1. بسم الله الرحمن الرحيم
Vitamins
Bioc. 201

2. Vitamins Organic compounds. Required in small quantities.
Needed for a variety of biochemical functions.
They do not enter in tissue structure.
Cannot be synthesized by the body, must be supplied by the diet.
They are not a source of calories (energy).
Their deficiency in diet results in characteristic disease, Example: Scurvy from vitamin C deficiency , Rickets from vitamin D deficiency.
Nutritional Value lost by: bacteria, light, oxidation and heat.
Vitamins intake depends on: Age, Gender, Pregnancy, and Lactation.

3. Biochemical Functions
Some of vitamins have hormone-like functions as regulators of mineral metabolism (e.g. vitamin D) or regulators of cell and tissue growth and differentiation (e.g. some forms of vitamin A).
Others function as antioxidants, (e.g. vitamin E and sometimes vitamin C).
The largest number of vitamins (e.g. vitamins B complex) function as precursors for enzyme cofactors, that help enzymes in their work as catalysts in metabolism.

4. Vitamin Requirements
Recommended Dietary Allowances (RDA) is a norm for how much of various nutrients people should take in every day to stay healthy.

5. Classification of vitamins
Water soluble vitamins:
Dissolve easily in water and, in general, are readily excreted from the body. Because they are not readily stored, consistent daily intake is important. Many types of water-soluble vitamins are synthesized by bacteria.
Ascorbic acid (vitaminC)
Vitamin B1 (thiamine)
Vitamin B2 (riboflavin)
Vitamin B3 (niacin or niacinamide)
Vitamin B5 (pantothenic acid)
Vitamin B6 (pyridoxine, pyridoxal, or pyridoxamine, or pyridoxine hydrochloride)
Vitamin B7 (biotin)
Vitamin B9 (folic acid)
Vitamin B12 (various cobalamins; commonly cyanocobalamin in vitamin supplements)
Fat soluble vitamins:
Stored in the liver and adipose tissue. These are not readily excreted from the body. In fact, consumption of vitamin A and D in excess of the recommended dietary allowances can lead to accumulation of toxic quantities of these compounds.
Vitamin A
Vitamin D
Vitamin K
Vitamin E

6. Classification of vitamins

7. Water Soluble vitamins: Vitamin B
are important for healthy skin and nervous system.
Ascorbic acid (vitaminC)
Vitamin B1 (thiamine)
Vitamin B2 (riboflavin)
Vitamin B3 (niacin or niacinamide)
Vitamin B5 (pantothenic acid)
Vitamin B6 (pyridoxine, pyridoxal, or pyridoxamine, or pyridoxine hydrochloride)
Vitamin B7 (biotin)
Vitamin B9 (folic acid)
Vitamin B12.

8. Vitamin B1 (Thiamine)
The biological active form of the vitamin is Thiamine pyrophosphate (TPP). It is formed by transfer of a pyrophosphate group from ATP to thiamine.
Functions:
Thiamine pyrophosphate serves as a coenzyme.
Essential for release of energy from food.
Necessary for appetite and good health.
Needed for normal functioning of nervous system.
Sources: Meat and liver, whole-grain, spinach.
Deficiency:
Beri-beri disease: is a neurological disease characterized by:
Dry skin.
Irritability.
Disorderly thinking.
Progressive paralysis.
Recommended Daily Allowance (RDA): 1mg per day.
Requirement increases with energy expenditure.

9. Vitamin B2 (Riboflavin)
The two biologically active forms are:
flavin mononucleotide (FMN)
flavin adenine dinucleotide (FAD)
Formed by the transfer of an AMP moiety from ATP to FMN.
Functions:
Metabolism of carbohydrates, proteins and fats (coenzyme FMN, FAD).
Growth, repair, development of body tissues - healthy skin, eyes and tongue
The principal growth promoting factor in the vitamin B complex.
Sources: liver, milk, cheese, leafy vegetables.
Deficiency
Pellagra characterized by:
loss of appetite
Cracks at corners of mouth
Dermatitis around nose and lips.
Tongue appearing smooth and purplish
Eyes sensitive to light.
Mental disorder
Diarrhea , possible death.
RDA: mg per day.

10. Vitamin B3 - Niacin (Nicotinic acid)
Nicotinamide, a derivative of nicotinic acid that contains an amide instead of a carboxyl group, also occurs in the diet.
Functions:
Energy production from foods;
aids digestion,
promotes normal appetite;
promotes healthy skin, nerves.
Niacin is a precursor to NAD+/NADH and NADP+/NADPH, which play essential metabolic roles in living cells.
Niacin is involved in both DNA repair, and the production of steroid hormones in the adrenal gland.
Sources: liver meat, yeast extracts, milk and cheese, vegetables, grains.
Deficiency:
pellagra, a disease involving the skin, gastrointestinal (GI) tract, and CNS.
The symptoms of pellagra progress through the three Ds: dermatitis, diarrhea, dementia, and, if untreated, death.
RDA: Recommended Daily Allowance mg per day.

