Vitamin B12 (cobalamin) is required by the body to synthesize genetic materials (DNA) and for energy production in the cells. Low or deficient in this essential nutrient can manifest in many ways. One may have a sore and red tongue, mouth ulcers, feeling pins and needles all over the body, irritable, and suffer from depression [1]. These symptoms are non-specific, many who are low in vitamin B12 are not aware of it.

One of the most common reasons for low vitamin B12 is insufficient absorption from the diet. The top vitamin B12 sources are animal-based foods, especially in liver, meat, ham, fish, and seafood. As such, vegetarians and vegans who eat only plant-based foods are considered at risk of vitamin B12 deficiency. The recommended daily allowance for vitamin B12 is 2.4 µg for adults [2].

A research review found B12 deficiency is common among vegetarians: 62% of pregnant women, up to 86% of children, up to 41% of teenagers, and almost 90% of elderly [3]. Hence, one needs to ensure sufficient intake of vitamin B12, especially if adopting a plant-based diet. Contrary to popular beliefs that vitamin B12 can also be obtained from animal foods, there are some vitamin B12-containing plant food sources as well [4].

Fortified breakfast cereals

Today, many breakfast cereals have vitamins and minerals added during the manufacturing process to increase the products’ nutritional values. Vitamin B12 is one of the commonly added nutrients. In fact, the addition of micronutrients in breakfast cereals, call fortification, is a significant public health strategy to improve the population’s nutritional levels [5].

Fermented foods

Vitamin B12 is not produced by animals or fishes directly. Instead, they are by-products of bacteria fermentation [6]. For this reason, many fermented plant foods such as fermented beans and vegetables also contain vitamin B12. For example, tempeh, a ferment soy product, has a fair amount of vitamin B12 (1.9 µg /100g) [7]. Similarly, vitamin B12 was also found in traditional Korean fermented foods such as kimchi (17.12 μg / 100 g) and Korean bean paste (1.85 μg/100g) [8]. Sauerkraut, a fermented vegetable, can also contain up to 7.2 μg/100 g of vitamin B12 by adding a type of bacteria, Proprionibacteria sp., to cabbage [9].

Mushrooms

Edible mushrooms can be sources of vitamin B12 as well. Black trumpet (Craterellus cornucopioides) and golden chanterelle (Cantharellus cibarius) mushrooms contained considerable levels (1.09-2.65 µg/100 g dry weight) of vitamin B12 according to a Japanese study [10]. Additionally, the B12 contents of commercially available dried shiitake mushroom were tested to have an average B12 value of approximately 5.6 μg / 100g dry weight [10]. Even the commercially farm white button mushrooms contained vitamin B12 in their outer peels, suggesting bacteria synthesis of cobalamin on the surface [11].

Seaweeds and algae

Many types of seaweeds also contain vitamin B12. Nori, or purple laver, contains between 12-68.8 μg / 100g of vitamin B12. Dulce, 10 – 12 μg / 100g [12]. Most impressively, the vitamin B12 content of Spirulina, the blue-green algae, can be as high as 329 μg / 100g [12]. Feeding dried nori to vitamin B12-deficient rats improved the rats’ vitamin B12 status [13].

Organic produces

Vegetables can also be enriched with vitamin B12 using organic fertilizers. Vitamin B12 content of spinach leaves increased to approximately 0.14 μg/100 g fresh weight with cow manure as fertilizer [14]. In fact, enhancing soil content with B12-enriched fertilizers is a promising way to increase the B12 content of fruits and vegetables [15].

Conclusion

Vegans and vegetables must be conscious of their vitamin B12 levels since this essential nutrient is not widely available in most plant-based foods. If you are on a plant-based diet, make sure to include fortified breakfast cereals, fermented foods, mushrooms, seaweeds and algae in your diet. Also, eat organic if you can. All these foods can help to boost your vitamin B12 intake.