Vitamins lecture 2 Presented By: Ebtesam Al-Sheddi

Fat soluble vitamins Vitamin E The term vitamin E refers to a family of eight related compounds, the tocopherols and the tocotrienols The four major forms of vitamin E are designated , that have varying levels of biological activity Alpha- (or α-) tocopherol is the most active form Termed an antioxidant

Protects cell membranes and other fat-soluble parts of the body (LDL cholesterol) from oxidation May reduce the risk of heart disease May also discourage development of some types of cancer Promotes normal growth and development Promotes normal red blood cell formation Acts as anti-blood clotting agent Plays some role in the body’s ability to process glucose Also been known to aid the process of wound healing Vitamin E

Sources  Plant sources  Cereal grains  wheat germ oil, almonds, sunflower seeds, sunflower oil, safflower oil, hazelnuts, peanut butter, peanuts, corn oil, spinach, broccoli, soybean oil, kiwi and mango. Vegetable and seed oils  Little in animal sources  Beef fed high levels of vitamin E right before slaughter to improve shelf life can be source  The RDA (recommended daily allowance) for vitamin E is 15 mg of d-alpha-tocopherol for adult men and women (1 mg of d-alpha- tocopherol is equal to 1.5 IU, so the RDA is equal to 22.5 IU).

Vitamin E Toxicity Wide range of safe intake compared to other fat soluble vitamins (toxicity rare) –Extreme high doses (50- to 100-fold above recommended intakes) may affect the blood clotting effects of vitamin K and may lead to increased risk of hemorrhage

Fat soluble vitamins Vitamin K Vitamin K2 K 1, phylloquinone Chloroplasts in plants K 2, menaquinone Bacterial synthesis K 3, menadione Synthetic, water soluble form Complexed to improve stability

Physiological Effects of Vitamin K Vitamin K serves as an essential cofactor for a carboxylase that catalyzes carboxylation of glutamic acid residues on vitamin K- dependent proteins. These proteins are involved in: 1) Coagulation 2) Bone Mineralization 3) Cell growth

Coagulation The transformation of liquid blood into a solid gel Stops blood flow in the damaged area Fibrin is the final protein which produces a meshwork to trap RBC and other cells

Vitamin K Dependent Coagulation Certain clotting factors/proteins require calcium to bind for activation Calcium can only bind after gamma carboxylation of specific glutamic acid residues in these proteins The reduced form of vitamin K 2 (vitamin KH 2 ) acts as a cofactor for this carboxylation reaction. These proteins are known as “Vitamin K dependent” proteins

Vitamin K Dependent Proteins factor II (prothrombin) factor VII (proconvertin) factor IX (thromboplastin component) factor X (Stuart factor) protein C & protein S Protein Z

Clotting Cascade

Vitamin K Cycle Glutamic Acid Gamma Carboxy Glutamic Acid Vitamin K Vitamin K Epoxide Vitamin KH2 Vitamin K Dependent Carboxylase Reductase Epoxide Reductase Warfarin Inhibits

The best food sources of vitamin K are green leafy vegetables. Milk and liver. Daily requirement: Dietary Sources Life StageAge Males (mcg/day) Females (mcg/day) Infants0-6 months2.0 Infants 7-12 months2.5 Children 1-3 years30 Children4-8 years 55 Children9-13 years60 Adolescents years75 Adults19 years and older Pregnancy 18 years and younger -75 Pregnancy 19 years and older -90 Breast-feeding 18 years and younger -75 Breast-feeding 19 years and older -90

Vitamin K Deficiency Results in impaired blood clotting and, potentially, bleeding. Vitamin K deficiency can result from: a lack of vitamin k in the diet disorders that reduce fat absorption Taking certain drugs, including anticonvulsants and some antibiotics Use of coumarin anticoagulants Salicylates Large doses of vitamin E Hepatic insufficiency

Symptoms of Vitamin K Deficiency Bruising from bleeding into the skin Nosebleeds Bleeding gums Bleeding in stomach Blood in urine Blood in stool Tarry black stool Extremely heavy menstrual bleeding In infants, may result in intracranial hemorrhage

Vitamin K Deficiency in Infants Newborns are prone to vitamin K deficiency because… 1. Vitamin K and lipids are not easily transported across the placental barrier 2. Prothrombin synthesis in the liver is an immature process in newborns, especially when premature. 3. The neonatal gut is sterile, lacking the bacteria that is necessary in menaquinone synthesis. 4. Breast milk is not a good source of vitamin K Results in a hemorrhagic disease called vitamin K deficiency bleeding (VKDB) This disease is associated with breastfeeding, maladsorption of lipids, or liver disorders.

