Vitamins Lecture Notes PDF

Title of the lecture: Vitamins STRUCTURE, FUNCTION, CLASSIFICATION & CLINICAL IMPORTANCE By: Professor Dr. Salar A. Ahmed MSc. Ph.D. Aristotle University of Thessaloniki - Greece Univer...

Title of the lecture: Vitamins STRUCTURE, FUNCTION, CLASSIFICATION & CLINICAL IMPORTANCE By: Professor Dr. Salar A. Ahmed MSc. Ph.D. Aristotle University of Thessaloniki - Greece University of Kurdistan Hawler School of Medicine Email: [email protected] Introduction: Vitamins Are organic components in food that are needed in very small amounts for growth, maintaining good health & and are necessary for many life functions. Everybody must eat a certain amount of vitamins to stay healthy. Are chemicals found in very small amounts in many different foods.  General characteristics of vitamins Are natural components of foods Are essential for normal physiologic function When absent from the diet, they will cause a specific deficiency. Vitamins are required in small quantities in the diet because they cannot be synthesized by the body. Water soluble vitamins cannot be stored in human tissues. Their excess is excreted with urine. ✓ Significant amounts of fat soluble vitamins can be stored in adipose tissue and the liver. ✓ Synthetic vitamins are identical to natural vitamins. ✓ Once growth and development are completed, vitamins remain essential nutrients for the healthy maintenance of the cells, tissues, and organs.  Differences between vitamins and other organic foodstuffs l-Vitamins do not enter into tissue structures. 2-Vitamins do not undergo degradation for providing energy. 3-Water soluble vitamins ,play an important role as co-enzymes. 4-Most of them can not be synthesized in the human body, so they must be supplied in the diet.  functions of vitamins Vitamins are helpful for health and life in the following respects: (a) They build up the resistance of the body against diseases. (b) Prevent and cure various diseases (c) Help the digestion and utilization of mineral, salts and Carbs., lipids, proteins. (d) They also convert food into energy, and repair cellular damage (e) Help health protection. (f) Help the maintenance of proper health and normal growth.  Classification How are they classified? On the basis of their solubility vitamins are mainly 2 types- Fat soluble vitamins Water soluble vitamins  Fat soluble vitamins: ❖ Vitamins that dissolve in fat. ❖ Because fat is easily stored on our body, fat-soluble vitamins can be stored in the body's fatty tissue. This means they can accumulate and be saved for later use. ❖ Are absorbed along with fats ❖ The fat-soluble vitamins are A, D, E and K.  water soluble vitamins include the vitamin C and B-complex vitamins Vitamins that dissolve in water. Because our body is a watery environment, these vitamins can move through our body pretty easily, and they can also be flushed out by the kidneys. Water-soluble vitamins There are eight B-complex vitamins, including (B1, B2, B3, B5, B6, B7, B9 and B12)..  Vitamin A is a group of unsaturated nutritional organic compounds, that includes retinol, retinal, retinoic acid, and several pro- vitamin a carotenoids, among which beta-carotene is the most important. Its active form is present only in Animal Tissue. Found in animal and plant sources How much is enough (Daily requirement)? Men and women – 600 g. Pregnancy and lactation – 900 g. Infants – 300 g. Children – 600 g Where does it come from? Vit. A plays a role in a variety of functions throughout the body, such as: Vision Gene transcription, Cell division and differentiation Regulate Immune System Embryonic development and reproduction Bone metabolism Hematopoiesis (the production of blood cells and platelets) Skin and cellular health Antioxidant activity  Vitamin D Vitamin D refers to a group of fat-soluble secosteroids (a type of steroid with a "broken" ring) found in liver and fish oils, or obtained by irradiating provitamin D with UV light and are responsible for enhancing intestinal absorption of calcium, iron, magnesium, phosphate and zinc. It is also called Sunshine Vitamin Sunshine Vitamin: it is available in 2 forms. Cholecalciferol (Vit. D3) : is made from 7 dehy-drocholesterol in the skin of