VITAMINS Dr Amir Ahmed Introduction The word vitamin

VITAMINS Dr Amir Ahmed

Introduction Ø The word "vitamin" comes from the Latin word vita, means "life". Ø Vitamins are chemicals found in very small amounts in many different foods. Ø “vitamins have been defined as organic compounds which are required in minute amounts to maintain normal health of organisms’. Ø Functions • Regulate metabolism • Help convert energy in fat, carbohydrate, and protein into ATP • Promote growth and reproduction Ø Deficiencies can result in potentially serious consequences

Classification of Vitamins FAT SOLUBLE ØA ØD ØE ØK WATER SOLUBLE Ø B 1 Thiamine Ø Ø Ø Ø B 2 Riboflavin B 3 – Niacin B 5 – pantothenic acid B 6 –Pyridoxine B 8 – biotin B 9 Folic acid B 12 Cyano. Cobalamin C vitamin (ascorbic acid) 3

Vitamin Absorption and Storage • All absorption takes place in the small intestine • Fat-soluble vitamins – Are absorbed in the duodenum – Storage • • Vitamin A is mainly stored in the liver Vitamins K and E are partially stored in the liver Vitamin D is mainly stored in the fat and muscle tissue Can build up in body to point of toxicity

Vitamin Absorption and Storage • Water-soluble vitamins – Absorbed with water and enter directly into the blood stream – Most absorbed in the duodenum and jejunum – Most are not stored in the body – Excess intake excreted through the urine – Important to consume adequate amounts daily – Dietary excesses can be harmful

The Fat-Soluble Vitamins

Vitamin A • Chemical Name • Retinol, Retinal, and Carotenoids including Beta carotene • Solubility in Fat • Function • Vision, Bone growth, Reproduction, Cell functions and in Immune system

Cont. . • Deficiency Disease • Night blindness, hyperkeratosis, and keratomalacia. Conjunctival xerosis, bitot’s spot, Corneal xerosis • Toxicity • Hypervitaminosis A • Food Source • Liver, orange, ripe yellow fruits, leafy vegetables, carrots, pumpkin, squash, spinach, fish, soy milk, milk

Picture of Conjunctival xerosis, bitot’s spot, hyperkeratosis, Corneal xerosis, keratomalacia

Vitamin D Chemical Name Cholecalciferol (D 3), Ergocalciferol (D 2) Solubility in Fat Function Needed for proper absorption of calcium; stored in bones • Deficiency Disease Rickets and osteomalacia • Toxicity Hypervitaminosis D • Food Source Lichen, eggs, liver, certain fish species such as sardines, certain mushroom • • •

Rickets and osteomalacia

Vitamin E • Chemical Name • Tocopherols, Tocotrienols • Solubility in Fat • Function Antioxidant; protects cell walls • Deficiency Disease Deficiency is very rare; mild hemolytic anemia in newborn infants • Toxicity Possible increased incidence of congestive heart failure • Food Source Many fruits and vegetables, nuts and seeds, and seed oils

Vitamin K • Chemical Name • Phylloquinone (k 1), Menaquinones(k 2) • Solubility in Fat • Function Needed for proper blood clotting • Deficiency Disease • Deficiency: increased bleeding and hemorrhage rare, they may occur in some individuals when antibiotic medications kill the intestinal bacteria that produce the vitamin. • Toxicity Decreased anticoagulation effect of warfarin • Food Source Leafy green vegetables such as spinach; egg yolks; liver

To be continued. .