11. Vitamin B5 (Pantothenic acid)
Pantothenic derives from Greek word meaning from every where
Functions:
Synthesize coenzyme-A (CoA).
Synthesize and metabolize proteins, carbohydrates, and fats.
Sources: Liver, kidney, meats, egg yolk, whole grains, legumes; also made by intestinal bacteria.
Deficiency:
Unknown. only occurs only in cases of the most severe life - threatening malnutrition. Most individuals likely obtain sufficient amounts from dietary sources.
NO RDA has been established.

12. Vitamin B6 (pyridoxine)
Vitamin B6 is a collective term for
pyridoxine
pyrodoxal
pyrodoamine (all derivatives of pyridine).
They differ only in the nature of the functional group attached to the ring.
pyridoxine occurs primarily in plants, whereas pyrodoxal and pyrodoxamine are found in foods obtained from animals.
All three compounds can serve as precursors of the biologically active coenzyme, piyrodoxal phosphate.

13. Vitamin B6 (pyridoxine)
Functions:
The metabolically active form of vitamin B6,
is involved in many metabolic process such as amino acid, glucose and lipid metabolism, neurotransmitter synthesis, histamine synthesis, hemoglobin synthesis and function, and gene expression.
Pyridoxal phosphate generally serves as a coenzyme for many reactions and can help facilitate decarboxylation, transamination, racemization, elimination, replacement.
Source: Meats, whole grains and cereals, legumes, green, leafy vegetables.
dietary deficiencies in pyridoxine are rare but have been observed in:
newborn, infants fed formulas low in vitamin B6.
women taking oral contraceptive.
alcoholics.
RDA: 2mg per day.
Toxicity: Neurologic symptoms have been observed at intakes of greater than 2g/d.

14. Vitamin B7 (Biotin, also Known Vitamin H
Biotin is a coenzyme in carboxylation reactions, in which it serves as a carrier of activated carbon dioxide.
Functions:
A coenzyme important in lipid and carbohydrates metabolism.
It also contributes towards healthy nails, skin and hair. It is therefore found in many cosmetic and health products for the skin and hair.
Sources: liver, kidney, egg yolk, milk, most fresh vegetables, also made by intestinal bacteria.
Deficiency:
Uncommon under normal circumstances; Hair loss (alopecia), red rash around the eyes, nose, mouth, and genital area, fatigue; loss of appetite, nausea, vomiting; depression; muscle pains; anemia.

15. Vitamin B9 (Folic Acid) Functions:
Folic acid (or folate), which play a key role in one-carbon metabolisms, is essential for the biosynthesis of several compounds.
Important to take folic acid prior to pregnancy and vital during first 3 months pregnancy to prevent NTD (Neural tube defects are severe abnormalities of the central nervous system that develop in babies during the first few weeks of pregnancy resulting in malformations of the spine and brain.
Tetrahydrofolate receives one-carbon fragments from donors such as serine, glycine, and histidine and transfers them to intermediates in the synthesis of amino acids, purines, and thymine, a pyrimidine found in DNA.
Red blood cell formation
Essential for synthesis of DNA and RNA (coenzyme)
Development of brain, spinal cord and skeleton in foetus.
Enhances brain health. Folic acid supplementation may improve memory.
Sources: liver, fortified cereals, green leafy vegetables, potatoes, milk
Deficiency:
Megaloblastic anaemia results from inhibition of DNA synthesis during red blood cell production ,causes diminished synthesis of purines and thymidine, which leads to an inability of cells to make DNA and, therefore, they cannot divide.
Neural tube defect
Fatigue in mild cases
RDA: 300 µg per day (more during pregnancy).

16. Vitamin B12 (CyanoCobalamin)
Vitamin B 12 is synthesized only by microorganisms; it is not present in plants.
Animal obtain the vitamin preformed from their natural bacterial flora or by eating foods derived from other animals.
Functions:
support production of red blood cells and prevent anemia
helps make DNA, the genetic material in all cells.
allow nerve cells to develop properly
help your cells metabolize protein, carbohydrate, and fat and energy production.
Sources: Meats, liver, kidney, fish, oysters, shellfish, eggs, milk and milk products.
Deficiency:
Vitamin B12 deficiency is rarely a result of an absence of vitamin in the diet.
It is much more common to find deficiencies in patients who fail to absorb the vitamin from the intestine, resulting in pernicious anemia.
Neurological disorders; degeneration of peripheral nerves that may cause numbness, tingling in fingers and toes.
RDA: 3-4 µg per day.

17. Vitamin C (Ascorbic Acid)
The active form of vitamin C is ascorbate cid.
Functions:
Formation of collagen, helps form connective tissue that hold bones, muscles, and tissues together, wound healing; maintaining blood vessels facilitates the absorption of iron, calcium, production of brain hormones, immune factors , Protects the body from free radicals (antioxidant), reduce the risk of heart attack and slow down the progression of atherosclerosis, because it is protect arteries against damage.
Sources: Citrus fruits, broccoli, strawberries, melon, green pepper, tomatoes, dark green vegetables, potatoes.
Deficiency:
Weight loss , fatigue and joint pain and reduced resistance to colds and infections
Scurvy, a disease characterized by sore, spongy gums loose teeth fragile blood vessels swollen joints anemia.
RDA: 30-60mg per day.
Consumption of diets rich in these compounds is associated with a decreased incidence of some chronic diseases, such as coronary heart disease and certain cancer.

