Fat Soluble Vitamins - Health Benefits PDF

 Definition: Vitamins are organic compounds that characterized by: 1. They are essential for normal health and growth where they are not synthesized in human body. So, they must be supplied in the diet. 2- Their deficiency in the body leading to various diseases. 3. They do not ent...

 Definition: Vitamins are organic compounds that characterized by: 1. They are essential for normal health and growth where they are not synthesized in human body. So, they must be supplied in the diet. 2- Their deficiency in the body leading to various diseases. 3. They do not enter in the structure of the tissues. 4. They are needed in very small amounts.  Classification: Vitamins can be classified according to their solubility into two main categories: A. Fat soluble vitamins: they include A, D, E and K vitamins. Characters: 1. They are soluble in fat solvents. 2. They need bile salts for absorption. 3. They can be stored in the body. B. Water soluble vitamins: they include vitamin C and B complex group. Characters: 1. They are soluble in water 2. Most of them are not stored in the body. Classification: - Vitamins can be classified according to their solubility into two main groups:  Vitamin A (retinol) (Anti-night blindness, Anti-xerophthalmia vitamin) Sources: Plant origin: All pigmented (particularly yellow) vegetables and fruits and the leafy green vegetables. It is present in carrots, tomatoes and potato. Animal origin: It is present in meat, liver, milk, butter , egg yolk and fish liver oils.  I- Role of vitamin A in vision The light receptors of the eye are the rod and cone cells in the retina. Rods are responsible for vision in dim light.Cones are responsible for vision in bright and colored light.  II. Vitamin A act as a hormone 1- Retinoic acid ( vitamin A) is needed for normal growth regulation and for mucin secretion in the mucosa of urogenital tract, respiratory tract, gastrointestinal tract, the cornea and the skin. 2- Retinoic acid is required for the synthesis of the iron-transport protein transferrin. Therefore, vitamin A deficiency leads to anemia. 3- Retinoic acid is responsible for the normal structure and normal function of the adrenal gland. 4- Retinoic acid accelerates the normal growth of bones and teeth. 5- Retinoic acid has a role in reproduction in male and female especially. 6- It is immunostimulant since it controls the differentiation of the various types of the immune cells.  III. Antioxidant activity : vitamin A are antioxidant and may play a role in trapping free radicals in tissues at low partial pressure of oxygen. It complements the antioxidant properties of vitamin E, which is effective at higher oxygen pressure. The antioxidant properties of these two vitamins partially explain their anticancer activity.  Deficiency: 1- In the eye: Night blindness (impaired dark adaptation). cornea becomes dry and rough this occurs lately. Fissuring of cornea. Inflammation of conjunctiva. 2- Growth retardation 3- The skin becomes rough and hyper-keratinized (goose skin, xeroderma). 4- Roughness of mucous membrane of the urinary tract, genital tract, gastrointestinal tract and the respiratory tract leading to repeated infection in these sites.  Vitamin D (calciferol) There are two types of vitamin D : vitamin D2 in plants , and vit-D3 derived from cholesterol.  Sources: I- Provitamins: Present in animals and man only. It is formed in intestinal mucosa from cholesterol then passes to the skin, whereby ultraviolet rays of the sun convert it into active form of vitamin D called cholecalciferol (calcitol ) or (Vitamin D3). II- Vitamin D3 : - The richest source of vitamin D3 is fish liver oils, e.g., cod and shark liver oil. - Egg yolk, liver, butter and milk are poor sources of vitamin D3.  Functions of active vitamin D Vitamin D functions as a hormone more than as a vitamin. The target tissues include the Intestine, bone and kidney. In the intestine induces synthesis of a protein required for calcium absorption (Ca2+-binding protein). It also increases phosphate absorption from intestine. This increases the plasma level of Ca2+ and phosphate.  In the bone, – Vitamin-D3 and parathyroid hormone (PTH) act synergistically to promote mobilization of calcium and phosphate from bone (deminerilization). – Vitamin -D3 increases the synthesis of osteocalcin (Ca2+-binding protein) of bone, thereby influencing the mineralization of bone tissues. In the kidney, Vitamin D3 enhances the reabsorption of Ca2+ and phosphate.  Deficiency It causes rickets in young children and osteomalacia in adults * The causes: - Decrease intake of vitamin D - Minimal exposure to sunlight. - Diseases causing fat malabsorption. - Severe liver and kidney diseases due to failure of active form of vitamin D.  Vitamin E (tocopherols) (anti-sterility vitamin) Sources: Vegetable oils, e.g., wheat germ, cotton seed, olive and coconut oils. Small amounts are present in liver, egg yolk, milk.  Functions: 1-Vitamin E plays an important role as a naturally occurring antioxidant at high oxygen tension, e.g., cellular membranes, RBCs, and lung tissues.Thus, vitamin E is essential for keeping cell membrane integrity. 2-It prevents hemolytic anemia. 3-It has antisterility effect especially in animals.  Deficiency: * The Causes : Lipid malabsorption , e.g., steatorrhoea , unhealthy intestinal mucosa , intake of mineral oil , and general intestinal malabsorption Chronic liver diseases. Decrease intake of the vitamin.  * Manifestations : 1- Anaemia which may be due to decreased production of hemoglobin or hemolysis of RBCs. 2- Sterility in rats. 3- Central nervous system changes. 4- Cancer stomach.  Vitamin K (Anti-haemorrhagic vitamin) Sources: Vitamin K1 is present in spinach, cauliflower and cabbage. Intestinal bacteria synthtize vitamin K  Functions: I- Vitamin K is antihemorrhagic Vitamin K is essential for synthesis and activation of blood clotting factors, e.g., factors V (5), VII (7) ,IX(9) and X(10). Activation of prothrombin (factor-II).  II- Activation of osteocalcin in bones (calcium- binding protein). Vitamin D3 stimulates the synthesis of osteocalcin in an inactive form called pro-osteocalcin. Vit-K converts proosteocalcin into active osteocalcin. So vitamin K deficiency leads to osteomalacia.  Deficiency : The Causes : Deficient intestinal bacteria e.g. long use of antibiotic and in newly born infants. Fat malabsorption syndromes associated with pancreatic dysfunction, biliary disease Long use of dicumarol. This anticoagulant drug antagonizes vitamin K so affect action of coagulation factors. Liver diseases.  Effects: - Hemorrhagic manifestation in skin and mucous membranes due to defect in blood coagulation mechanism. Osteomalacia due to failure of activation of proosteocalcin into active osteocalcin