FATS AND LIPIDS..........................

1. FATS/LIPIDS VITAMINS

2. OUTLINE Definition of fats/lipids Structure of fats/lipids Classification of fats Sources of fats Digestion, absorption and metabolism of fats

3. FATS/LIPIDS Substances that are generally insoluble in water but soluble in organic solvents such as ether, acetone and chloroform. Are essential part of the body accounting for a sixth of the body weight. Cells and tissues of the body have fat as an integral component. The vital organs are protected by a sheath of fat and water which holds them in place to prevent injury

4. STRUCTURES OF FATS/LIPIDS Lipids are most often triglycerides which are made up of 3 fatty acids and glycerol. Triglycerides are generated by a condensation reaction and the bond between fatty acid and glycerol is called an ester bond. Fatty acids can be saturated (single bonds between all carbons) or unsaturated (at least one double bond between carbons). This determines whether the compound is a fat or an oil.

5. STRUCTURE OF LIPIDS Composed of elements of carbon, hydrogen and oxygen-similar to carbohydrates but less water. Triglycerides -The most common type of lipids made up of 3 fatty acid chains attached to a glycerol backbone. Fatty acids are chains of carbon atoms(14 and 22) with the end carbon containing a carboxyl group (COOH). The fatty acids in the triglyceride could be the same or have different structures. Glycerol has 3 carbons, with 3 OH molecules attached. The glycerol backbone becomes attached to the 3 fatty acids through condensation reaction because 3 molecules of water are formed

6. STRUCTURE OF LIPIDS

7. STRUCTURE OF LIPIDS The structure of fatty acids influences the structure of the lipid. In the fatty acid chains, the carbon atoms could have a single bond between them making the lipid saturated . This generates fat that are solid at room temperature. If one or more of the bonds between the carbon atoms are double bonds, the lipid is said to be unsaturated . If there is one double bond the triglyceride is said to be monounsaturated . If it has multiple double bonds it is polyunsaturated . Unsaturated fatty acids are usually liquid at room temperature and are called oils.

8. STRUCTURE OF LIPIDS The bond that forms between the fatty acid chain and the glycerol is called an ester bond.

9. CLASSIFICATION OF LIPIDS Lipids can be classified into 3 based on their chemical structure Simple lipids-fats and oils Compound lipids-phospholipids and lipoproteins Derived lipids-fatty acids and sterols

10. SIMPLE LIPIDS Includes fats and oils Every fat molecule has a glycerol at its core and 3 fatty acids attached. Nature-depends on type of fatty acid linked to the glycerol. Saturated fatty acids are solid fats while oils contain unsaturated fatty acids. Edible oils include- soya beans, sunflower, maize, cottonseed, sesame, groundnuts, mustard, olive, coconut, Ghee. Sources of fats-visible fats including oil, vegetable, ghee and butter Invisible fat-oil seed and nut, mutton, eggs, liver and milk

11. COMPOUND LIPIDS Characterized by presence of a non-fat product(other than fatty acid and alcohol) in the molecule according to the nature of that fat. They include the following subtypes Phospholipids Glycolipids Lipoproteins Sulfolipids and amino lipids

12. COMPOUND LIPIDS PHOSPHOLIPIDS Contain phosphorus in the form of phosphoric acid groups which contain substituted fats, composed of glycerol, fatty acids and phosphoric acid bound in ester linked to a nitrogenous base. Lecithin is an important component of all membranes Shingomylins and cerebrosides are found in brain Are important components of active tissues(brain, nervous tissue and the liver) Are emulsifying agents necessary for digestion and absorption of fats

13. COMPOUND LIPIDS PHOSPHOLIPIDS Helps carry lipid particles across the cell membranes in the blood stream. The body makes phospholipids on its own-no need for dietary provision.