18. Fat Soluble Vitamins
Vitamin A
Vitamin D
Vitamin K
Vitamin E

19. Vitamin A (Retinol and Beta-Carotene)
Family of molecules found in the body in 3 forms: Retinol, Retinal, Retinoic acid collectively known as retinoids.
Retinol:
A primary alcohol containing a β-ionone ring with an unsaturated side chain. Named because of its concern with retina of eye and only found in animal foods.
Beta-Carotene:
plant foods contain β-carotene, which can be oxdatively cleaved in the intestine to yield two molecules of retinal.

20. Vitamin A (Retinol and Beta-Carotene)
Functions:
Helps to form skin and mucous membranes and keep them healthy, thus increasing resistance to infections; essential for night vision; promotes bones and tooth development.
Beta carotene is an antioxidant and may protect against cancer.
Sources:
Retinol: liver oil, Liver, dairy products, egg yolk.
Beta-Carotene: dark green leafy, vegetables, broccoli, carrots, deep orange, fruits and vegetables.
Deficiency:
Mild: Night blindness, diarrhea, intestinal infections, impaired vision.
Severe: leads to dryness of the conjunctiva, cornea and inflammation of eyes, If untreated result blindness, Keratinization of skin and eyes.
Over 500,000 children worldwide are blinded each year caused by insufficient vitamin A in the diet
RDA: 600 µg per day.
90% of Vitamin A in the body is stored in the liver.

21. Vitamin D (Cholecalciferol and Ergoclciferol)
The D vitamins are a group of sterols that have a hormone-like function. The active molecule, 1,25 (OH)2 D3 ( 1,25-dihydroxycholecalcifero).
Functions:
The most prominent actions of 1,25-(OH)2 D3 are to regulate the plasma levels of calcium and phosphorus.
Increasing uptake of calcium by the intestine
Minimizing loss of calcium by the kidney
Stimulating resorption of bone
Sources: sunlight conversion, vitamin D-fortified dairy products, fish, liver oils, dairy products, oily fish, margarine.

22. Vitamin D (Cholecalciferol and Ergoclciferol)
Ergocalciferol
Cholecalciferol
Formed by action of ultra violet light on fungi and yeasts.
Manufactured synthetically for use as vitamin supplement
The sunshine Vitamin!
The sun activates Provitamin 7 dehydro cholesterol present in fat under skin
Provitamin 7 dehydro cholesterol
Cholecalciferol

23. Vitamin D (Cholecalciferol and Ergoclciferol)
Deficiency:
demineralization of bone, resulting in rickets in children osteomalacia in adults.
RDA: 200IU of vitamin D.
Toxicity:
Vitamin D is the most toxic of all vitamins.
Like all fat-soluble vitamins, vitamin D can be stored in the body and is only slowly metabolized.
High doses (100,000 IU for weeks or months) can cause loss of appetite, nausea, thirst, and stupor.
Enhanced calcium absorption and bone resorption results in hypercalcemia, which can lead to deposition of calcium in many organs, particularly the arteries and kidneys.

24. Vitamin E -Tocopherols
The vitamin E consist of eight naturally occurring tocopherols, of which α-tocopherol is the most active.
Functions:
Powerful antioxidant in prevention of nonenzymic oxidation of cell components (for example, polyunsaturated fatty acids) by molecular oxygen and free radicals.
Improves absorption of vitamin A.
prevents damage to cell membranes.
Sources: vegetable oils, margarine, butter, liver, eggs, whole grain products, leafy greens.
Deficiency:
sensitivity of erythrocytes to peroxide, and the appearance of abnormal cellular membranes.
RDA: 10 mg for men and 8 mg for women.
Vitamin E requirement increases as the intake of polyunsaturated fatty acid increases.
Toxicity: the least toxic of the fat-soluble vitamins no toxicity has been observed at dose of 300 mg/day.

25. Vitamin K
Vitamin K exists in several forms, for example in plants as phylloquinone (vitamin K1) , in intestinal bacterial flora as menaquinone (vitamin K2). Menadione as synthetic derivative of vitamin K, is available for therapy purpose.
Functions:
Constituent of prothrombin which is necessary in blood clotting.
Sources: cabbage, cauliflower, spinach, egg yolk and liver, synthesis by the bacteria in the gut.
RDA: There is no RDA for vitamin K, but 70 to 140 mg/day is recommended as an adequate level.
Toxicity: Prolonged administration of large doses of vitamin K can produce
Hemolytic anemia
Jaundice in the infant
due to toxic effects on the membrane of red blood cells.

26. How vitamins help each other
Vitamin E keeps Vitamin A from being destroyed in the intestines.
Vitamin D enables the body to absorb calcium and phosphorous.
Vitamin C helps folate build proteins.
Vitamin B1 works in digestive system with niacin, pantothenic acid acid and magnesium