Foods rich in vitamin B12 are especially those of animal origin, such as fish, meats, eggs and milk derivatives, and it performs functions like the maintenance nervous system metabolism, the formation of DNA and the production of healthy red blood cells for the blood, preventing anemia.
Vitamin B12 is not present in foods of plant origin, unless they are fortified with it, that is, B12 is artificially added in products such as soy and morning cereals. Therefore, people on a vegan diet should be aware of B12 consumption through fortified foods or through the use of supplements.
List of foods rich in vitamin B12
Some examples of foods rich in vitamin B12 are:
|Foods that contain vitamin B12||Amount of vitamin B12 in 100 g|
|Cooked liver steak||112 mcg|
|Steamed seafood||99 mcg|
|Cooked oysters||27 mcg|
|Cooked chicken liver||19 mcg|
|Cooked heart||14 mcg|
|Cooked herring||10 mcg|
|Cooked crab||9 mcg|
|Cooked salmon||2,8 mcg|
|Grilled trout||2,2 mcg|
|Cooked chicken||0,4 mcg|
|Cooked meat||2,5 mcg|
Vitamin B12 is present in nature in very small amounts, and so it is measured in micrograms, which is 1000 times less than a milligram. It is recommended that healthy adults consume about 2.4 mcg a day.
Vitamin B12 is absorbed in the intestine and stored mainly in the liver. Therefore, the liver can be considered one of the main dietary sources of vitamin B12.
Sources of vitamin B12 and intestinal absorption
Vitamin B12 exists in various forms and is usually bound to the cobalt mineral. This set of B12 sources are called cobalamin, with methylcobalamin and 5-deoxyadenosylcobalamin being the vitamin B12 found active in the human metabolism.
To be well absorbed by the intestine, vitamin B12 needs to be detached from proteins and this is done by the gastric juice found in the stomach. After this process, it is absorbed at the end of the ileum along with the intrinsic factor, substance produced by the stomach.
People at risk of vitamin B12 deficiency
It is estimated that about 10% to 30% of elderly people can not adequately absorb vitamin B12, and it is necessary to use vitamin B12 capsules to prevent problems such as anemia and malfunctioning of the nervous system.
In addition, people who have undergone bariatric surgery or who use medication that reduce stomach acidity, such as Omeprazole and Pantoprazole, also have impaired vitamin B12 absorption.
Vitamin B12 and Vegetarians
People with a vegetarian diet have difficulty consuming adequate amounts of vitamin B12. However, vegetarians who include eggs and dairy products in their diet tend to maintain good levels of B12 in the body, not needing supplementation.
On the other hand, vegans usually need to take supplements of B12, in addition to increasing the consumption of cereals such as soy and derivatives fortified with this vitamin. Food fortified with B12 will have this indication on the label, showing the amount of vitamin in the nutritional information of the product.
It is important to remember that the results of a blood test are not always a good B12 meter because it may be normal in the blood but deficient in the cells of the body. In addition, since vitamin B12 is stored in the liver, it may take about 5 years for a person to begin to have vitamin D deficiency symptoms or until the tests have changed results because the body will initially consume B12 previously stored.
Recommended amount of vitamin B12
The recommended amount of vitamin B12 varies according to age, as shown below:
- From 0 to 6 months of life: 0.4 mcg
- From 7 to 12 months: 0.5 mcg
- From 1 to 3 years of age: 0.9 mcg
- From 4 to 8 years of age: 1.2 mcg
- From 9 to 13 years old of age: 1.8 mcg
- From 14 years old and up: 2.4 mcg
Along with other nutrients like iron and folic acid, vitamin B12 is essential in preventing anemia.
Excess vitamin B12
Excess vitamin B12 in the body can cause small changes in the spleen, altered lymphocytes and increased lymphocytes. This is not very common because vitamin B12 is well tolerated by the body, but it can occur if the individual takes vitamin B12 supplements without medical orientation.