animals and humans. Calciferol (Vit.D2): is obtained artificially by irradiation. Dietary source of vitamin D  How Much Vitamin D Should You Take For Optimal Health? Daily requirement Recommended Dietary Allowances (RDA ) Varies according to age ,sex and individual conditions and normally it is about : 2.5 Mg. in adult and 10 Mg. in infant ,children ,pregnant  What does vitamin D do? Functions of Vit. D Calcium Balance Cell Differentiation Immunity Blood Pressure Regulation Development of Bones & Teeth How does Vit. D affect muscles? Vit. D plays a crucial role in maintaining muscle health, & a deficiency can lead to various musculoskeletal problems, including muscle weakness & atrophy. Here's how vit. D is related to muscle function: Ca Regulation: Vit.D is essential for the regulation of Ca & P in the body. Ca is critical for muscle contraction, & a lack of Vit.D can lead to impaired Ca absorption, affecting muscle function. Muscle Protein Synthesis: Vit.D is involved in the synthesis of muscle proteins. A deficiency can hinder the process of building & repairing muscle tissue.  Inflammation & Immune Function: Vit. D has anti-inflammatory effects & plays a role in immune system function. Inflammation can contribute to muscle weakness & wasting. Nerve-Muscle Interaction: Vit. D is involved in the communication between nerves & muscles. A deficiency may disrupt this communication, leading to muscle weakness. Balance & Coordination: Vit. D is important for maintaining balance & coordination, which are essential for preventing falls & injuries, especially in older adults.  Vitamin E? α tocopherol It is a yellow oily liquid freely soluble in fat solvent. They are naturally occurring anti-oxidant. – Reduce the energy of the free radical – Stop the free radical from forming in the first place – Interrupt an oxidizing chain reaction to minimize the damage of free radicals It is also called the anti-aging factor.  Where does it come from Specific Food Sources Vegetable oils – Corn, cottonseed, and peanut oil nuts and seeds – Almonds, sunflower seeds, walnuts, Vegetables and fruits – Spinach, lettuce, onions, blackberries, apples Recommended Dietary Intake Men - 8 – 10mg Women – 5- 8mg  Functions of vitamin E ▪ Powerful Antioxidant ▪ Protects cell membranes and other fat-soluble parts of the body (LDL) from oxidation ▪ May reduce the risk of heart disease ▪ May also discourage the development of some types of cancer. Free radical scavenger Protection of double bonds in polyunsaturated fatty acids and oxidation of polyunsaturated fatty acids Works in conjunction with selenium Vitamin E also plays a role in neurological functions and inhibition of platelet aggregation Skin protection Anti-inflammatory Hormonal regulation Promotes normal red blood cell formation Acts as an anti-blood clotting agent  How does Vit.E Prevent aging? Vit. E affects wrinkles by: Boosting connective tissue or collagen production, Supporting new skin cell growth & speeding up cell regeneration.  What is vitamin K ? anti – hemorrhagic vitamin. Vitamin K refers to a group of structurally similar, fat-soluble vitamins the human body needs for complete synthesis of certain proteins that are required for blood coagulation, and also certain proteins that the body uses to binding of calcium in bone and other tissues. Vitamin K is naturally produced by bacteria in the intestines.  It is essential for the production of a type of protein called prothrombin & other factor involved in the blood clotting mechanism. Hence it is known as antihemorrhagic vitamin. Types of vitamin K Vitamin K1 Vitamin K2 Dietary requirement Men and women – 70 –140 g. Children – 35 – 75 g  Dietary sources of vitamin K The source of vitamin K are animal products ( egg, milk , red meat , dark green vegetables like spinach)  Functions of Vitamin K It is essential for the hepatic synthesis of coagulation factors Clotting – it prevents hemorrhage , essential to stop bleeding from wounds Oxidative phosphorylation: it acts as a co-factor in oxi-red associated with lipid People with vit. K deficiency may experience easy bruising (injure) and nosebleeds, etc WATER SOLUBLE VITAMINS Water-soluble vitamins are found in vegetables, fish, and