Detailed knowledge on Vitamins
VITAMINS
The vitamins are generally divided into 2 major groups: fat-soluble and water-soluble. The fat-soluble vitamins, which are usually found associated with the lipids of natural foods, include vitamin A, D, E, and K. The vitamins of the B complex and vitamin C comprise the water-soluble group.
I. THE FAT-SOLUBLE VITAMINS
VITAMIN A
It was discovered by McCollum and Davis in 1915.
SOURCES
Fish liver oils, liver, butter, whole milk, and egg-yolk are foods of animal origin that supply preformed vitamin A (retinol). All pigmented (particularly yellow) vegetables and fruits (e.g., sweet potatoes, carrots, pumpkins, papayas, tomatoes, apricots, and peaches) and the leafy green vegetable supply provitamin A (carotene) in the diet. Carotenes are precursors to the vitamin in the animal body. ß-carotene has the highest vitamin A activity and is the most plentiful in human diets.) In man, the liver is believed to be the only organ capable of accomplishing the conversion of the carotenes to vitamin A.
FUNCTIONS
(1) The maintenance of the integrity of epithelial tissue is an important function of vitamin A. In its absence, the normal exterior epithelium is replaced by a dry, keratinized epithelium which is more susceptible to invasion by infectious organisms.
FUNCTIONS
The principal action of vitamin D is to increase the absorption of calcium and phosphorus from the intestine. The vitamin also has a direct effect on the calcification process.
DEFICIENCY
(1) Rickets in children. Slow growth, degenerate calcium metabolism, and deformed bones (e.g. bowlegs, knock-knees, rachitic rosary-a beaded appearance of the ribs and "pigeon breast").
(2) Osteomalacia (soft bones) in some adults, particularly in women during pregnancy.
TOXICITY OF VITAMIN D
Excessive quantities of vitamin D (ten times the normally required daily level) given over prolonged periods either to children or to adults produce demineralization of bone, and multiple fractures may occur after only minimal trauma. and phosphorus is both markedly elevated, resulting in metastatic Serum calcium calcification of many soft tissues and formation of renal calculi. The latter may block the renal tubules sufficiently to cause secondary hydronephrosis.
II. THE WATER-SOLUBLE VITAMINS
VITAMINS OF THE 'B' COMPLEX
THIAMINE (B1)
(Antiberiberi substance, Antineuritic factor)
The structure of thiamine, which was first isolated in crystalline form by Jansen and Windaus in 1926, was established by Williams and his coworkers in 1936.
SOURCES
The outer layers of the seeds of plants are especially rich in thiamine. Whole-wheat bread, therefore, is an excellent source, whereas ordinary white bread is a poor source of vitamin since most of the thiamine is removed in the milling process. Among the more abundant sources are unrefined cereal grains, legumes, brewer's yeast, liver, kidney, and lean cuts of pork. Excessive cooking leaches the water-soluble thiamine from many foodstuffs.
FUNCTIONS
It is a constituent of the coenzyme thiamine pyrophosphate (TPP) and is essential for carbohydrate metabolism (oxidative decarboxylation of pyruvate or of x-ketoglutarate). Thiamine deficiency causes Beriberi which was first described by Admiral Takaki in 1887 among Japanese sailors. The disease
is still an important public health problem in the Philippines, Vietnam, Thailand, and Burma where polished milled rice is a staple food. Beriberi affects predominantly the peripheral nervous system, the gastrointestinal tract, and the cardiovascular system. There are two forms of the disease: "dry" and "wet" beriberi. In the dry form, there is the rapid loss of weight and muscle wasting. Marked peripheral neurites and muscular weakness result in the patient's becoming almost helpless. Deep reflexes are lost, sensory changes may occur, and anxiety states and mental confusion are evident. The heart becomes enlarged. In wet beriberi, there is generalized edema that may obscure the weakness and muscular wasting. Acute cardiac symptoms may develop rapidly.
VITAMINS
RIBOFLAVIN(B2)
Warburg and Christian isolated this yellow enzyme from yeast in 1932.
SOURCES
Riboflavin is widely distributed throughout the plant and animal kingdom, with very rich sources in anaerobic fermenting. bacteria. Milk, liver, kidney, and heart are excellent sources. Many vegetables are also good sources, but the cereals are rather low in. riboflavin content.
FUNCTIONS
It is a constituent of two coenzymes-flavin mono-nucleotide (FMN), and flavin adenine dinucleotide (FAD), which are involved in intermediary metabolism. All known biological functions of riboflavin involve these two coenzymes.
DEFICIENCY
Riboflavin deficiency in man is characterized by a particular type of glossitis (magenta-colored tongue), fissures at the corners of the mouth and lips (cheilosis), localized seborrheic dermatitis of the face, and corneal vascularization.
