Why Does Our Body Need Vitamin B12?

Vitamin B12, also known as cobalamin, is an indispensable water-soluble micronutrient of bacterial origin. As humans are incapable of synthesizing this vitamin on their own, we acquire it through dietary means. Notwithstanding its water solubility, the body can retain it for several years, mainly in the liver. Nevertheless, vegans should monitor their vitamin B12 levels regularly, as they are prone to a deficiency.

Vitamin B12 Functions

The body needs vitamin B12 for several important functions. Some of the key roles of vitamin B12 in the body include:

• Production of Red Blood Cells: Vitamin B12 is essential for the production of healthy red blood cells. A deficiency of vitamin B12 can lead to a type of anemia called megaloblastic anemia. This condition is characterised by the bone marrow producing immature, large red blood cells (megaloblasts) that don’t function properly.
• Maintenance of the Nervous System: Vitamin B12 plays a crucial role in maintaining the health of the nervous system. It helps in the production of myelin, a fatty substance that forms a protective covering around nerve fibers. Myelin helps in the transmission of nerve signals, and its breakdown can lead to nerve damage.
• Metabolism: Vitamin B12 is important for the metabolism of various nutrients, including carbohydrates, proteins, and fats. It helps convert food into energy that the body can use.
• Brain Function: Vitamin B12 is important for cognitive function and mood regulation. Studies have shown that low levels of vitamin B12 are associated with a higher risk of depression and cognitive decline in older adults. [1] The blog post on how nutrition influences our brain provides information about the link between nutrition, and our mood and decision-making processes.
• DNA Synthesis: Vitamin B12 plays a vital role in the synthesis of our genetic material, our DNA. It is necessary for the proper functioning of the enzyme called methionine synthase, which converts the amino acid homocysteine into methionine. Methionine is a building block for DNA and essential for the proper replication of genetic material in the body.

Vegan and Non-Vegan Vitamin B12 Sources

Non-vegan natural sources of vitamin B12 include meat and dietary products. Especially liver and kidneys, clams, sardines, salmon and tuna. But no worries if you are vegan, there are supplements and vegan foods than contain vitamin B12.

And on a side note, people who eat animal products for their vitamin B12 source should know that they propably indirectly consume supplements. Animals raised in factory farms are often fed a diet that is deficient in this vitamin, as their diets consist primarily of corn, soy, and other grains, which are not natural sources of vitamin B12. Therefore, factory-farmed animals are typically given supplements to promote their growth and prevent vitamin B12 deficiency.

Some plant-based foods like dried green and purple lavers (nori) contain significant amounts of vitamin B12. However, other edible algae have little to none. Edible blue-green algae (cyanobacteria) used for human supplements mainly contain pseudovitamin B12, which is inactive in humans and unsuitable as a vitamin B12 source. [2]

The sources of vitamin B12 are primarily animal-based foods, but there are a few plant-based sources that provide vitamin B12. These include:

• Nutritional yeast
• Marmite
• Nori
• Shiitake mushrooms
• Fortified milk alternatives

Nutritional Yeast

Nutritional yeast is made from a type of yeast known as Saccharomyces cerevisiae, which is grown on molasses or other similar substrates. There are two types of nutritional yeast available in the market, fortified and unfortified. Unfortified nutritional yeast contains naturally occurring B vitamins, including B1 (thiamine), B2 (riboflavin), B3 (niacin), B6 (pyridoxine), and folate, which are produced by the yeast cells during fermentation. However, unfortified nutritional yeast does not contain vitamin B12 as yeast cannot produce this vitamin. In contrast, fortified nutritional yeast has synthetic B vitamins added to it, including vitamin B12 in the form of cyanocobalamin. [3] Cyanocobalamin is a stable and inexpensive form of vitamin B12 that is commonly used in food fortification. The amount of vitamin B12 added to fortified nutritional yeast can vary, but it is typically around 2-4 micrograms per tablespoon. The recommended daily intake of vitamin B12 for adults is at least 2.4 micrograms per day.

Marmite

Marmite is made from yeast extract, and a single 4-gram serving of Marmite can provide up to 50% of the recommended daily intake of Vitamin B12 for an adult. This makes it a popular food choice for vegans and vegetarians, who may not get enough Vitamin B12 in their diet from other sources.

Nori

Nori is a popular edible seaweed that is used in Japanese cuisine and is a common ingredient in sushi. It is typically made by shredding and pressing fresh seaweed into thin sheets that are then dried and roasted. One of the nutritional benefits of nori is that it contains small amounts of vitamin B12. While most seaweeds do not contain vitamin B12, nori is an exception.

