Don’t Forget Your Vitamin B12
A vegan diet rich in fruits, vegetables, whole grains, and legumes provides plenty of protein and an abundance of vitamins and minerals to meet nutritional needs. You’ll find plenty of calcium in green leafy vegetables and legumes. However, there is one nutrient that merits a bit of simple planning.
Vitamin B12, which is essential for healthy nerves and healthy blood, is not produced by animals or plants. It is formed by bacteria and other one-celled organisms. Animal products commonly contain B12 formed by bacteria in animals’ intestinal tracts. While B12 is also formed in the human intestine, it occurs after the point where the vitamin can be readily absorbed.
Vitamin B12 needs can be met by consuming a variety of supplemented foods, including fortified breakfast cereals, fortified soymilk, fortified meat analogues, and some brands of nutritional yeast. However, the most convenient and reliable source is a daily multivitamin. All common brands for children and adults contain more than enough B12. Spirulina, miso, and seaweed are not reliable sources of vitamin B12.
We recommend that all adults and children take a daily multivitamin or a B12 supplement of at least 5 micrograms per day. The recommended dietary allowance for adults is 2.4 micrograms per day, with increased requirements for women who are pregnant or breastfeeding.
Most cases of B12 deficiency have nothing to do with diet. Rather, individuals who lose their ability to absorb the vitamin become deficient no matter what sort of diet they follow and need treatment with injectable or high-dose oral B12.
In the nonindustrialized world, where bacterial contamination commonly brought traces of B12 to foods, B12 deficiency is largely prevented. However, modern hygiene has eliminated this source, just as indoor living has largely eliminated sunlight, nature’s source of vitamin D. A daily multivitamin restores these essential nutrients.