We need to get serious for a moment. While vegetarians and vegans get other vitamins in adequate amounts, taking a vitamin B12 supplement is a must for vegans, since they don’t get any through their diet. And while vegetarians do get some B12 through either dairy or eggs, it may not be enough, especially if their intake is modest or only occasional.

Vitamin B12, like the other B vitamins, is important for metabolism. It helps in the formation of red blood cells, and in the maintenance of the central nervous system, among other important things. The good news is that the body can store it for years, protecting you if you miss taking some now and again. However, if your body runs out of its supplies, because it’s been missing from your diet for a long time or has only been taken occasionally, there’ll be very serious consequences.  Deficiency causes a type of anemia called megaloblastic anemia, damage to the spinal cord, brain and peripheral nerves, especially in the arms and legs. The nerve and brain damage can be permanent, and can cause dementia and psychiatric disorders. Low or marginal vitamin B12 status in pregnant women increases the risk for neural tube birth defects.

Some people wonder why, if people have the anatomy and physiology of herbivores, we need to take vitamin B12 supplements. Can’t we get all the B12 we need from plant foods? Vitamin B12 is produced by bacteria that naturally live in the soil. In ancient times, plant foods were pulled from the ground or stored on it or even under it. There was little peeling and washing of the produce, and very little hand-washing too, and so they naturally ingested enough B12 from the soil on the produce directly. Today, we can get B12 from animal products because the animals ingest soil along with the plants they eat. When we eat meat, we get the B12 along with it, but of course we’re only getting it second hand.  B12 can be formed by some of the bacteria in our intestines, but it’s too far down at that point to be absorbed and put to use. Some people thought that seaweed or fermented foods such as tempeh could provide us with B12, but unfortunately this hasn’t panned out. While some foods are fortified with B12, they may not be consumed regularly or in sufficient quantities to meet the need.  So the choice comes down to eating dirt or taking supplements. You can guess which we’d recommend!

The amount in a high-quality one-a-day type vitamin is usually at least 6mcg, which will be fine for many people, although taking extra is considered safe. However, pregnant women and folks over 50 need more. To be on the safe side many health authorities recommend anywhere from 100mcg –500mcg daily. People taking certain medications, to control stomach acid or diabetes for example, may need even more. A percentage of people who lack enough stomach acid, or who don’t produce a secretion necessary for B12 absorption, need much more. Both groups need to ask their doctor to find the right amount for their individual circumstances.

We wrote an article for physicians with much more detail on this topic, which has recently been published in a medical journal. The bottom line is that taking B12 regularly is a must for vegans and strongly recommended vegetarians.