NICOTINIC ACID OR NIACIN
(Pellagra preventing, PP, factor of Goldberger) The physician to Philip V of Spain. The identification of nicotinic acid Pellagra was recognized as early as 1735 by Gaspar Casal,
BIOCHEMIST as the responsible factor was made by Elvehjem, Woolley, their associates in 1937.
SOURCES
Niacin is found most abundantly in yeast. Lean meats live and poultry is good sources. Milk, tomatoes, canned salmon, several leafy green vegetables contribute sufficient amounts of the vitamin to prevent disease. The body can synthesize this vitamin from the amino acid tryptophan.
FUNCTIONS
It was discovered by McCollum and Davis in 1915.
SOURCES
Fish liver oils, liver, butter, whole milk, and egg-yolk are foods of animal origin that supply preformed vitamin A (retinol). All pigmented (particularly yellow) vegetables and fruits (e.g., sweet potatoes, carrots, pumpkins, papayas, tomatoes, apricots, and peaches) and the leafy green vegetable supply provitamin A (carotene) in the diet. Carotenes are precursors to the vitamin in the animal body. ß-carotene has the highest vitamin A activity and is the most plentiful in human diets.) In man, the liver is believed to be the only organ capable of accomplishing the conversion of the carotenes to vitamin A.
FUNCTIONS
(1) The maintenance of the integrity of epithelial tissue is an important function of vitamin A. In its absence, the normal exterior epithelium is replaced by a dry, keratinized epithelium which is more susceptible to invasion by infectious organisms.
(2) It is essential to growth, particularly of the skeleton and other connective tissue.
(3) It is a constituent of visual purple (rhodopsin), a photosensitive pigment of the rod cells of the retina. The specific role of vitamin A in the physiologic mechanisms of vision has been elucidated largely by Wald and Morton.
(4) It prevents infection. Deficiencies of Vitamin A
(a) Night blindness (nyctalopia), which is a disturbance of rod vision, is one manifestation of vitamin A deficiency.
(b) Xerophthalmia, i.e., Keratinization of ocular tissue, which may progress to blindness, is a late result of vitamin A deficiency. Xerophthalmia is a major cause of blindness in childhood. It is still a major health problem in many parts of the world, especially in Hong Kong, Manila, Saigon, and Dacca.
(c) In the absence of vitamin A, the growth of experimental animals does not progress normally. The skeleton is affected first, and then the soft tissues.
(d) In the growing animal, collagenous tissues are particularly affected by a deficiency of vitamin A.
TOXICITY OF VITAMIN A
Hypervitaminosis A may occur as the ministration of large doses (in the form of vitamin A concentrates) a consequence of the ad to infants and small children. The principal symptoms are painful joints, periosteal thickening of long bones, and loss of hair. Pre-formed vitamin A in large amounts may be toxic to adults as well as children.
VITAMIN D
Vitamins D are actually a group of compounds. All are sterols that occur in nature, chiefly in the animal organism. For nutritional purposes, there are 2 important D vitamins:
(i) D, (Activated Ergosterol; Ergocalciferol or Viosterol). It occurs in the plant kingdom (e.g., in ergot and in yeast).
(ii) D. (Activated 7-Dehydrocholesterol, Cholecalciferol 7-Dehydrocholesterol is the form in which provitamin D, is found in natural foods. Man and other mammals can synthesize pro vitamin D, in the body. The vitamin is then activated in the skin by exposure to ultraviolet rays and carried to various organs in the body for utilization or storage (in the liver)
(3) It is a constituent of visual purple (rhodopsin), a photosensitive pigment of the rod cells of the retina. The specific role of vitamin A in the physiologic mechanisms of vision has been elucidated largely by Wald and Morton.
(4) It prevents infection. Deficiencies of Vitamin A
(a) Night blindness (nyctalopia), which is a disturbance of rod vision, is one manifestation of vitamin A deficiency.
(b) Xerophthalmia, i.e., Keratinization of ocular tissue, which may progress to blindness, is a late result of vitamin A deficiency. Xerophthalmia is a major cause of blindness in childhood. It is still a major health problem in many parts of the world, especially in Hong Kong, Manila, Saigon, and Dacca.
(c) In the absence of vitamin A, the growth of experimental animals does not progress normally. The skeleton is affected first, and then the soft tissues.
(d) In the growing animal, collagenous tissues are particularly affected by a deficiency of vitamin A.
TOXICITY OF VITAMIN A
Hypervitaminosis A may occur as the ministration of large doses (in the form of vitamin A concentrates) a consequence of the ad to infants and small children. The principal symptoms are painful joints, periosteal thickening of long bones, and loss of hair. Pre-formed vitamin A in large amounts may be toxic to adults as well as children.
VITAMIN D
Vitamins D are actually a group of compounds. All are sterols that occur in nature, chiefly in the animal organism. For nutritional purposes, there are 2 important D vitamins:
(i) D, (Activated Ergosterol; Ergocalciferol or Viosterol). It occurs in the plant kingdom (e.g., in ergot and in yeast).
