to overview Vitamins
Occurrence and structure
Most plentifully Folsäure is in vegetable materials such as spinach, asparagus sheet salads and grain, as well as in animal liver. It consists of three components: Pteridinsäure, Benzoesäure and Glutamat. Vitamin B9 is further contained in: Beet, brocolli, carrots, asparagus, Brussels sprouts, egg yolk, tomatoes and nuts
Function
Before folic acid (vitamin B9) can fulfill its functions in the body, it must be activated. This is done with the help of (dihydro)folate reductase, which converts it into the active tetrahydrofolate (i.e. folic acid + four H atoms). After its activation, tetrahydrofolate (FH4) serves as a carrier of C1 groups, i.e. of one C atom each, to which various substituents can be attached.
For example, CH4 or CH3OH. Tetrahydrofolate is particularly important in the synthesis of dTMP (deoxy thymidine monophosphate), a building block for DNA synthesis. This reaction is clinically very relevant because it is also carried out by tumor cells so that they can replicate their genetic material.
In tumor therapy, so-called dihydrofolate reductase inhibitors are therefore used, which – as the name suggests – restrict the function of dihydrofolate reductase to such an extent that it is no longer able to activate folic acid (vitamin B9) to form tetrahydrofolate. For example, dTMP, the DNA building block, can no longer be produced and thus the DNA can no longer be doubled, which leads to a halt in the growth of the affected cells. These inhibitory drugs therefore have a cytostatic effect (inhibiting the growth of tumor cells).
Methotrexate is one of these drugs. As far as folic acid is concerned, it can also have a clinical effect on bacterial metabolism. In contrast to humans, bacteria can synthesize folic acid/vitamin B9 themselves.
Humans take advantage of this to combat them by inhibiting this synthesis of folic acid with the help of sulfonamides. This inhibits the reproduction of bacteria. Sulfonamides thus serve as drugs for antibiotic therapy.
Since folic acid/vitamin B9 is essential for cell reproduction (mitosis), cells that divide frequently suffer from a deficiency. This is especially true for cells of the bone marrow, which are used for blood formation, among other things. Thus, a folic acid deficiency leads to so-called megaloblastic anemia (i.e. anemia in which the red blood cells = erythrocytes are enlarged = megalo).
It is essential to ensure sufficient folic acid intake, especially in pregnant women, since a folic acid deficiency is probably causally related to neural tube defects (i.e. defects in the child’s brain or spinal cord). More about folic acid during pregnancy from our partner. Water-soluble (hydrophilic) vitamins: Fat-soluble (hydrophobic) vitamins:
- Vitamin B1 – thiamine
- Vitamin B2 – Riboflavin
- Vitamin B3 – Niacin
- Vitamin B5 – pantothenic acid
- Vitamin B6 – PyridoxalPyridoxinPyridoxamine
- Vitamin B7 – biotin
- Vitamin B9 – folic acid
- Vitamin B12 – cobalamin
- Vitamin A – Retinol
- Vitamin C – Ascorbic acid
- Vitamin D – Calcitriol
- Vitamin E – tocopherol
- Vitamin K – PhylloquinoneMenachinone