14. COMPOUND LIPIDS FUNCTIONS OF PHOSPHOLIPIDS Present in large amounts in the liver, brain and blood. The membrane bounding cells and subcellular organelles are composed of phospholipids Are important components of the lipoprotein coat essential for secretion and transport of plasma proteins. Myelin sheath of nerves is rich with phospholipids. Important in digestion and absorption of neutral lipids. Cholesterol in bile

15. COMPOUND LIPIDS FUNCTIONS OF PHOSPHOLIPIDS CONT. Important in blood clotting and platelet aggregation Provide lung alveoli with surfactant that prevents lung collapse. Important in signal transduction across the cell membrane. Source of polyunsaturated fatty acids SOURCES OF PHOSPHOLIPIDS Found in cells, milk and egg-yolk in the form of lecithin

16. COMPOUND LIPIDS LIPOPROTEINS Lipids combined with proteins in tissues. The protein part of lipoprotein is called apolipoprotein The lipid component of lipoproteins are mostly triglycerides, free and esterified cholesterol and phospholipids. Lipoprotein structure consist of non-polar lipid core surrounded by apoproteins and more polar lipids

17. COMPOUND LIPOPROTEINS CLASSES OF LIPOPROTEINS Chylomicrons-Transport of lipids to adipose tissue for storage and to muscles or heart for energy needs Very low density lipoproteins(VLDL)-Transport of TG synthesised in the liver as VLDL to the peripheral tissues Low density lipoproteins(LDL)-Transport of cholesterol from liver to peripheral tissues High density lipoproteins(HDL)-Protective particles. Transport cholesterol from tissues to the liver for synthesis of bile and steroid hormones. HDLs play a key role in protecting against heart disease.

18. DERIVED LIPIDS Are the hydrolysis products of simple and compound lipids and/or their derivatives that still possess the general characteristics of lipids. They include fatty acids, glycerol, steroids, bile acids and substances associated with lipids in nature such as carotenes, vitamins A,D,K and E.

19. FUNCTIONS OF LIPIDS Source of energy, each gram of fat supplies upto 10 calories. Source of essential fatty acids and fat soluble vitamins(A, D, K and E) Fats are used to synthesis phospholipids found in most cells. Fat stored as adipose tissue act as a cushion for vital organs. Also protects nerve fibers. Helps conserve body heat and regulate body temperature. This is because it is a poor conductor of heat. Increases the feeling satisfaction because of slow digestion. Forms an important component of cell walls.

20. DIGESTION, ABSORPTION AND METABOLISM OF FAT Majority of ingested fats are triglycerols (TGAs) Mouth-enzymes are aqueous and have little effect on lipids In the stomach, fats are churned into droplets called chime. Gastric lipase begins digestion of fats, 10% of TAGs are hydrolyzed in the stomach. Chyme stimulates cholecystokinin to release bile from the gall bladder. Bile is an emulsifier for lipids

21. DIGESTION OF FATS CONT Pancreatic lipase hydrolyzes insoluble triglyceride by binding to bile-salt micelles. TAGs are partially hydrolyzed, 2 of the 3 F.As have ester linkages hydrolyzed and released. A monoacyglyceral remains-glycerol + 1 fatty acid Oil droplets form a spherical micelle shape aided by bile salts during which clumping of fatty acids and monocylglycerols take place

22. DIGESTION OF FATS CONT Fatty acid micelle-hydrophobic fatty acids and monocylglycerols are in the anterior and bile salts in the posterior. Micelles are small enough to penetrate the membrane of intestinal cells. Free fatty acids and monoacylglycerols are reformed into triacyglycerols . TAGs are combined with membrane and water soluble proteins to form chylomicron a lipoprotein. Chylomicrons carry TAGs from the intestinal cell into the blood stream via the lymphatic system

23. DIGESTION OF FATS CONT Triacylglycearols reach the bloodstream and are hydrolyzed down to glycerol and fatty acids. These are absorbed by cells and processed further for energy by forming acetyl CoA.

