B12…. What is it and why is it important? That’s such a common question in the nutrition space. In this article, we want to clear things up and explain what this vitamin is and why it is important. First and foremost, Vitamin B12 is a water-soluble vitamin that is naturally present in some foods, and is also available as a dietary supplement. Vitamin B12 is required for the development, myelination, and function of the central nervous system, healthy red blood cell formation, and DNA synthesis just to name a few things. However, there are a TON of functions of this important vitamin!
So, now that we know what it does, how does it work? Long story short, vitamin B12 binds to the protein in the foods we eat. In the stomach, hydrochloric acid and enzymes unbind vitamin B12 into its free form. From there, vitamin B12 combines with a protein called intrinsic factor so that it can be absorbed further down in the small intestine. Experts have recently found that supplements and fortified foods that contain B12 in its free form may be more easily absorbed. The Recommended Dietary Allowance for men and women ages 14 years and older is 2.4 micrograms (mcg) daily. For pregnancy and lactation, the amount increases to around 2.6 mcg and 2.8 mcg daily.
In regards to vegans and vegetarians, it is advised to pay particular attention to this nutrient. B12 is naturally found animal products, including meat, fish, eggs, dairy, and other seafood. It is typically absent in plant foods! Vitamin B12 is synthesized only by certain bacteria and archaeon, but not by plants. The synthesized vitamin B12 is transferred and accumulates in animal tissues, which can occur in certain plant and mushroom species through microbial interaction. Very low B12 intakes can cause anemia and nervous system damage. The only reliable vegan sources of B12 are foods fortified with B12 (including some plant milks, some soy products , breakfast cereals, and nutritional yeast) and B12 supplements.
Research shows that a mix of methylcobalamin and adenosylcobalamin makes for the most bioavailable B12 for vegans. 250 mcg per day is always a great place to start.