Shiitake Mushrooms

Shiitake mushrooms are a flavorful and nutritious ingredient that is commonly used in Asian cuisine. They are a type of edible mushroom that grows on the logs of deciduous trees and are widely cultivated in many parts of the world. While shiitake mushrooms are not a significant source of vitamin B12, they can provide a small amount of this important nutrient.

Fortified Milk Alternatives

Fortified milk alternatives are a popular choice for obtaining Vitamin B12. It’s important to check the label to ensure that it contains adequate amounts of this nutrient. The amount of Vitamin B12 can vary depending on the brand and the specific product, so it’s important to choose a variety that provides at least 2.4 micrograms of Vitamin B12 per serving, which is the recommended daily intake for adults.

Tempeh

Tempeh is a fermented soybean product that is a good source of protein, dietary fiber, and several vitamins and minerals. However, despite what many people believe tempeh is not a reliable source of Vitamin B12. While tempeh is often marketed as a meat substitute and a source of nutrients for vegetarians and vegans, it is important to note that Vitamin B12 is not naturally present in tempeh. Some brands of tempeh may be fortified with Vitamin B12, but this is not always the case.

Keep in mind that the vitamin B12 content in these plant-based sources is relatively low and may not be enough to meet the daily recommended intake. For this reason, it’s recommended that vegans and vegetarians who don’t consume animal products take a vitamin B12 supplement or consume foods fortified with vitamin B12 to ensure they are meeting their daily requirements.

What’s Important to Know About Vitamin B12 Supplements

Adequate intake of vitamin B12 can provide numerous benefits, including improved cognitive function, reduced risk of anemia, and improved mood. In some cases, vitamin B12 supplements may also help alleviate symptoms of depression and improve energy levels. However, there are some important things to know about vitamin B12 supplements.

Recommended Daily Intake

The recommended daily intake of vitamin B12 varies based on age, sex, and other factors, but generally ranges from 2.4 to 2.8 micrograms per day for adults. However, some people may require higher doses, such as those with a deficiency or absorption issues. It’s important to talk to a healthcare provider before taking vitamin B12 supplements.

Types of Supplements

Liquid drops are convenient for absorption, but may be more expensive. They are easy to use and quickly absorbed into the bloodstream through the lining of the mouth. Tablets and capsules are widely available and affordable. However, they may take longer to absorb and contain fillers or other inactive ingredients that can be allergenic or irritating to certain individuals.

Absorption

The body’s ability to absorb vitamin B12 decreases with age, and some people may have difficulty absorbing enough vitamin B12 from their diet due to certain conditions, such as pernicious anemia or gastrointestinal issues. In such cases, supplements can help provide the necessary vitamin B12.

Different Forms of Vitamin B12

Different forms of Vitamin B12 have unique benefits and limitations, making it important to consider which form a supplement contains. The four main types used in supplements are cyanocobalamin, hydroxocobalamin, methylcobalamin, and adenosylcobalamin. Cyanocobalamin is the most commonly used due to its stability and affordability. Other forms may be more easily absorbed and utilized by the body, particularly methylcobalamin and adenosylcobalamin. It effectively treats cyanide poisoning by binding to cyanide to form a non-toxic compound that the body can eliminate. Moreover, people with kidney disease may benefit from hydroxocobalamin because the body eliminates it at a slower rate than other forms of vitamin B12, making it potentially more effective in treating vitamin B12 deficiency in these individuals.

Risks of Overdose

Vitamin B12 is a water-soluble vitamin, which means that excess amounts are typically excreted in the urine. However, taking high doses of vitamin B12 supplements can potentially cause side effects, such as acne, diarrhea, and skin rash. It’s important to stick to the recommended daily intake or the dosage recommended by a healthcare provider.

Interactions with other Medications

Vitamin B12 supplements can interact with certain medications, such as proton pump inhibitors and metformin, which can affect the body’s absorption of vitamin B12. It’s important to talk to a healthcare provider before taking vitamin B12 supplements if you are taking any medications.

[1] Y. Soh, D. H. Lee, and C. W. Won, “Association between Vitamin B12 levels and cognitive function in the elderly Korean population,” Medicine, vol. 99, no. 30, p. e21371, Jul. 2020, doi: 10.1097/MD.0000000000021371.

[2] F. Watanabe, “Vitamin B12 Sources and Bioavailability,” http://dx.doi.org/10.3181/0703-MR-67, vol. 232, no. 10, pp. 1266–1274, Nov. 2016, doi: 10.3181/0703-MR-67.

[3] “Vegan Sources of B12 | Amino Mantra | Amino Mantra.” https://aminomantra.co.nz/blogs/news/vegan-sources-of-b12 (accessed Feb. 22, 2023).