(ii) D. (Activated 7-Dehydrocholesterol, Cholecalciferol 7-Dehydrocholesterol is the form in which provitamin D, is found in natural foods. Man and other mammals can synthesize pro vitamin D, in the body. The vitamin is then activated in the skin by exposure to ultraviolet rays and carried to various organs in the body for utilization or storage (in the liver)
SOURCES
In its active form, vitamin D is not well distributed in nature, the only rich sources being the liver and viscera of fish and the liver of animals that feed on fish. Eggs and butter also contain vitamin D. Milk is a poor source of vitamin. Vitamin D is stable in foods; storage, processing, and cooking do not affect its activity.
FUNCTIONS
The principal action of vitamin D is to increase the absorption of calcium and phosphorus from the intestine. The vitamin also has a direct effect on the calcification process.
DEFICIENCY
(1) Rickets in children. Slow growth, degenerate calcium metabolism, and deformed bones (e.g. bowlegs, knock-knees, rachitic rosary-a beaded appearance of the ribs and "pigeon breast").
(2) Osteomalacia (soft bones) in some adults, particularly in women during pregnancy.
TOXICITY OF VITAMIN D
Excessive quantities of vitamin D (ten times the normally required daily level) given over prolonged periods either to children or to adults produce demineralization of bone, and multiple fractures may occur after only minimal trauma. and phosphorus is both markedly elevated, resulting in metastatic Serum calcium calcification of many soft tissues and formation of renal calculi. The latter may block the renal tubules sufficiently to cause secondary hydronephrosis.
VITAMIN E
In 1936 Evans and Emerson isolated vitamin E from wheat germ oil. It was given the nag of 13 phenol (Gk. todos, childbirth;phero, to bear; or, alcohol). There are 4 varieties of tocopherols: alpha, beta, gamma, and delta-tocopherol; of these, alpha-tocopherol has the widest distribution and greatest biological activity.
In 1936 Evans and Emerson isolated vitamin E from wheat germ oil. It was given the nag of 13 phenol (Gk. todos, childbirth;phero, to bear; or, alcohol). There are 4 varieties of tocopherols: alpha, beta, gamma, and delta-tocopherol; of these, alpha-tocopherol has the widest distribution and greatest biological activity.
SOURCES
The richest natural sources of tocopherol are toils, e.g. wheat germ, rice, cottonseed, as well as the lipids of green leaves. Fish-liver oils, rich in vitamins A and D, are devoid of tocopherol. Good sources of vitamin E include eggs, muscle meats, liver, fish, and chicken.
FUNCTIONS
(1) The most striking chemical characteristic of the vitamins E is their antioxidant property. Polyunsaturated fatty acids are easily attacked by molecular oxygen, resulting in the formation of peroxides. The tocopherols prevent this.
(2) It is required for the normal reproductive function in rats.
FUNCTIONS
(1) The most striking chemical characteristic of the vitamins E is their antioxidant property. Polyunsaturated fatty acids are easily attacked by molecular oxygen, resulting in the formation of peroxides. The tocopherols prevent this.
(2) It is required for the normal reproductive function in rats.
(3) In some animal species, a lack of vitamin E produces muscular dystrophy.
DEFICIENCY
The wide distribution of vitamin E in vegetable oils, cereal grains, and animal fats makes it unlikely that a deficiency of this nutrient occurs in normal humans.
VITAMIN K
Vitamin K (Koagulations vitamin) was identified in 1935 by Dam as a factor present in green leaves which prevented hemorrhage.
SOURCES
Vitamin K is present in alfalfa and in such dark green vegetables as spinach, cabbage leaves as well as in cauliflower and peas. Tomatoes, cheese, egg yolk, and liver are good sources. Fruits are poor sources, as are molds, yeast, and fungi.
FUNCTIONS
DEFICIENCY
The wide distribution of vitamin E in vegetable oils, cereal grains, and animal fats makes it unlikely that a deficiency of this nutrient occurs in normal humans.
VITAMIN K
Vitamin K (Koagulations vitamin) was identified in 1935 by Dam as a factor present in green leaves which prevented hemorrhage.
SOURCES
Vitamin K is present in alfalfa and in such dark green vegetables as spinach, cabbage leaves as well as in cauliflower and peas. Tomatoes, cheese, egg yolk, and liver are good sources. Fruits are poor sources, as are molds, yeast, and fungi.
FUNCTIONS
The best-known function of vitamin K is to catalyze the synthesis of prothrombin by the liver. It also regulates the synthesis of other plasma clotting factors dependent on vitamin K (factors VII, IX, and X).
