What is active B12?
Active B12 is the amount of vitamin B12 that's available for your body to use.
What is its function?
Vitamin B12, together with folate and iron, plays a key role in forming red blood cells — which carry oxygen around your body.
Vitamin B12 is also important for a healthy nervous system and plays a role in protecting against heart disease.
What can cause my levels to change?
A number of things can cause vitamin B12 deficiency, these include:
- pernicious anaemia — your immune system mistakenly attacks cells in your stomach that produce intrinsic factor (which you need to absorb vitamin B12)
- diet — vegan, vegetarian, and dairy-free diets are sometimes lacking in vitamin B12
- medication — some medications, like proton pump inhibitors (PPIs), can inhibit absorption of vitamin B12
You’re also more at risk of vitamin B12 deficiency if you:
- are pregnant or breastfeeding
- are over 50 years — because you might stop producing enough hydrochloric acid in your stomach which is needed for absorption of vitamin B12
- suffer from a gastrointestinal disorder — like coeliac disease or Crohn’s disease
What are the most common symptoms?
If you don't get enough vitamin B12, it can lead to anaemia — meaning your body can't transport around enough oxygen. It can also lead to nerve damage, balance issues, and psychological issues.
Symptoms of vitamin B12 deficiency can include:
- lack of energy
- a sore red tongue
- mouth ulcers
- pins and needles
- muscle weakness
- disturbed vision
- mood changes
- feeling depressed
- memory problems
What can I do to change them?
You can increase your vitamin B12 levels by eating foods high in vitamin B12 like:
- organ meats — like liver and kidney are the richest sources of vitamin B12
- fish — like clams, sardines, salmon, and tuna
- milk and dairy products
Vitamin B12 is only naturally available in meat, fish, and dairy. But there are fortified plant-based sources of vitamin B12 like:
- fortified milk alternatives
- fortified cereals
- fortified nutritional yeast
If you're not getting enough vitamin B12 from your diet, you might need a supplement. It’s usually available as cyanocobalamin — a form which your body can easily convert and use. It’s also possible to get a vitamin B12 injection — this is especially useful if your deficiency is caused by absorption issues in your stomach. The form hydroxocobalamin can be given every three months.