A vitamin B12 deficiency means your body has too little B12 for your nerves and blood production. The complaints, such as fatigue, tingling and concentration problems, often build over months. Two blood values usually give the most insight here: B12 itself and folate.
I notice that a B12 deficiency is often recognised late, precisely because the complaints come on so gradually. You get used to the tiredness, and you put the tingling down to a bad posture.
Below you walk through the signs and the tests calmly.
What does vitamin B12 do in your body?
Vitamin B12 is needed to make red blood cells and for a healthy nervous system. If you get too little or absorb it poorly, both systems can get into trouble. That explains why a deficiency can cause both tiredness and tingling.
You get B12 mainly from animal products, such as meat, fish, eggs and dairy. That is why people on a plant-based diet are more at risk. Absorption can also falter, for example at an older age or with certain stomach problems.
Which symptoms fit a B12 deficiency?
The complaints of a B12 deficiency range from tiredness to tingling and mood complaints. Because they come on gradually and resemble other causes, a deficiency often goes unnoticed for a long time. A pattern of several complaints together says more than a single symptom.
Signs that often fit a B12 deficiency:
- Persistent fatigue and a feeling of being drained
- Tingling or a numb feeling in hands or feet
- Concentration and memory problems
- Pale or slightly yellowish skin
- A smooth, sensitive tongue or mouth complaints
- Low mood or irritability
Many of these complaints also fit other causes, such as anaemia or a slow thyroid. That is why a single symptom says little. If you want to look more broadly at the cause of your tiredness, read our pillar always tired: which blood values to test for fatigue.
Who is more at risk of a deficiency?
Some groups are more likely to have a B12 deficiency, especially if intake or absorption falls short. In women, a plant-based diet often plays a role, because B12 is found mainly in animal products.
Absorption can also play a part. At a later age, with certain stomach problems or with long-term use of acid reducers, your body sometimes absorbs B12 less well.
You see an increased risk in, among others:
- Vegetarians and vegans
- Women who are pregnant or breastfeeding
- People who use acid reducers or metformin long-term
- Older adults, due to reduced absorption
Which blood values give insight?
You bring a B12 deficiency into view with two values that complement each other. Vitamin B12 shows how much is available, and folate often sits alongside it because a shortage of either gives similar complaints. The table below sums it up.
| Value | What it measures | What it shows |
|---|---|---|
| Vitamin B12 | The amount of B12 in your blood | A low value can point to a deficiency |
| Folate | The folate reserve in your blood | A shortage gives similar complaints and anaemia |
The values are linked, and that is exactly why you preferably look at them in combination. A borderline case can sometimes call for further testing, for example an active B12 measurement. What is useful depends on your complaints and your diet.
Want to test specifically? The B vitamins panel measures B12 and folate among others in one draw. So you see the picture in context rather than one isolated number.
When should you have your B12 checked?
One tired week says little. It gets more interesting if the complaints last longer or if several signals come together, especially tingling. Then it makes sense to have your values checked.
Consider a check if you recognise this:
- You have been tired for weeks without a clear reason
- You have tingling or a numb feeling in hands or feet
- You eat few or no animal products
- You notice memory or concentration problems
If you mainly have complaints in the winter months or get little sun, also look at your vitamin D. Read about that in vitamin D deficiency in women: symptoms and when to test. You always discuss an abnormal result with your GP.
Frequently asked questions
How quickly does a B12 deficiency recover?
That differs per person and per cause. With supplementation, some women notice more energy after a few weeks, but nerve complaints can need longer to improve. Your doctor decides which form and amount fit.
Can I have a B12 deficiency while I eat meat?
Yes, you can. Besides too little intake, absorption can also falter, for example with stomach problems or certain medication. That is why a doctor looks not only at your diet but also at possible absorption problems.
Does a B12 deficiency always cause anaemia?
No, not always. A deficiency can cause complaints before your haemoglobin has dropped, especially nerve complaints can appear early. That is why testing is useful, even if your blood count still looks normal.
References
- Health Council of the Netherlands (Gezondheidsraad). Towards an adequate intake of vitamin B12. The Hague: Gezondheidsraad, 2024.
- Netherlands Nutrition Centre (Voedingscentrum). Vitamin B12. Available via voedingscentrum.nl.
- Dutch College of General Practitioners (NHG). Anaemia guideline. Available via nhg.org.
- Thuisarts.nl. I have a vitamin B12 deficiency. Dutch College of General Practitioners. Available via thuisarts.nl.
Every blood test result through Lunara includes a professional assessment by a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
الوسوم
الكاتب