DEFICIENCY
In the absence of vitamin K a hypoprothrombinemia in which blood clotting time may be greatly prolonged. In diet, the deficiency of vitamin K is not likely to occur since the vitamin is fairly well distributed in foods and the intestinal micro-organism synthesizes considerable vitamin K in the intestine. However, a deficiency may occur as a result of prolonged oral therapy with drugs capable of vitamin K-producing bacteria (Sulfaguanidine Furthermore, the absorption of vitamin K from the intestine depends on the presence of bile. A deficiency state will therefore result as a consequence of biliary tract obstruction or if there is a defect in fat absorption, such as in sprue and celiac disease.
DEFICIENCY
In the absence of vitamin K a hypoprothrombinemia in which blood clotting time may be greatly prolonged. In diet, the deficiency of vitamin K is not likely to occur since the vitamin is fairly well distributed in foods and the intestinal micro-organism synthesizes considerable vitamin K in the intestine. However, a deficiency may occur as a result of prolonged oral therapy with drugs capable of vitamin K-producing bacteria (Sulfaguanidine Furthermore, the absorption of vitamin K from the intestine depends on the presence of bile. A deficiency state will therefore result as a consequence of biliary tract obstruction or if there is a defect in fat absorption, such as in sprue and celiac disease.
II. THE WATER-SOLUBLE VITAMINS
VITAMINS OF THE 'B' COMPLEX
THIAMINE (B1)
(Antiberiberi substance, Antineuritic factor)
The structure of thiamine, which was first isolated in crystalline form by Jansen and Windaus in 1926, was established by Williams and his coworkers in 1936.
SOURCES
The outer layers of the seeds of plants are especially rich in thiamine. Whole-wheat bread, therefore, is an excellent source, whereas ordinary white bread is a poor source of vitamin since most of the thiamine is removed in the milling process. Among the more abundant sources are unrefined cereal grains, legumes, brewer's yeast, liver, kidney, and lean cuts of pork. Excessive cooking leaches the water-soluble thiamine from many foodstuffs.
FUNCTIONS
It is a constituent of the coenzyme thiamine pyrophosphate (TPP) and is essential for carbohydrate metabolism (oxidative decarboxylation of pyruvate or of x-ketoglutarate). Thiamine deficiency causes Beriberi which was first described by Admiral Takaki in 1887 among Japanese sailors. The disease
is still an important public health problem in the Philippines, Vietnam, Thailand, and Burma where polished milled rice is a staple food. Beriberi affects predominantly the peripheral nervous system, the gastrointestinal tract, and the cardiovascular system. There are two forms of the disease: "dry" and "wet" beriberi. In the dry form, there is the rapid loss of weight and muscle wasting. Marked peripheral neurites and muscular weakness result in the patient's becoming almost helpless. Deep reflexes are lost, sensory changes may occur, and anxiety states and mental confusion are evident. The heart becomes enlarged. In wet beriberi, there is generalized edema that may obscure the weakness and muscular wasting. Acute cardiac symptoms may develop rapidly.
VITAMINS
RIBOFLAVIN(B2)
Warburg and Christian isolated this yellow enzyme from yeast in 1932.
SOURCES
Riboflavin is widely distributed throughout the plant and animal kingdom, with very rich sources in anaerobic fermenting. bacteria. Milk, liver, kidney, and heart are excellent sources. Many vegetables are also good sources, but the cereals are rather low in. riboflavin content.
FUNCTIONS
It is a constituent of two coenzymes-flavin mono-nucleotide (FMN), and flavin adenine dinucleotide (FAD), which are involved in intermediary metabolism. All known biological functions of riboflavin involve these two coenzymes.
DEFICIENCY
Riboflavin deficiency in man is characterized by a particular type of glossitis (magenta-colored tongue), fissures at the corners of the mouth and lips (cheilosis), localized seborrheic dermatitis of the face, and corneal vascularization.
NICOTINIC ACID OR NIACIN
(Pellagra preventing, PP, factor of Goldberger) The physician to Philip V of Spain. The identification of nicotinic acid Pellagra was recognized as early as 1735 by Gaspar Casal,
BIOCHEMIST as the responsible factor was made by Elvehjem, Woolley, their associates in 1937.
SOURCES
Niacin is found most abundantly in yeast. Lean meats live and poultry is good sources. Milk, tomatoes, canned salmon, several leafy green vegetables contribute sufficient amounts of the vitamin to prevent disease. The body can synthesize this vitamin from the amino acid tryptophan.
FUNCTIONS
It is convertible into nicotinamide and thus functions met biologically as a component of the 2 coenzymes: nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). These coenzymes, which operate as hydrogen and electron transfer agents under reversible oxidation and reduction, play a vital role in metabolism, leading to the formation of ATP in the electron transport system (ETS).
DEFICIENCY
Pellagra was established as a deficiency disease by Gold Berger. The disease is symptomatized by three D's, namely diarrhea, dermatitis of those areas that are exposed to sunlight, and dementia, due to disturbances of the central nervous system. Stomatitis and glossitis are also associated with the other symptoms
Alcoholism causes deficiency of the vitamin and is an important precipitating factor of the disease.