24. RDA FOR FATS Based on 2 factors-need to meet energy needs and essential fatty acid needs. 12g of fat is needed daily by the body. A higher level of 20g/day may be needed to provide energy density for normal adults. Maximum intake-20g/day for adults and 25g/day for children

25. VITAMINS

26. VITAMINS Organic substances which occur in small amounts in the body and are essential for life and growth. Substance classified as vitamins satisfy the criteria below Must be vital and only needed in very small amounts to perform specific functions Cannot be synthesized in the body and must be supplied in the diet

27. NATURE OF VITAMINS Occur in small amounts in the body. Are necessary for life and growth Chemical structure of each vitamin is specific Do not provide calories, but are essential for metabolic reactions which release energy from carbohydrates, fats and proteins Are essential co-factors in many metabolic reactions Each vitamin has a specific function, one cannot substitute for another

28. CLASSIFICATION OF VITAMINS Classified based on solubility Fat Soluble vitamins Include A,D,E and K Water soluble B group and vitamin C

29. FAT SOLUBLE VITAMINS Can only be absorbed in the presence of fat-presence of some fat in the diet is essential for absorption. Can be stored in the body, high intake is protective during periods of low intake. Requirements are met by intake of the vitamin or by intake of a precursor. Not lost during cooking

30. VITAMIN A Occurs as retinoids (retinal, retinal, retinoic acid) and carotenes( α , β and ϒ ) Chief source in humans is beta-carotene which the body converts to vit A in the intestinal mucosa during absorption. FUNCTONS OF VITAMIN A Function in vision-occurs in the retina and required for dark adaptation. Health of epithelial cells-Deficiency results in suppression of normal secretions and produces keratinized epithelium. Immune response-Functions in T-cell mediated response

31. VITAMIN A FUNCTIONS Haemopoesis -Deficiency associated with iron deficiency anemia Growth- Retonic acid controls growth and development of tissues in the musculoskeletal system Energy balance CNS development Gap junction development

32. VITAMIN A SOURCES Present in animal foods only-Liver, butter, ghee, milk, curds and egg yolk Leafy vegetables-spinach, amaranth, coriander and drumstick leaves . Ripe fruits such as mango, papaya and pumpkins are sources of beta-carotene. RDA Adult-600 mcg of retinal or 2400 mcg of beta-carotene Infants 350 mcg of retinal

33. VITAMIN A EFFEECTS ACROSS THE LIFESPAN Pregnancy Morphological and functional development of the fetus Lactation Mammary gland metabolism Regulates weaning process Infancy and childhood Maintains eye integrity Boosters immune system

34. VITAMIN A EFFECTS ACROSS THE LIFESPAN Adolescence Xeropthalmia prevention Dysplasia and anemia prevention Early adulthood Regulates immunity and vision Obesity control Middle age Influences the risk of hip fractures Beneficial in cases of open angle glaucoma

35. VITAMIN A EFFECTS ACROSS THE LIFESPAN Elderly Regulates fat mass Affects bone mineral density

36. VITAMIN D Isolated in 1930 and named calceferol Called “sunshine vitamin”-the body is able to convert a precursor of 7-dehydrocholesterol to VIT D in the presence of sunlight Can be synthesized in the body by exposure to sunlight for five minutes daily. FUNCTIONS Absorption of calcium and phosphorus Bone mineralization

37. SOURCES OF VITAMIN D Found in small quantities in liver, egg yolk, milk and milk fat Fish liver oils,-halibut, cod, shark and sawfish taken as supplements RDA 5 mcg or 200 IU is recommended for children Recommendation for adults is not known

38. VITAMIN D EFFECTS ACROSS THE LIFESPAN Pregnancy Maintains maternal and fetal immune system Improves bone health Prevents pregnancy induced hypertension Prevents pregnancy induced diabetes Lactation Prevents autism Prevention of rickets

39. VITAMIN D EFFECTS ACROSS THE LIFESPAN Infancy and Childhood Improves immune function Prevents childhood asthma Participates in development of the nervous system Adolescence Bone development Mental health maintenance Boost the immune system

40. VITAMIN D EFFECTS ACROSS THE LIFESPAN Early adulthood Strengthens immune system Lowers risk of multiple sclerosis Lowers risk of type 2 diabetes mellitus Middle age Improves quality of life and physical performance Lowers risk of sarcopenia Elderly Reduces risk of bone fractures and falls

