Vitamin B12, or cobalamin, is an essential nutrient for the formation of blood cells, preventing megaloblastic anemia, a disease that is caused by vitamin B12 deficiency.
Furthermore, vitamin B12 is also essential for the development and maintenance of the functions of the central nervous system, and for the metabolism of proteins and carbohydrates in food, helping to maintain good physical and mental disposition.
Vitamin B12 is found in foods of animal origin, such as eggs, milk, liver, fish and chicken. In addition, it can also be found in fortified foods or supplements, in the form of capsules, tablets, drops or injections, which are only indicated in cases of deficiency.
What is vitamin B12 for?
Vitamin B12 helps perform several functions in the body, including:
1. Maintain heart health
Vitamin B12 helps maintain heart health, as adequate levels of this nutrient in the body can prevent an increase in homocysteine levels in the blood, an amino acid that, in large quantities, can cause changes in blood vessels, favoring the emergence of diseases such as stroke, thrombosis or heart attack, for example.
2. Prevent megaloblastic anemia
By regulating the formation of blood cells, vitamin B12 helps prevent megaloblastic anemia, a type of anemia in which the bone marrow produces larger than normal red blood cells and a decrease in the size of white blood cells and platelets.
3. Maintain the health of neurons
Vitamin B12 helps maintain the health of neurons, because it participates in maintaining the functions of cells in the central nervous system, in addition to balancing homocysteine levels in the body, an amino acid that, in large quantities, is related to greater occurrences of Alzheimer’s disease, dementia and cognitive decline.
4. Act in the formation of DNA
Vitamin B12, together with vitamin B9, acts in the formation of genetic material (DNA and RNA), and in the expression of genes, being fundamental for the production of proteins, the development and functioning of the organism, and in the determination of physical and physiological characteristics.
Foods rich in vitamin B12
Vitamin B12 is found mainly in foods of animal origin, such as:
- Milk and dairy products;
- Red meat;
- Liver;
- Chicken;
- Fish;
- Seafood;
- Eggs.
Although they do not naturally contain vitamin B12, some plant-based foods, such as breakfast cereals, plant-based milks and brewer’s yeast, can be enriched with this vitamin, making them interesting options for those who follow a vegetarian diet.
How much vitamin B12 should I consume per day?
The recommended intake of vitamin B12 varies according to age, as indicated in the following table:
| Age | Recommended daily intake (mcg) |
| From 0 to 6 months | 0.4 mcg |
| From 6 to 12 months | 0.5 mcg |
| From 1 to 3 years | 0.9 mcg |
| From 4 to 8 years old | 1.2 mcg |
| From 9 to 13 years old | 1.8 mcg |
| Men and women from 14 years old | 2.4 mcg |
Additionally, pregnant women need to consume 2.6 mcg of vitamin B12 per day. The recommended daily intake for breastfeeding women is 2.8 mcg of vitamin B12.
Vitamin B12 test
The vitamin B12 test is normally indicated as a routine, being considered normal when the concentration of vitamin B12 in the blood is between 210.0 and 911.0 pg/mL.
The reference value for vitamin B12 can vary slightly from one laboratory to another, as different detection methods and equipment may be used to perform the test.
High Vitamin B12: What Can Cause It?
Vitamin B12 is considered high when the concentration of this vitamin is above 911.0 pg/mL of blood. High vitamin B12 in the body is a very rare condition, as the body normally eliminates excess of this vitamin through urine or sweat, even when taking supplements with high doses of this vitamin.
However, increased levels of vitamin B12 in the body may indicate the presence of certain diseases, such as cirrhosis, hepatitis, polycythemia vera or certain types of cancer, such as chronic myeloid leukemia. In these cases, it is advisable to consult a doctor to identify the cause of high vitamin B12 levels and thus indicate the most appropriate treatment.
Low vitamin B12: what it could be and what the symptoms are
Vitamin B12 is considered low when the concentration of the vitamin is less than 210.0 pg/mL. The main causes of low vitamin B12 are:
- Diet poor in foods rich in vitamin B12, such as meat, fish, eggs or dairy products;
- Pernicious anemia, due to decreased production of intrinsic factor, which is essential for the absorption of vitamin B12;
- Older age;
- Stomach or bowel reduction surgery;
- Crohn’s disease;
- Celiac disease.