Vitamin K Deficiency in Adults Uncommon in adults because normal bacteria found in the gut synthesize Vitamin K2 and the vitamin may be consumed from several food sources. Contributing Factors: Biliary obstruction Maladsorption Cystic fibrosis Resection of small intestine Increases risk of bleeding in individuals who suffer from Vitamin K deficiency: Coumarin anticoagulants Certain antibiotics

Vitamin K - Toxicity Not common except with over- supplementation Phylloquinone and menaquinone are relatively nontoxic Jaundice; brain damage Menadione toxic to skin and respiratory tract in high doses

 VITAMIN C L-ascorbic acid, ascorbate Synthesized from glucose by most animals Vitamin C is an electron donor

F UNCTIONS OF V ITAMIN C Enhances absorption of iron reduces iron to more absorbable ferrous form chelates with ferrous ion to make it more soluble

F UNCTIONS OF V ITAMIN C Involved in the biosynthesis of the protein, collagen, found in connective tissues such as cartilage, ligaments, and tendons Involved in the biosynthesis of the protein, collagen, found in connective tissues such as cartilage, ligaments, and tendons

F UNCTIONS OF V ITAMIN C Biosynthesis of the catecholamine norepinephrine Biosynthesis of the catecholamine norepinephrine (neurotransmitter) Bile acid synthesis

 O THER FUNCTIONS Promotes the healing of cuts, abrasions and wounds Promotes the healing of cuts, abrasions and wounds Helps fight infections. Helps fight infections. Inhibits conversion of irritants in tobacco smoke Inhibits conversion of irritants in tobacco smoke and certain foods into cancer-causing substances. and certain foods into cancer-causing substances. Appears to dilate blood vessels and thereby Appears to dilate blood vessels and thereby lessen the risk of developing high blood pressure lessen the risk of developing high blood pressure and heart disease. and heart disease. Helps regulate cholesterol levels. Helps regulate cholesterol levels.

F OOD S OURCES OF V ITAMIN C Citrus fruits Potatoes Green peppers Cauliflower Broccoli Strawberries Romaine lettuce Spinach Easily lost through cooking Sensitive to heat Sensitive air

 D AILY REQUIREMENTS Recommended Dietary Allowance mg per day adult male 90 adult female 75 Children 4-13 years 25 Tolerable Upper Intake Level(adult male) 2,000 mg per day Tolerable Upper Intake Level(adult female) 2,000 mg per day

 D EFICIENCY OF VITAMIN C When there is a shortage of Vitamin C, various problems can arise like : Scurvy disease ;a disease characterized by weakness, fatigue, anemia, swollen joints, bleeding gums and loose teeth and skin discoloration due to "pinpoint" hemorrhages under the skin and a tendency to bruise easily Scurvy disease ;a disease characterized by weakness, fatigue, anemia, swollen joints, bleeding gums and loose teeth and skin discoloration due to "pinpoint" hemorrhages under the skin and a tendency to bruise easily

poor wound healing poor wound healing Edema (water retention) Edema (water retention) weakness, a lack of energy weakness, a lack of energy poor digestion poor digestion painful joints painful joints bronchial infection and colds. bronchial infection and colds.  D EFICIENCY OF VITAMIN C

 T OXICITY Diarrhea Diarrhea nausea nausea skin irritation skin irritation burning upon urination burning upon urination depletion of the mineral copper. depletion of the mineral copper. development of kidney stones due to oxalate formation or hemochromatosis or other diseases related to excessive iron accumulation. development of kidney stones due to oxalate formation or hemochromatosis or other diseases related to excessive iron accumulation.

Thank you!