B vitamins

What are they?

All B vitamins are water-soluble, dissolve in water and are not stored by our body. It is possible that we hear generic talk about vitamin B, but in reality under this name fall several distinct vitamins. They include:

• B1 (thiamine)
• B2 ( riboflavin )
• B3 ( Niacin )
• B5 (pantothenic acid)
• B6 (pyridoxine)
• B8 ( Biotin )
• B9 (folic acid)
• B12 (cobalamin).

Food sources

B vitamins are found in many frequently consumed foods, but especially in those of animal origin. Especially: Medicines ( laxatives , oral contraceptives , acetylsalicylic acid, antibiotics ), coffee, smoking and alcohol can reduce the body’s absorption or use of vitamins.The deficiencies of the vitamins of group B manifest themselves above all in the nervous tissue and in all the tissues in evolution.

To ensure adequate nutrition and a sufficient intake of all the B vitamins that the body needs, it is therefore necessary to follow a varied diet that includes both foods of vegetable origin (in particular products based on whole grains – bread, pasta, rice, flour – wheat germ, vegetables, peas, soy and legumes, potatoes, dried fruit – nuts, almonds and hazelnuts – and seeds) and foods of animal origin (beef and pork, fish, eggs, dairy products).

In addition, some fortified foods (e.g. breakfast cereals to which vitamins and minerals have been specially added) are also good sources of B vitamins.

However, it must be remembered that since these are water-soluble compounds, the vitamins of group B can be easily lost during cooking in water, for example during boiling tags. For this reason, in order to take good quantities of it, it is useful to pay attention to the preparation of some foods such as green leafy vegetables, especially avoiding prolonged cooking in water.

At the same time, we must not forget the more general principles of a healthy and balanced diet: among carbohydrates, Complex ones are preferable to simple sugar, the consumption of meat should be limited, alternating it with that of legumes and other sources of Protein animals (such as eggs and cheeses) and you should eat at least 5 portions of fruit and vegetables every day, which in addition to vitamins also provide minerals, fibers and antioxidant substances allied to health.

Absorption

The reduced availability may also be due to a malabsorption disorder in the stomach and intestines (subjects who have undergone surgery or suffer from chronic and inflammatory bowel diseases).

Among the different forms of vitamin B, from the point of view of absorption, vitamin B12 has peculiar characteristics. In fact, inside food, this vitamin binds in a non-specific way to proteins, from which, once in the stomach, it separates due to the high acidity typical of the gastric environment; however, vitamin B12 released in the stomach is bound by other proteins characterized by a high affinity for this molecule precisely in conditions of high acidity.

The passage into the duodenum, where the pH increases and where pancreatic enzymes are present, leads to the release of vitamin B12 and its binding with the intrinsic factor, which stabilizes it and allows it to reach the ileum, the terminal part of the small intestine where its absorption takes place.

B12 is the only water-soluble vitamin that can be stored in the body; In particular, about 3 mg are stored, of which 1 is in the liver.

In other cases the absorption process is simpler and there are no forms of storage. , for example, is absorbed and transported thanks to the action of receptors, but there are no molecules equivalent to the intrinsic factor that deal with stabilizing it; Its absorption begins already in the jejunum (the central part of the small intestine).

Effects

In general, B vitamins are involved as coenzymes (i.e. they promote the functions of enzymes) in almost all metabolic and food transformation processes, thus allowing the use of sugars, fats and proteins to obtain energy.Therefore, they become fundamental in the harmonious development of all the structures of the organism, including the nervous tissue, and especially in the age of growth.

In particular, vitamin B12 contributes to normal homocysteine metabolism tags. Indeed, it Indeed, it seems that it is necessary for the functioning of the enzyme methionine synthase, which allows the conversion of homocysteine into methionine, which in turn participates in the synthesis of another molecule (S-adenosylmethionine) involved in many biological reactions, including modifications of DNA and RNA.

Vitamin B9 (folic acid), in particular tetrahydrofolate, the active form of which folic acid is a precursor, is also necessary for the functioning of methionine synthase.

The other activities for which the involvement of group B vitamins has been demonstrated are summarized in the following table.

If you want to know the benefits of group vitamins for those who do sports read this article.

Shortage

In addition to neurological manifestations (such as those resulting from the loss of myelin tracts – the substance that surrounds nerves and allows rapid transmission of nerve impulses – or pathologies due to alterations in the levels of growth factors and other substances involved in communication between cells), in particular vitamin B12 deficiency causes a disease called pernicious anemia, that is, a severe lack of red blood cells.

Pernicious anemia is different from iron deficiency anemia. It is also referred to as megaloblastic anemia because red blood cells become much larger than normal tags. Cobalamin is not the only B vitamin associated with this disorder: even a lack of vitamin B9 (folic acid) can lead to the onset of this form of anemia, while a body deficient in vitamin B2 can suffer consequences for the skin (tongue, mouth, ear and cheek lesions), red eyes, dizziness, weight loss and hair loss.

In megaloblastic anemia, the enzyme methionine synthase is involved. The appearance of the disease may in fact be due to a reduction in its activity or a lack of tetrahydrofolate, which may compromise the maturation of the DNA; in addition, the decrease in methionine synthase activity can lead to the accumulation of 5-methyl-tetrahydrofolate which cannot be used for the synthesis of methionine and which cannot be converted into tetrahydrofolate.

However, the causes of megaloblastic anemia can also be other than vitamin B12 or B9 deficiency, and include taking certain medicines, infections and problems with the bone marrow.

Furthermore, vitamin B9 deficiency is particularly dangerous during pregnancy, when it can be associated with the appearance of defects in the development of the fetus, especially its nervous system.

If you want to learn more about B vitamins deficiencies, read this article .

Integration

In the presence of certain diseases, alcoholism, a diet that excludes foods of animal origin (such as that followed by strict vegetarians and the vegan diet), or conditions of increased need, such as growth, pregnancy, intense sporting activity , convalescence is indicated to resort to supplements.

In particular, vitamin B12 can be taken in the form of Cyanocobalamin , a molecule which is rapidly converted into the active form. In this way it is possible to effectively combat megaloblastic anemia, even if the risk of potassium deficiencies and cardiac complications associated with anemia remains during therapy.

Vitamin B9 deficiency can also be effectively counteracted by taking supplements, particularly indicated during pregnancy. The recommended daily dose for an adult is normally 400 micrograms, rising to 600 during pregnancy and 500 during breastfeeding.

Vitamin B supplements on the market can also provide other useful nutrients. Some, for example, contain magnesium ; others combine some B vitamins with omega 3, the fats naturally present in fish such as salmon and tuna allies of both cardiovascular health and nervous system development during pregnancy.

Furthermore, some essential oils, such as lemon oil, are also proposed as sources of vitamin B. Before using them, especially when their internal use is recommended, it is advisable to consult your doctor.

Precautions

Since these are water-soluble vitamins there is no overdose problem , since generally the excess dose that is not used by the body is expelled in the urine.