Additionally, taking medications that block or neutralize the production of stomach acids, or that decrease the production of beneficial bacteria in the stomach and intestines, such as omeprazole and antibiotics, can also decrease vitamin B12 levels, which can cause symptoms such as numbness in the hands and feet and headache.
A lack of vitamin B12 can cause symptoms such as fatigue, shortness of breath, tingling in the hands and pale skin. In children, a deficiency of this vitamin can cause delayed development and growth.
A lack of vitamin B12 can cause the following symptoms:
- Loss of sensation and tingling in the hands, legs or feet;
- Frequent fatigue and weakness;
- Palpitations;
- Shortness of breathe ;
- Sores in the mouth and tongue;
- Memory loss and mental confusion;
- Loss of appetite;
- Eye twitching.
Which people are at greatest risk of low vitamin B12?
Some people who are at risk of vitamin B12 deficiency are:
- Strict vegetarians and vegans , as they do not consume foods of animal origin;
- Elderly people , due to the onset of pernicious anemia, which reduces the production of intrinsic factor, a protein that is important for the absorption of vitamin B12;
- People taking omeprazole and pantoprazole to reduce stomach acid;
- People with Roux-en-Y bariatric surgery ;
- People with digestive diseases , such as Crohn’s disease and celiac disease;
In these cases, it is necessary to use supplements of this vitamin to prevent problems such as anemia and malfunction of the nervous system, causing symptoms such as numbness, tingling and burning in the feet, stiffness and generalized weakness in the legs, depression and reasoning.
When to take vitamin B12 supplements?
Vitamin B12 supplements may be indicated when the intake of foods that are sources of this vitamin is low, as in the case of people who follow a vegetarian diet, or in situations where the body is unable to absorb the vitamin, as in cases of bariatric surgery, Crohn’s disease and celiac disease.
Supplementation with vitamin B12 in the form of oral or liquid supplements, or injectable, should always be prescribed by a doctor or nutritionist, after assessing the levels of this vitamin in the body, which is done through a blood or urine test.
16 foods rich in vitamin B12 (and recommended amount of each)
Foods rich in vitamin B12 are especially those of animal origin, such as fish, beef liver, crab, mussels, eggs and dairy products.
Vitamin B12 can also be found in plant-based foods when they are fortified with the artificial form of this vitamin, such as rice or oat milk, soy products and breakfast cereals, for example. Therefore, people who follow a vegan diet can consume vitamin B12 through fortified foods or by taking supplements.
Vitamin B12 plays very important roles in the body, such as maintaining metabolism, ensuring the health of the nervous system, stimulating the formation of DNA and participating in the production of healthy red blood cells.
16 foods rich in vitamin B12
The following table shows the amount of vitamin B12 in 100 g of each food:
| Food | Amount of vitamin B12 in 100g of food |
| 1. Grilled beef liver | 100 mcg |
| 2. Cooked mussels | 21 mcg |
| 3. Raw oysters | 14 mcg |
| 4. Cooked chicken liver | 21.1 mcg |
| 5. Cooked beef heart | 14 mcg |
| 6. Grilled sardines | 12 mcg |
| 7. Roasted herring | 9.6 mcg |
| 8. Boiled crab | 10.4 mcg |
| 9. Grilled salmon | 1.2 mcg |
| 10. Grilled trout | 2.2 mcg |
| 11. Mozzarella cheese | 1.7 mcg |
| 12. Whole cow’s milk | 0.8 mcg |
| 13. Boiled chicken egg | 0.5 mcg |
| 14. Boiled chicken | 0.3 mcg |
| 15. Grilled beef steak | 2 mcg |
| 16. Grilled tuna | 2.7 mcg |
Vitamin B12 plays an essential role in your health, from influencing energy production to protecting your nervous system. Ensuring you have adequate levels of this vitamin can make all the difference to your well-being.
If you have questions about your diet, supplements or want to know how to maintain a balanced diet that meets your needs, our nutritionists are ready to help.
Schedule an online consultation with Conexa right now and count on the support of specialists to take care of your health in a practical and personalized way. Don’t put off what can transform your quality of life today!