meat. These are essential coenzymes required in energy releasing mechanisms. They also act as coenzymes for the metabolism of proteins, carbohydrates and fats. Here's how Vit. K deficiency can contribute to these symptoms: Clotting Factor Synthesis: It is necessary for the synthesis of clotting factors Impaired Coagulation: In the absence of adequate clotting factors, the blood takes longer to form clots in response to injury. This delayed coagulation increases the risk of bleeding from even minor injuries, resulting in easy bruising. Weak Blood Vessel Walls: Vit. K also plays a role in activating proteins that help maintain the integrity of blood vessel walls. In the absence of sufficient Vit. K, blood vessels may become more fragile, making individuals more prone to nosebleeds. Bone health Vit. K provides an essential role in promoting bone health. It impacts bones in various ways. For instance, ✓ It is a key coenzyme for the gamma-glutamyl carboxylase, which converts glutamic acid residues in Vit. K-dependent proteins to γ- carboxyglutamic acid, (It acts as Ca binding groups). Osteoblasts produce at least 3 different Glu-containing proteins: osteocalcin, matrix Glu-protein, & protein S. After cellular secretion of these proteins, the main part of each remains bound to the inorganic matrix in bone Regulating genetic transcription of osteoblastic markers, & Regulating bone reabsorption. Act as calcium binding groups in these proteins They include- ❖ Vitamin C (ascorbic acid) B- Complex ❖ B1- Thiamine ❖ B2- Riboflavin ❖ B3 – Niacin ❖ B5 – Pantothenic acid ❖ B6 – Pyridoxine ❖ B7 – Biotin ❖ B 9- Folic acid ❖ B12 -Cobalamin  What is vitamin C (ASCORBIC ACID)? It is also called ascorbic acid and antibiotic vitamin. water-soluble It is the most active reducing agent. It is a powerful antioxidant Synthesized by most animals (not by a human) DIETARY SOURCES OF VITAMIN C Citrate fruits Daily intake Men – women – 70-90mg Children –40mg Infant – 25mg Pregnancy & lactation – 80mg  Vitamin C’s functions Synthesis of collagen. Maintenance – necessary for the maintenance of bones & proper functioning of the adrenal & thyroid gland. Antioxidant It stimulates immune function, combats (fighting) bacterial infection, reduces the effects of allergy-producing substances and protects vitamins, A, E and some B complex vitamins from oxidation.  What is the role of Vit. C in collagen synthesis Synthesis of collagen. Vit. C is absolutely essential for the synthesis of collagen. Vit. C is the essential cofactor for the two enzymes required for collagen synthesis: Proline hydroxylase (to stabilize the collagen molecule) & Lysine hydroxylase (to give structural strength cross-linking). Proline hydroxylase: It catalyzes the hydroxylation of proline on collagen Ascorbic acid and ferrous iron (II) are cofactors Ascorbic acid is essential to keep the iron in its ferrous (F+2) form & it is essential for the maturation & cross-linking of collagen. Lysine hydroxylase: It catalyzes the hydroxylation of lysine residues present in collagen Vit.C & ferrous iron are cofactors Vit.C is essential to keep the iron in the ferrous form & It is essential for the maturation & cross-linking of collagen (strong chemical bonds with adjacent fibrils) It helps provide stability to the triple-helical structure of collagen by forming hydrogen bonds. They play a crucial role in stabilizing intra- & intermolecular cross-links.  What is the role of Vit.C in bone formation Bone formation Vit.C is required for bone formation too Does vitamin C promote bone healing? Vit C is a key element in the healing of fractures. It functions in the hydroxylation of two amino acids (proline & lysine) needed to form the triple helix of collagen, which is essential for bone healing.  Vitamin C deficiency Disease results from severe Vit.C deficiency Scurvy Leads to the formation of brown spots on the skin, Bleeding gums, Small red skin discolorations caused by ruptured small blood vessels Sublingual hemorrhages, Easy bruising, Impaired wound & fracture healing, Joint pain Loose & decaying teeth Hemorrhagic tendency In Vit.C deficiency, collagen is abnormal & the intracellular cement substance is brittle, so capillaries are fragile, leading to the tendency to bleed even under minor pressure Toxicity is rare. The most common side effect with ingestion of large amounts (2 g/day) of the vit.C is Gastrointestinal problems which characterized by abdominal pain & osmotic diarrhea. Other side effects include an increased risk of kidney stones & iron toxicity for those with renal disease & disorders of iron metabolism.  