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If fatigue does not go away despite sleep, or if your hands are tingling without a clear explanation, many people first think of stress, iron deficiency, or a lack of recovery. However, signs of B12 deficiency can come on insidiously, causing both anemia and effects on the nervous system. For those who eat little animal-based food, use certain medications, or have gastrointestinal problems, the question is especially relevant.
Signs of B12 deficiency – foods and recipes that contain vitamin B12
Vitamin B12, also known as cobalamin, is needed for the body to form red blood cells, for cellular metabolism, and for the proper function of the nervous system. A deficiency can therefore manifest as both classic symptoms of anemia and neurological disorders—meaning symptoms affecting the nerves and brain. The body stores relatively large amounts of B12, which means a deficiency can sometimes develop slowly over several years.
Signs of B12 deficiency that many people miss
Common signs of B12 deficiency are fatigue, lack of energy, dizziness, headache, palpitations and shortness of breath. Some people notice that their concentration deteriorates or that it becomes more difficult to stay focused during the workday. If the deficiency has led to anemia, the symptoms are partly due to the body's tissues receiving a poorer oxygen supply.
B12 deficiency can also cause symptoms in the mucous membranes and the nervous system. The tongue can become sore, red, and inflamed, with a completely smooth surface. Some people experience numbness, tingling, or reduced sensation in their hands and feet. In more pronounced cases of deficiency, balance can deteriorate, memory can be affected, and depressive symptoms or low mood may occur. Neurological symptoms can manifest even without clear signs of anemia, which is a key reason why B12 deficiency is sometimes missed in its early stages.
A typical everyday example is a person seeking help for "unexplained energy deficiency," where the root problem is actually not just about sleep or workload. Another is an elderly person who begins to feel unsteady on their feet, or individuals on a vegan diet who find that their recovery has worsened, even though their diet otherwise feels adequate. Both situations may justify testing, especially if the symptoms are combined with known risk factors.
Why does B12 deficiency occur even though you eat quite well?
B12 deficiency is not always due to an insufficient dietary intake of the vitamin. A common cause is impaired absorption in the stomach or intestines. To absorb B12, the body requires a protein called intrinsic factor; in cases of pernicious anemia, this system functions poorly. Deficiencies can also be seen after certain gastrointestinal surgeries or due to diseases that affect absorption.
Medications are another common explanation. Long-term treatment with metformin or acid-suppressing drugs, such as proton pump inhibitors (PPIs), can increase the risk of B12 deficiency. Nitrous oxide (laughing gas) can also contribute to functional B12 deficiency, which is an important factor to be aware of in both younger and older patients.
Diet, of course, plays a major role. Vitamin B12 is found primarily in animal products such as fish, meat, shellfish, eggs, milk, and cheese. For vegans, supplements or adequate amounts of fortified products are necessary, since plant-based foods often lack active B12 in a biologically usable form. Lacto-ovo vegetarians get B12 through dairy products and eggs, but their intake may still be too low if these foods are consumed sparingly.
Foods containing vitamin B12
The foods richest in B12 are often animal products. Fish and shellfish are particularly good sources, but meat, eggs and dairy products also contribute. Liver contains very high amounts, but does not need to be the basis of the diet to get enough.
Examples of foods that contain vitamin B12:
Fish such as salmon and cod
Shellfish and mussels
Beef, lamb and other meats
Liver and liver pâté
Milk, yoghurt and cheese
Eggs
Fortified vegetable drinks and plant-based alternatives, if they are actually B12-fortified
For those eating a plant-based diet, it is wise to read the ingredients list instead of assuming that all oat, soy, or rice drinks contain B12. Some are fortified, while others are not. This makes a major difference in practice, especially if you consume these products daily and assume they automatically cover your requirements.
Simple recipe ideas with vitamin B12 in everyday life
Advanced cooking is rarely necessary to get more B12 into your diet. The key is to choose ingredients that naturally contain the vitamin and make them a recurring part of your week. However, for individuals with a confirmed deficiency, dietary changes are not always enough—especially if absorption is impaired.
Here are some simple recipe ideas that fit into everyday life:
Baked salmon with potatoes and yogurt sauce: salmon contributes B12, and the yogurt sauce provides an extra supplement.
Omelette with cheese and spinach: eggs and cheese make the dish B12-rich and easy to make as a quick lunch.
Fish stew with cod and saffron: cod is a good source, and the stew works for the whole family or as a lunch box.
Meat sauce with ground beef and whole grain pasta: a practical alternative for those who want to increase their intake through everyday food.
Overnight oats or smoothie with enriched plant drink: a useful alternative for vegans, provided that the product is truly enriched with B12.
When is food not enough – and when should you test your levels?
If a B12 deficiency is purely due to low dietary intake, adjusting your diet can sometimes be part of the solution. However, if the root cause is reduced absorption in the stomach or intestines, treatment with high-dose supplements or injections is often required based on a medical assessment.
Blood testing is highly relevant for symptoms such as fatigue, numbness, tingling, unsteadiness, impaired concentration, or recurrent anemia. Indications for testing also exist for individuals on a vegan diet, those who have undergone stomach or intestinal surgery, those on long-term metformin or antacid therapy, and patients with diseases affecting intestinal absorption. For a more complete clinical picture, B12 analyses are often supplemented with other tests, such as a complete blood count (CBC), folate, homocysteine, or methylmalonic acid (MMA).
Since the ongoing use of dietary supplements can affect blood levels and complicate the interpretation of test results, any intake of over-the-counter preparations should always be reviewed prior to an investigation. Normal B12 values in a patient who is already taking supplements do not necessarily rule out a functional deficiency if symptoms persist.
B12 deficiency often causes early but highly non-specific symptoms. Identifying the deficiency at an early stage is crucial to prevent long-term complications and permanent neurological damage. Testing is therefore used both to establish a potential deficiency and to differentiate the condition from other differential diagnoses, such as iron deficiency, folate deficiency, or thyroid disorders.
