Lately you lose things more often: your keys, a name, the thread of a conversation. Your feet sometimes feel tingly and you are tired in a way that does not lift with a weekend of rest. You put it down to your age or your busy job. But this list of symptoms can also fit something simple and easy to measure: a vitamin B12 deficiency.
Precisely because the symptoms overlap so much with stress and sleep loss, B12 is a classic missed cause in men. No one thinks of a vitamin when they are forgetful, and that is exactly why it often goes unnoticed for too long.
Which symptoms fit a B12 deficiency?
Besides tiredness there can be neurological symptoms: tingling, a numb feeling in hands or feet, reduced concentration, forgetfulness and sometimes an unsteady gait. A long-standing deficiency can also cause anemia. A low vitamin B12, and sometimes additionally the active vitamin B12, shows whether something is going on here.
The neurological symptoms are the most important to take seriously. The Dutch College of General Practitioners (NHG) stresses that tingling and a numb feeling are a reason not to wait too long, because long-term nerve damage does not always fully recover.
Who is more at risk of a deficiency?
The table below helps you gauge whether you belong to a group at increased risk. If you do and you have symptoms, testing is all the more worthwhile.
| Situation | Why this raises the risk | What you can do |
|---|---|---|
| Little or no animal products | B12 is mainly in meat, fish, egg and dairy | Supplement deliberately, get your value measured |
| Vegetarian or vegan diet | Plant food provides barely any B12 | Consider fortified products or a supplement |
| Stomach or bowel problems | Absorption of B12 can be disrupted | Discuss testing with your GP |
| Long-term certain stomach medication | Can reduce the absorption of B12 | Check periodically with your doctor |
Where does a deficiency come from?
A deficiency arises from too little intake or from reduced absorption. The Netherlands Nutrition Centre (Voedingscentrum) points out that B12 is almost only in animal products: meat, fish, egg and dairy. If you eat little of these, the risk of a deficiency is greater. Vegetarians and vegans often already pay attention to this, and yet we still regularly see a low value in them too, because the need is easily underestimated.
With absorption problems it is different: you may eat enough, but your body does not absorb the B12 well. That is more common with stomach or bowel conditions and with long-term use of certain acid reducers.
How much do you need?
The Health Council of the Netherlands (Gezondheidsraad) gives nutritional norms for vitamin B12 that for most adult men are around a few micrograms a day. A varied diet with animal products usually reaches that easily. The tricky part is not the amount in your food, but whether your body also absorbs it well.
Your body also stores B12 for a long time, mainly in your liver. As a result, it can take years before a deficiency builds up and causes symptoms, even if your intake has been too low for a while. That explains why someone who has just switched to a plant-based diet often has no symptoms yet, while the longer-term risk does rise.
What does a regular B12 say versus the active B12?
A standard blood test measures the total vitamin B12 in your blood. The downside is that this value can sometimes look normal while something is going on, because not all measured B12 is actually usable by your cells. The active vitamin B12, also called holotranscobalamin, gives a more targeted picture of the part your body can really use.
In practice a doctor looks at the whole: your symptoms, your values and sometimes additional measurements. So you discuss a borderline case in consultation with your GP, not on the basis of one number.
What do you do with a low result?
Discuss a low value with your GP. They can check whether it is due to your diet or your absorption, and what is appropriate: adjusting your diet, tablets or injections. Topping up on a hunch without knowing the cause is rarely a good idea. If you have tingling or a numb feeling, do not wait too long with it. The fatigue can improve fairly quickly after topping up, while neurological symptoms sometimes need more time to recover, and not always fully.
If you want the broader picture, read our pillar always tired as a man, or the piece on vitamin D deficiency, which also often sits behind fatigue.
The B-Vitamins panel maps out your B vitamins, and the Complete Men’s Health Panel looks more broadly at your energy.
Sources
- NHG (Dutch College of General Practitioners). Anemia guideline: vitamin B12 and management.
- Gezondheidsraad (Health Council of the Netherlands). Nutritional norms for vitamin B12.
- Voedingscentrum (Netherlands Nutrition Centre). Vitamin B12: sources and function in the diet.
Disclaimer
Caliberhealth works with BIG-registered doctors who review your blood results. This article provides general information and is not a substitute for medical advice from a GP or specialist. A blood test is a tool, not a diagnosis in itself. For serious or persistent symptoms, contact your GP, or call 112 in an emergency.
Author
Caliberhealth
Dr. Naimi, BIG-registered physician, oversees the medical standards behind our content and assessments. Read our medical policy
