Week 5.2 Water-soluble vitamins
Water-soluble vitamins: members of B-complex + vitamin C
Divided based on general function:
- Energy releasing
- Blood cell forming
The B vitamins work closely together makes it hard to tell which individual B vitamin is missing
when deficiency occurs.
Metabolism: all chemical reactions involved in maintaining the living state of cells and organism/
Catabolism: breakdown of carbohydrates, proteins and fat to produce energy.
Anabolism: building up of components
Main functions B vitamins :
- Are the coenzymes in catabolic reactions.
- Are needed for healthy nerve conduction and thus muscle action
- Are needed for synthesis of neurotransmitters e.g. acetylcholine, serotonin and dopamine.
- Are indispensable for synthesis of fats used in the myelin sheaths of nerve cells
- Help to convert amino acids to make up proteins
Amino acids are converted from one to another to prepare for energy production or to make non-
essential amino acids.
Vitamin C – ascorbic acid
Vitamin C content in food may be reduced by prolonged storage and by cooking (destroyed by heat).
Functions of vitamin C:
- Antioxidant: it can neutralize free radicals by donating electrons. After giving up electrons,
vitamin C can accept them again to become reactivated. vitamin C protects water-soluble
molecules against oxidative damage (vitamin E does it for fat-soluble molecules).
- Coenzyme:
o Part of synthesis of collagen which gives structure to connective tissue.
o Role in the synthesis of several peptide hormones and neurotransmitters
o Needed for the production of bile acids
Deficiency early symptoms are very general and could indicate other diseases.
Severe deficiency: scurvy weakening of connective tissue
Smokers have lower plasma and white blood cell vitamin C levels than non-smokers, due to increased
oxidative stress.
Smokers need more vitamin C than non smokers
RDA for vitamin C for adults is 80 milligram.
, Feeding infants with breast milk or infant formula is good for sufficient vitamin C. Feeding them with
cow’s milk is not recommended, because it contains only little vitamin C and heat can destroy vitamin
C.
People with limited food variety are at risk for vitamin C deficiency.
When consuming too much vitamin C, no serious adverse effects occur. Complaints can be
gastrointestinal disturbances due to the osmotic effect of unabsorbed vitamin C in the GI tract.
Evidence that a particular intake of vitamin C has any clinical benefits is lacking, other than
preventing scurvy.
Vitamin C is required for the hydroxylation of specific amino acids that are part of the structural
protein collagen.
Folate (B9)
Folate is a term for a group of water-soluble B vitamins.
Folate antagonists: aminopterin and methotrexate.
Used for fortification (especially folic acid) of food products prevents chronic diseases, certain
cancers and birth defects.
basic back bone
The 5 different derivatives differ in presence of side groups.
Often presence of a methyl group
Also a certain number of glutamate groups
The glutamate groups need to be removed to leave only one glutamate in order for folate to be
absorbed.
These monoglutamate folates are actively absorbed by intestinal cells. Inside the intestinal cells, the
monoglutamate folates are converted into folates containing multiple glutamate groups prevents the
vitamin from being pumped out of the cell.
Folate is transported to tissues, including liver mainly as monoglutamate in the plasma bound to
plasma proteins.
The folates are taken up by tissue by same process as in intestinal cells specific transport proteins.
Most important is the capacity of folates to accept or donate methyl groups required for basal
physiological functions:
- Conversion of amino acids
- Creation of red blood cells
- Regulation of gene activity
- DNA and RNA synthesis
- DNA methylation
Water-soluble vitamins: members of B-complex + vitamin C
Divided based on general function:
- Energy releasing
- Blood cell forming
The B vitamins work closely together makes it hard to tell which individual B vitamin is missing
when deficiency occurs.
Metabolism: all chemical reactions involved in maintaining the living state of cells and organism/
Catabolism: breakdown of carbohydrates, proteins and fat to produce energy.
Anabolism: building up of components
Main functions B vitamins :
- Are the coenzymes in catabolic reactions.
- Are needed for healthy nerve conduction and thus muscle action
- Are needed for synthesis of neurotransmitters e.g. acetylcholine, serotonin and dopamine.
- Are indispensable for synthesis of fats used in the myelin sheaths of nerve cells
- Help to convert amino acids to make up proteins
Amino acids are converted from one to another to prepare for energy production or to make non-
essential amino acids.
Vitamin C – ascorbic acid
Vitamin C content in food may be reduced by prolonged storage and by cooking (destroyed by heat).
Functions of vitamin C:
- Antioxidant: it can neutralize free radicals by donating electrons. After giving up electrons,
vitamin C can accept them again to become reactivated. vitamin C protects water-soluble
molecules against oxidative damage (vitamin E does it for fat-soluble molecules).
- Coenzyme:
o Part of synthesis of collagen which gives structure to connective tissue.
o Role in the synthesis of several peptide hormones and neurotransmitters
o Needed for the production of bile acids
Deficiency early symptoms are very general and could indicate other diseases.
Severe deficiency: scurvy weakening of connective tissue
Smokers have lower plasma and white blood cell vitamin C levels than non-smokers, due to increased
oxidative stress.
Smokers need more vitamin C than non smokers
RDA for vitamin C for adults is 80 milligram.
, Feeding infants with breast milk or infant formula is good for sufficient vitamin C. Feeding them with
cow’s milk is not recommended, because it contains only little vitamin C and heat can destroy vitamin
C.
People with limited food variety are at risk for vitamin C deficiency.
When consuming too much vitamin C, no serious adverse effects occur. Complaints can be
gastrointestinal disturbances due to the osmotic effect of unabsorbed vitamin C in the GI tract.
Evidence that a particular intake of vitamin C has any clinical benefits is lacking, other than
preventing scurvy.
Vitamin C is required for the hydroxylation of specific amino acids that are part of the structural
protein collagen.
Folate (B9)
Folate is a term for a group of water-soluble B vitamins.
Folate antagonists: aminopterin and methotrexate.
Used for fortification (especially folic acid) of food products prevents chronic diseases, certain
cancers and birth defects.
basic back bone
The 5 different derivatives differ in presence of side groups.
Often presence of a methyl group
Also a certain number of glutamate groups
The glutamate groups need to be removed to leave only one glutamate in order for folate to be
absorbed.
These monoglutamate folates are actively absorbed by intestinal cells. Inside the intestinal cells, the
monoglutamate folates are converted into folates containing multiple glutamate groups prevents the
vitamin from being pumped out of the cell.
Folate is transported to tissues, including liver mainly as monoglutamate in the plasma bound to
plasma proteins.
The folates are taken up by tissue by same process as in intestinal cells specific transport proteins.
Most important is the capacity of folates to accept or donate methyl groups required for basal
physiological functions:
- Conversion of amino acids
- Creation of red blood cells
- Regulation of gene activity
- DNA and RNA synthesis
- DNA methylation
