Vitamin B12 for Vegans
Vitamin B12 is an essential vitamin for everyone, but vegans especially.
I talk about vitamin B12 in my Nutrition Handbook – Healthy Vegan Families. It is such an important nutrient for vegans that I decided to share the information from Healthy Vegan Families with you for free.
What Is Vitamin B12?
Vitamin B12 is an essential vitamin, and not available naturally in a useful form or amount in any plant based foods. B12 is used by the body to build DNA and RNA, which are the genetic code for your body, and are necessary to build all of your cells. B12 is also necessary to maintain the protective sheaths around your nerves to keep them safe.
Absorption of vitamin B12 in your body depends on something called intrinsic factor, which is released in the stomach during digestion to break down B12. Vitamin B12 deficiency can be caused by either a lack of B12 in the diet (more likely in vegans) or a lack of intrinsic factor, which can happen as people age, no matter their diet. It is recommended that people start to supplement B12 after they turn 50.
Signs of B12 Deficiency
Lack of B12 can cause fatigue, a sore tongue, loss of appetite, constipation, and nerve pain. Long term B12 deficiency can cause nerve damage and paralysis which is permanent and non-reversible. So it is imperative that you supplement with B12.
B12 deficiency can also cause a type of anemia, which can be confused with a folate deficiency. So it is very important that you speak to a trained medical professional about any B12 or folate deficiency concerns.
How to Get B12
Vegans must supplement B12, or get it from fortified foods. B12 is actually from a bacteria in the dirt, so animals ingest it while they’re eating grass, and that is how it ends up in animal products.
These days, many vegan foods are fortified with B12 because it is such an important nutrient. While you can get B12 from fortified foods, there is no way to guarantee the quality of the B12 in them. You would also need 3 serves of fortified foods a day to make sure you get enough B12.
You cannot overdose on B12, as your body will just flush out any excess in your wee. Given the permanent and horrific damage that vitamin B12 deficiency can cause, my recommendation is that you supplement B12 in addition to eating fortified foods. That way you guarantee that you are getting enough.
The table below shows you how much Cyanocobalamin B12 to supplement. Cyanocobalamin is the best form to supplement.
| Age | μg/day |
| 6 – 12 months | 0.5 |
| 1- 3 years | 0.9 |
| 4 – 8 years | 1.2 |
| 9 – 13 years | 1.8 |
| 14 – 18 years | 2.4 |
| Adults | 2.4 |
| Pregnancy | 2.6 |
| Breastfeeding | 2.8 |
When Do You Need to Start B12 Supplements?
Breastfed babies will get enough vitamin B12 in their milk, and formula is supplemented with B12, so you don’t need to worry about supplementing B12 until your baby is weaning. When you baby starts to drop off the amount of breast milk or formula that they’re drinking, you can start supplementing with B12 drops.
The body stores and recycles B12, so when you first go vegan, if you have previously eaten meat, dairy products or eggs, then it will probably take a couple of years for you to start to become deficient. Children, however, will have had less time to build up a store, so can go deficient faster.
What About Plant Sources of B12?
There are some plant based foods that contain B12. Miso and algae (including spirulina) contain an inactive form of B12 that the body cannot absorb. This inactive form also blocks absorption of active B12, so you need to be careful with high levels of foods like miso and algae.
Other plant foods like mushrooms and nori have a small amount of B12 in them, but not enough to meet daily requirements.