PYRIDOXINE(B6) (Rat Antidermatitis Factor)
Pyridoxine was first discovered in 1938 and synthesized by Stiller in 1939. Natural sources contain two other forms of this vitamin, pyridoxal, and pyridoxamine. The three substances as a group are designated vitamin B.; no single one is considered the vitamin since all three are equally effective in animal nutrition.
SOURCES
The B6 group is widely distributed in nature, and those foods rich in other members of the B complex are excellent sources of these materials, e.g., the germs of various grains and seeds, egg yolk, yeast, and meat, particularly liver and kidney.
FUNCTIONS
(1) It is a constituent of coenzymes pyridoxal phosphate, which is involved in the non-oxidative degradation of amino acids, viz., transamination, deamination, decarboxylation, etc.
(2) It is essential in the synthesis of haem for hemoglobin and cytochromes.
DEFICIENCY
There is little evidence that diets containing a reasonable balance of naturally occurring foodstuffs are ever seriously deficient in vitamin B6. However, occasional cases of B6 deficiency do arise as a result of malabsorption, alcoholism, antagonism to drugs, etc. Pyridoxine deficiency in humans may be associated with a reversible hypochromic microcytic anemia with a high serum iron similar to that observed in pyridoxine-deficient animals.
PANTOTHENIC ACID
This factor was first recognized as a portion of the "bios" complex by R. J. Williams and his colleagues in 1933. The significance of this substance in animal nutrition was established by Jukes, Woolley, and their associates.
SOURCES
Pantothenic acid is widely distributed in food, particularly that from animal sources, whole grain cereals, and legumes. Excellent food sources include egg yolk, kidney, liver, and yeast. Lean leaf, skimmed milk, sweet potatoes, and molasses are fair sources. Royal jelly, prepared by the bee colony for the nutrition of the queen bee, and fish ovaries before spawning are the richest known sources of this vitamin.
DEFICIENCY
Pellagra was established as a deficiency disease by Gold Berger. The disease is symptomatized by three D's, namely diarrhea, dermatitis of those areas that are exposed to sunlight, and dementia, due to disturbances of the central nervous system. Stomatitis and glossitis are also associated with the other symptoms
Alcoholism causes deficiency of the vitamin and is an important precipitating factor of the disease.
PYRIDOXINE(B6) (Rat Antidermatitis Factor)
Pyridoxine was first discovered in 1938 and synthesized by Stiller in 1939. Natural sources contain two other forms of this vitamin, pyridoxal, and pyridoxamine. The three substances as a group are designated vitamin B.; no single one is considered the vitamin since all three are equally effective in animal nutrition.
SOURCES
The B6 group is widely distributed in nature, and those foods rich in other members of the B complex are excellent sources of these materials, e.g., the germs of various grains and seeds, egg yolk, yeast, and meat, particularly liver and kidney.
FUNCTIONS
(1) It is a constituent of coenzymes pyridoxal phosphate, which is involved in the non-oxidative degradation of amino acids, viz., transamination, deamination, decarboxylation, etc.
(2) It is essential in the synthesis of haem for hemoglobin and cytochromes.
DEFICIENCY
There is little evidence that diets containing a reasonable balance of naturally occurring foodstuffs are ever seriously deficient in vitamin B6. However, occasional cases of B6 deficiency do arise as a result of malabsorption, alcoholism, antagonism to drugs, etc. Pyridoxine deficiency in humans may be associated with a reversible hypochromic microcytic anemia with a high serum iron similar to that observed in pyridoxine-deficient animals.
PANTOTHENIC ACID
This factor was first recognized as a portion of the "bios" complex by R. J. Williams and his colleagues in 1933. The significance of this substance in animal nutrition was established by Jukes, Woolley, and their associates.
SOURCES
Pantothenic acid is widely distributed in food, particularly that from animal sources, whole grain cereals, and legumes. Excellent food sources include egg yolk, kidney, liver, and yeast. Lean leaf, skimmed milk, sweet potatoes, and molasses are fair sources. Royal jelly, prepared by the bee colony for the nutrition of the queen bee, and fish ovaries before spawning are the richest known sources of this vitamin.
FUNCTIONS
Coenzyme A, which is essential to several fundamental reactions in, In its active form, pantothenic acid is a constituent of metabolism. An example is a combination of coenzyme A with acetate to form acetyl-coenzyme A which participates in a number, of important metabolic processes like the citric acid cycle. Besides,acetyl-CoA is a precursor of cholesterol and thus of the steroid hormones.
Coenzyme A, which is essential to several fundamental reactions in, In its active form, pantothenic acid is a constituent of metabolism. An example is a combination of coenzyme A with acetate to form acetyl-coenzyme A which participates in a number, of important metabolic processes like the citric acid cycle. Besides,acetyl-CoA is a precursor of cholesterol and thus of the steroid hormones.