Vitamin B1 (Thiamine) (Anti-beriberi) It is a colorless basic organic compound composed of a sulfated ring. All living organisms use thiamine, but it is synthesized only in bacteria, fungi, and plants. Contains sulfur and nitrogen group Destroyed by alkaline and heat Coenzyme: Thiamin pyrophosphate(TPP) DIETARY SOURCES OF VITAMIN B1 Tuna, sunflower, white beans, black beans, green beans Daily intake Men – 1.3 mg women – 1.0 mg Pregnancy and lactation – 2 mg. Children – 1.1mg.  Functions Vitamin B1 is very essential for energy production. The most important use of thiamine is in the treatment of beriberi, a condition caused by a deficiency of thiamine in the diet. Symptoms include swelling, tingling or burning sensation in the hands and feet, confusion, difficulty breathing. It helps in maintaining a healthy nervous system. is necessary for healthy mucous membranes. It helps in the digestion of food. It provides strength to muscles. It is very useful for the proper functioning of hearing Beriberi is a disease caused by a B1 deficiency,. There are two types of disease: Wet & dry beriberi. Wet beriberi affects the heart and circulatory system. In extreme cases, wet beriberi can cause heart failure. Dry beriberi damages the nerves and can lead to decreased muscle strength and eventually, muscle paralysis. Beriberi can be life- threatening if it isn’t treated. Symptoms include swelling, tingling or burning sensation in the hands and feet, confusion, & difficulty breathing.  Vitamin B2 (RIBOFLAVIN) It is also called the beauty vitamin. it is a water-soluble, yellowish-green compound The word riboflavin is derived from 2 sources Ribose sugar and flavin It is widely involved in the oxidation-reduction reaction. DIETARY SOURCES OF VITAMIN B2 Yogurt, Soybeans Mushrooms, Spinach Goat milk Daily intake Men – 1.5mg women – 1.2 mg Pregnancy and lactation – 2 to 2.3 mg. Children – 1.3mg.  FUNCTIONS AND HEALTH BENEFITS OF RIBOFLAVIN It is essential for normal growth. It is involved in the metabolism of carbohydrates, fat & proteins. it helps in digestion it helps in the proper functioning of the Nervous system It is very useful for normal tissue respiration. Necessary for healthy mucous membranes Good for skin, nails, and eyes, It helps in protects the body against cancer It prevents headache, anemia,  Vitamin B3 (Niacin) It is also known as niacin or nicotinic acid. it is essential for metabolism. It is a colorless, water-soluble solid derivative of pyridine, It is a precursor of the coenzyme NAD (Nicotinamide adenine dinucleotide). DIETARY SOURCES OF VITAMIN B2 Daily intake Men – 17mg women – 13 mg Pregnancy and lactation – 12 to15 mg. Children – 15mg.  Functions of Niacine (Vit B3) It helps in releasing energy from carbs, fats, and proteins. is very essential for DNA synthesis. it is essential for the production of sex hormones It is also helpful in reducing headache. Vitamin B3, like niacinamide, may improve arthritis symptoms, including increasing joint mobility and reducing the amount of anti- inflammatory medications needed. It is necessary for healthy skin, nerves and digestive system. High doses of niacin medications are used to prevent the development of atherosclerosis and to reduce recurrent complications such as heart attack and vascular disease in those with the condition. It helps to detoxify the body. It is very essential for the proper digestion of the food Here are some ways in which niacin may contribute to muscle health: Energy Metabolism: Niacin is a key component of coenzymes NAD and NADP. These coenzymes play a fundamental role in the conversion of food into energy. Adequate energy production is essential for muscle contraction & overall muscle function. Blood Flow and Oxygen Delivery: Niacin has vasodilatory effects, meaning it can help dilate blood vessels. Improved blood flow can enhance the delivery of oxygen and nutrients to muscles during exercise. This increased oxygen supply is crucial for optimal muscle performance and recovery.  