sources of vitamin B12 per 1 cup serving (17, 18, 19, 20):
| Vegetable | Vitamin B12 |
|---|---|
| Fortified soymilk | 2.9 mcg (119% DV) |
| Fortified nutritional yeast | 2.7 mcg (114% DV) |
| Fortified breakfast cereal | 2.4 mcg (98% DV) |
| Nori seaweed | 1.9 mcg (80% DV) |
As demonstrated, fortified foods like soymilk, nutritional yeast, and breakfast cereal provide a reliable source of vitamin B12. They contain a form your body can use and make it easier to meet daily needs, especially if following a vegetarian or vegan diet.
One cup (10 grams) of dried nori seaweed also contains a significant amount of vitamin B12. However, again, vitamin B12 levels found in nori are highly variable (21).
Other vegetables will at max provide only trace amounts of vitamin B12 per serving unless fortified during processing.
Meeting Vitamin B12 Needs on a Vegetarian or Vegan Diet
Those following vegetarian diets, especially vegan diets, are at greater risk of vitamin B12 deficiency compared to omnivores (22).
This is because animal foods are the primary natural source of vitamin B12. When they are excluded from the diet, this can increase the risk of inadequate intake over time if alternatives are not included (23).
The recommended intake is 2.4 mcg per day for adults, which increases during pregnancy and breastfeeding. Here are some ways that vegetarians and vegans can help meet their vitamin B12 needs (24, 25):
- Consume fortified foods like plant milks, breakfast cereals, and nutritional yeast
- Take a daily vitamin B12 supplement providing at least 10 mcg
- Consume B12-fortified meat substitutes and eggs
- Consider probiotic supplements that contain vitamin B12
- Use B12 toothpaste or mouthwash
Pairing fortified foods with a daily supplement is the most reliable method to prevent deficiency. This helps provide adequate and consistent intake of a bioavailable form of vitamin B12.
Vegans who do not supplement have been shown to have very low blood levels of vitamin B12 over time. However, vitamin B12 blood levels can be preserved when a supplement of 10 mcg per day or 2000 mcg weekly is used (26).
Therefore, a weekly supplement, fortified foods, or both should be included to meet needs on a plant-based diet due to the lack of natural vitamin B12 sources in vegetables and other plant foods.
Conclusion
In conclusion, vitamin B12 is an essential nutrient that is naturally abundant in animal foods but not found in any vegetables unless fortified or contaminated.
The vegetable containing the most vitamin B12 per serving is nori seaweed. However, vitamin B12 levels in nori and other plant foods can vary widely. Moreover, the type of vitamin B12 found in vegetables is often not usable by your body.
To meet needs, especially if following a vegetarian or vegan diet, it is important to consume fortified foods like plant milks, breakfast cereals, and nutritional yeast. Pairing these with a daily supplement is the most reliable strategy to prevent deficiency.
Including a variety of fortified foods and considering a supplement can help vegetarians and vegans obtain sufficient vitamin B12 from sources other than vegetables and animal foods. This key nutrient is critical for many aspects of health, so ensure adequate intake through proper planning and supplementation if needed.