DEFICIENCY
Deficiency of Pantothenic acid may lead to a specialized form of glossitis and cheilosis, skin, symptoms such as cornification, depigmentation desquamation, etc. Lack of this vitamin also affects the adrenals.
FOLIC ACID (FOLACIN OR PTEROYLGLUTAMIC ACID)
FOLIC ACID (FOLACIN OR PTEROYLGLUTAMIC ACID)
The existence of this nutritional factor was first suggested by Day
It was named folic acid by Chell, Snell. and Williams, because potent concentrates were obtained from spinach leaf (L. folium) The chemical structure was established in 1945.
SOURCES
The richest source of the vitamin is yeast, liver, kidney, and green vegetables, with moderate amounts contained in dairy foods meat, and fish. It is very little in fruits.
FUNCTIONS
(1) The folic acid coenzymes are specifically concerned with biochemical reactions involving the transfer and utilization of the single carbon (C-1) moiety.
(2) The folic acid participates in reactions leading to the synthesis of purines and thymine required for DNA synthesis.
(3) It takes part in the formation and maturation of red blood cells.
DEFICIENCY
Folic acid deficiency is characterized by growth failure, sprue macrocytic anemia of pregnancy, certain macrocytic anemia of children, and leukopenia.
CYANOCOBALAMIN(B12)
(Cobamide Cyanide, Antipernicious Anaemia Factor)
Vitamin B12, the anti-pernicious anemia factor (extrinsic facto of Castle) was first isolated by Smith and Parker in 1948 from the liver as a red crystalline compound containing cobalt and phosphorus.
SOURCES
The only source of cobalamins in nature is via synthesis by microorganisms in the soil, water, and the animal intestine. In contrast to the other vitamins, plants contain no vitamin B12; animal products like milk, liver, kidney, muscle meat, eggs, and cheese are the primary dietary sources of the vitamin.
FUNCTIONS
(1) It is necessary for the maturation of erythrocytes.
It was named folic acid by Chell, Snell. and Williams, because potent concentrates were obtained from spinach leaf (L. folium) The chemical structure was established in 1945.
SOURCES
The richest source of the vitamin is yeast, liver, kidney, and green vegetables, with moderate amounts contained in dairy foods meat, and fish. It is very little in fruits.
FUNCTIONS
(1) The folic acid coenzymes are specifically concerned with biochemical reactions involving the transfer and utilization of the single carbon (C-1) moiety.
(2) The folic acid participates in reactions leading to the synthesis of purines and thymine required for DNA synthesis.
(3) It takes part in the formation and maturation of red blood cells.
DEFICIENCY
Folic acid deficiency is characterized by growth failure, sprue macrocytic anemia of pregnancy, certain macrocytic anemia of children, and leukopenia.
CYANOCOBALAMIN(B12)
(Cobamide Cyanide, Antipernicious Anaemia Factor)
Vitamin B12, the anti-pernicious anemia factor (extrinsic facto of Castle) was first isolated by Smith and Parker in 1948 from the liver as a red crystalline compound containing cobalt and phosphorus.
SOURCES
The only source of cobalamins in nature is via synthesis by microorganisms in the soil, water, and the animal intestine. In contrast to the other vitamins, plants contain no vitamin B12; animal products like milk, liver, kidney, muscle meat, eggs, and cheese are the primary dietary sources of the vitamin.
FUNCTIONS
(1) It is necessary for the maturation of erythrocytes.
(2) As a component of the various coenzymes, vitamin B12 has its greatest effect on nucleic acid formation in the red bone marrow.
(3) It is important for the maintenance of normal health and activity of certain parts of the nervous system.
(3) It is important for the maintenance of normal health and activity of certain parts of the nervous system.
(4) The vitamin B₁2 coenzyme has been shown to catalyze the isomerase reaction in animal tissue.
By this reaction, methylmalonic-CoA is converted to succinyl-CoA. (5) It has a role in the transmethylation process.
ADSORPTION OF VITAMIN B12
Vitamin B12 is absorbed from the ileum, but its absorption is pendent upon the presence of HCl and a constituent of normal gastric juice designated intrinsic factor (IF) by the castle. man intrinsic factor is a mucoprotein that binds one molecule of amine B₁2 per molecule of protein. The gastric parietal cells are a source of both HCl acid and intrinsic factors in man.
DEFICIENCY
The most characteristic sign of a deficiency of vitamin B₁2 in is the development of pernicious or macrocytic anemia. In form of anemia, the blood cells are larger than normal (hence the term 'macrocytic'), but fewer in number. Instead of 5 million cells/cu mm., the count may drop to 1 million/cu. mm. Precious anemia results not from inadequate ingestion of vitamin but from inadequate secretion of "intrinsic factor" in the gastric juice, which promotes the absorption of the ingested vitamin from the intestine. The latter is an essential factor for the creation and maturation of RBCs. Symptoms of perniciousness include numbness and tingling of the hands and feet, a sore and smooth tongue, and poor appetite.