Anti-Inflammatory Effects: By reducing inflammation, niacin may indirectly support muscle health. Muscle Repair and Growth: Niacin is involved in DNA repair and cell signaling processes. These functions are important for the repair and growth of muscle tissue, especially during periods of exercise-induced stress. Hormone Regulation: Niacin is involved in the regulation of certain hormones, including insulin. Proper insulin function is essential for nutrient uptake by muscles and the maintenance of blood sugar levels. Stable blood sugar levels are important for sustained energy during exercise.  Vitamin B5 (Pantothenic acid) It is also known as Pantothenic Acid, This word derived from the Greek word pantos meaning everywhere. Part of Coenzyme-A Essential for metabolism of carbs, fat, protein Daily requirement Men – 10 mg women – 10 mg Children – 5.5mg.  Functions of vitamin B5 Plays an important role in helping release energy from sugars, and fats. It is important for releasing the energy stored as fat, it is equally important for the creation of fat. Two basic types of fats - fatty acids and cholesterol - both require the CoA form of B5 for their synthesis. They are essential for cell metabolism. Accelerates wound healing. It is also used as an anti-stress factor. Allergies, headaches, arthritis, psoriasis, insomnia, asthma, and infections have all been treated with some effectiveness using vitamin B5.  Vit B6 (Pyridoxine B6) Vitamin B6 refers to a group of chemically very similar compounds which can be interconverted in biological systems. It is part of the vitamin B complex group, and its active form, Pyridoxal 5'- phosphate (PLP) serves as a cofactor in many enzyme reactions in amino acid, glucose, and lipid metabolism. It is a white crystalline substance soluble in water and alcohol. Daily requirement Men – women – 2 mg Children – 1.7 mg. Infant – 0.1-0.4 mg DIETARY SOURCE OF VIT B6 Milk Fish Vegetables Beans Eggs Peanuts, sunflower seeds, etc.  Functions of vitamin B6 Make antibodies: are needed to fight many diseases. Maintain normal nerve function Make hemoglobin. A vitamin B6 deficiency can cause a form of anemia. Break down proteins. The more protein you eat, the more vitamin B6 you need. Keep blood glucose in normal ranges Assists in the balancing of (K) and (Na) levels. Promotes RBC production. Production of certain hormones like (Serotonin, Dopamine, Noradrenaline and Adrenaline)  Vitamin B7 (BIOTIN) Vitamin B7 or Biotin, also known as vitamin H or coenzyme R. Biotin is a coenzyme for carboxylase enzymes, involved in the synthesis of fatty acids and in gluconeogenesis DIETARY SOURCES OF VIT B7 Daily requirement Men – women – 100- 200 g Children – 50-200 g. Infant – 35 g  FUNCTIONS OF VITAMIN B7 Normal macronutrient metabolism; Normal energy-yielding metabolism; The maintenance of normal skin and mucous membranes; The normal function of the nervous system; The maintenance of normal hair; Normal psychological functions. Vitamin B9 It is also known as folic acid or folate. It is a yellow crystalline substance. DIETARY SOURCE RDA= 400 micrograms  Functions of vitamin B9 Formation of RBC – folic acid in combination with vitamin B12 is essential for the formation, maturation. it is necessary for the growth & division of all body cells, it is essential for the health of skin & hair it is an important nutrient for the pregnant women & her developing fetus.& folic acid improves lactation. DNA synthesis Transfer of single carbon units Synthesis of adenine and guanine Anticancer drug Vitamin B12 (COBALAMIN) Is a deep red crystalline compound called cobalamin Sources Vitamin B12 is mostly found in animal products such as meat, milk, cheese, and eggs. The recommended dietary allowances is : 1.8 g.  Functions of vitamin B12 It is essential for the production of RBCs It helps keep the body’s nerve and blood cells healthy and It helps make DNA, It also helps prevent a type of anemia called megaloblastic anemia It is important for metabolism It promotes growth and increases appetite.