BIOTIN
In 1936, Kogl and Tonnis isolated from egg-yolk a crystalline growth factor for yeast, which they named 'biotin'.
SOURCES
Under ordinary circumstances, sufficient quantities of bio are provided to the mammal by intestinal bacterial synthesis. T vitamin is widely distributed in natural foods. Egg-yolk, kid liver, tomatoes, and yeast are excellent sources. Pea-nuts chocolate contains abundant quantities.
FUNCTIONS
In biological systems, biotin functions as the coenzyme for carboxylases, enzymes that catalyze carbon dioxide "fixation" carboxylation.
DEFICIENCY
Biotin deficiency cannot be produced in most animals merely by diets deficient in this nutrient, presumably because of intestine bacterial synthesis of this compound. However, biotin deficiency has been produced in poultry, monkeys, and rats on synthetic rations. Biotin deficiency follows either sterilization of the intestinal tract, the feeding of raw egg-white, or the administration of biotin antimetabolites. In experiments with rats, dermatitis, retarded growth, loss of hair, and loss of muscular control occur when egg-white was fed as the sole source of protein. Raw egg-w contains glycoprotein avidin which antagonizes biotin and the animal suffers from a deficiency of this vitamin.
INOSITOL
There are 9 isomers of inositol. Myo-inositol is them important one in nature and the only isomer which is biologically effective.
SOURCES
Inositol is found in fruits, meat, milk, nuts, vegetables, grains, and yeast.
FUNCTIONS
The significance of this compound in human nutrition has not been established. Together with choline inositol, has a tropic action in experimental animals.
DEFICIENCY
Deficiency symptoms in mice include so-called spectacled eye, alopecia, and failure of lactation and growth.
CHOLINE
Choline is cannot be classified as the body. the important metabolite, although probably a vitamin since it is synthesized by Acetylcholine, produced from choline and acetic acid, is well known as a chemical mediator of parasympathetic as well as certain other types of activity in the nervous system. Acetylcholine esterase is an enzyme, present in many tissues which hydrolyze acetylcholine to choline and acetic acid.
In many animal species, a deficiency of choline leads to the development of fatty livers causing disturbances in fat metabolism. In the young growing rat, there is also hemorrhagic degeneration of the kidneys.
VITAMIN C
(Ascorbic acid, Antiscorbutic Vitamin)
In 1753, Captain James Lind of the British Navy showed that the disease Scurvy which was common in sailors could be red by giving them Lemons and oranges. In 1907 Holst and Frolich demonstrated that guinea pigs develop scorbutic lesions in a diet of oats and bran. The vitamin was isolated by Szent Gyorgyi (1928) from orange juice. In 1932, King and Waugh isolated the crystalline vitamin, which had previously been termed vitamin C and has been renamed ascorbic acid.
SOURCES
The best food sources of vitamin C are citrus fruits (lime, orange), berries, gooseberries, melons, tomatoes, green peppers, raw cabbage, and leafy green vegetables particularly salad greens, while only a fair source of Vitamin C on a per gram is excellent sources in the average diet. Animal sources are generally or except the adrenal cortex.
The vitamin is easily destroyed by cooking since it is readily oxidized. Mincing of fresh vegetables such as cabbage, the mashing of potatoes, canning, and other food preparation procedures destroy a portion of the ascorbic acid in foods.
FUNCTIONS
(1) Maintains the normal intracellular material dentine and bone; and the integrity of capillary walls.
(2) Has a specific role in collagen synthesis.
By this reaction, methylmalonic-CoA is converted to succinyl-CoA. (5) It has a role in the transmethylation process.
ADSORPTION OF VITAMIN B12
Vitamin B12 is absorbed from the ileum, but its absorption is pendent upon the presence of HCl and a constituent of normal gastric juice designated intrinsic factor (IF) by the castle. man intrinsic factor is a mucoprotein that binds one molecule of amine B₁2 per molecule of protein. The gastric parietal cells are a source of both HCl acid and intrinsic factors in man.
DEFICIENCY
The most characteristic sign of a deficiency of vitamin B₁2 in is the development of pernicious or macrocytic anemia. In form of anemia, the blood cells are larger than normal (hence the term 'macrocytic'), but fewer in number. Instead of 5 million cells/cu mm., the count may drop to 1 million/cu. mm. Precious anemia results not from inadequate ingestion of vitamin but from inadequate secretion of "intrinsic factor" in the gastric juice, which promotes the absorption of the ingested vitamin from the intestine. The latter is an essential factor for the creation and maturation of RBCs. Symptoms of perniciousness include numbness and tingling of the hands and feet, a sore and smooth tongue, and poor appetite.
BIOTIN
In 1936, Kogl and Tonnis isolated from egg-yolk a crystalline growth factor for yeast, which they named 'biotin'.
SOURCES
Under ordinary circumstances, sufficient quantities of bio are provided to the mammal by intestinal bacterial synthesis. T vitamin is widely distributed in natural foods. Egg-yolk, kid liver, tomatoes, and yeast are excellent sources. Pea-nuts chocolate contains abundant quantities.
FUNCTIONS
In biological systems, biotin functions as the coenzyme for carboxylases, enzymes that catalyze carbon dioxide "fixation" carboxylation.
DEFICIENCY
Biotin deficiency cannot be produced in most animals merely by diets deficient in this nutrient, presumably because of intestine bacterial synthesis of this compound. However, biotin deficiency has been produced in poultry, monkeys, and rats on synthetic rations. Biotin deficiency follows either sterilization of the intestinal tract, the feeding of raw egg-white, or the administration of biotin antimetabolites. In experiments with rats, dermatitis, retarded growth, loss of hair, and loss of muscular control occur when egg-white was fed as the sole source of protein. Raw egg-w contains glycoprotein avidin which antagonizes biotin and the animal suffers from a deficiency of this vitamin.
INOSITOL
There are 9 isomers of inositol. Myo-inositol is them important one in nature and the only isomer which is biologically effective.
SOURCES
Inositol is found in fruits, meat, milk, nuts, vegetables, grains, and yeast.
FUNCTIONS
The significance of this compound in human nutrition has not been established. Together with choline inositol, has a tropic action in experimental animals.
DEFICIENCY
Deficiency symptoms in mice include so-called spectacled eye, alopecia, and failure of lactation and growth.
CHOLINE
Choline is cannot be classified as the body. the important metabolite, although probably a vitamin since it is synthesized by Acetylcholine, produced from choline and acetic acid, is well known as a chemical mediator of parasympathetic as well as certain other types of activity in the nervous system. Acetylcholine esterase is an enzyme, present in many tissues which hydrolyze acetylcholine to choline and acetic acid.
In many animal species, a deficiency of choline leads to the development of fatty livers causing disturbances in fat metabolism. In the young growing rat, there is also hemorrhagic degeneration of the kidneys.
VITAMIN C
(Ascorbic acid, Antiscorbutic Vitamin)
In 1753, Captain James Lind of the British Navy showed that the disease Scurvy which was common in sailors could be red by giving them Lemons and oranges. In 1907 Holst and Frolich demonstrated that guinea pigs develop scorbutic lesions in a diet of oats and bran. The vitamin was isolated by Szent Gyorgyi (1928) from orange juice. In 1932, King and Waugh isolated the crystalline vitamin, which had previously been termed vitamin C and has been renamed ascorbic acid.
SOURCES
The best food sources of vitamin C are citrus fruits (lime, orange), berries, gooseberries, melons, tomatoes, green peppers, raw cabbage, and leafy green vegetables particularly salad greens, while only a fair source of Vitamin C on a per gram is excellent sources in the average diet. Animal sources are generally or except the adrenal cortex.
The vitamin is easily destroyed by cooking since it is readily oxidized. Mincing of fresh vegetables such as cabbage, the mashing of potatoes, canning, and other food preparation procedures destroy a portion of the ascorbic acid in foods.
FUNCTIONS
(1) Maintains the normal intracellular material dentine and bone; and the integrity of capillary walls.
(2) Has a specific role in collagen synthesis.
(3) Provides resistance against common colds.
(4) Helps to dissolve cholesterol in the blood.
(5) Plays an important role in wound repair and metabolism.
(6) Protects the body against stress.
DEFICIENCY
Severe vitamin C deficiency produces Scurvy. The pathological signs of this disease are) skin eruptions, swollen bleeding gums, loosening of the teeth, hemorrhages, poorly healing wounds, easy fractures of bones, and increased susceptibility infections. The infant is usually well supplied with vitamin C at birth.
However, infants 6-12 months of age who are fed processed milk formula, not supplemented with fruits and vegetables, are very susceptible to the development of infantile scurvy. Elderly bachelors and widowers who may prepare their own foods are particularly prone to the development of vitamin C deficiency, a syndrome termed as "bachelor scurvy".
(4) Helps to dissolve cholesterol in the blood.
(5) Plays an important role in wound repair and metabolism.
(6) Protects the body against stress.
DEFICIENCY
Severe vitamin C deficiency produces Scurvy. The pathological signs of this disease are) skin eruptions, swollen bleeding gums, loosening of the teeth, hemorrhages, poorly healing wounds, easy fractures of bones, and increased susceptibility infections. The infant is usually well supplied with vitamin C at birth.
However, infants 6-12 months of age who are fed processed milk formula, not supplemented with fruits and vegetables, are very susceptible to the development of infantile scurvy. Elderly bachelors and widowers who may prepare their own foods are particularly prone to the development of vitamin C deficiency, a syndrome termed as "bachelor scurvy".
Reference
Animal physiology by Verma Agarwal/Biochemistry/Vitamins,
Published by Chand publishers
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