41. VITAMIN E Also called alpha- tocopherol . No proof of vitamin E deficiency in adults has been established Main function – Fat soluble anti-oxidant Sources-Vegetable oils, cereals, leafy vegetables, milk, eggs, muscle meats and fish RDA-0.8mg/g of essential fatty acids

42. VITAMIN E EFFECTS ACROSS THE LIFESPAN Pregnancy Decreases the risk of asthma in the babies Reduces the risk of low birth weight infant Lactation Regulates the developmental process Infancy and childhood Decreases the risk of asthma and ataxia

43. VITAMIN E EFFECTS ACROSS THE LIFESPAN Adolescence Enhances physical activity Enhances academic performance Improves outcomes for patients with non-alcoholic liver disease Early adulthood Improves endothelial cell function Middle age Has anti-aging effects Decrease's the risk of stroke occurrence

44. VITAMIN E EFFECTS ACROSS THE LIFESPAN Middle age Cont ’ Decreases the risk of fractures Elderly Is an immune booster Maintains hemostasis

45. VITAMIN K Phylloquinone is the major form of VIT K found in plants and in food. Function-Blood clotting, essential for formation of thrombin in the liver. Sources-Green leafy vegetables

46. VITAMIN K EFFECTS ACROSS THE LIFESPAN Pregnancy Lowers the risk of coagulopathy Inhibits intrahepatic cholestasis of pregnancy Lactation Aids in coagulation factor formation Infancy and childhood Preventive treatment of bleeding associated with Vitamin K deficiency

47. VITAMIN K EFFECTS ACROSS THE LIFESPAN Adolescence Important in healthy bone development Maintains hemostasis Early Adulthood Suppression diabetes mellitus progression Management of type 2 diabetes mellitus Middle age Lowers risk of heart disease Lowers risk of hip fractures

48. VITAMIN K EFFECTS ACROSS THE LIFESPAN Elderly Has anti-hemophilia effects Protects against osteoporosis

49. WATER SOLUBLE VITAMINS Consist of a large number of substances including ascorbic acid and B-complex vitamins Are absorbed quickly in the body and the excessive amounts not utilized are excreted in the body. Some are partly lost during cooking

50. VITAMIN B-COMPLEX 6 B vitamins have been identified and grouped together. Definite requirements of these vitamins have been established. All are essential for human nutrition. The B vitamins include thiamine, riboflavin, niacin, pyridoxine, folic acid and vitamin B 12

51. THIAMINE Also known as Vitamin B1 FUNCTIONS A co-enzyme for the release of heat from glucose and its storage as fat. Needed to maintain the normal functions of the GI system, nervous system and cardiovascular system through production of energy. Sources-Pulses, nuts, oilseeds and whole grain, rice and fresh peas, leafy vegetables and animal products such as milk, eggs, fish and meat RDA-0.5 mg per 1000 calories for all age groups

52. RIBOFLAVIN-VITAMIN B2 Second vitamin discovered after niacin Function -Co-enzyme in energy production and tissue protein building. Sources -Milk and milk products, liver and kidneys, pulses, green leafy vegetables, eggs and meat. RDA - 0.60mg/100 kcal

53. NIACIN Includes both nicotinic and nicotinamide . The amide is soluble in water and both are heat stable Functions -Acts as an important component of 2 co-enzyme NAD and NADP. This aides in breakdown of glucose to provide energy Sources -Groundnuts, liver, milk, eggs, fruits and vegetables

54. PYRODOXINE Three naturally occurring derivatives of pyridoxine are known as vitamin B6 Function -Co-factor for enzymes connected with metabolism of amino acids. Has a role in formation of antibodies. Sources -Pulses, wheat, meat, vegetables and fruits RDA -0.4 mgs for infants to 2 mgs for adults, 2,5 mgs for lactating and pregnant women Deficiency -Signs include peripheral neuritis, anemia, glossitis and seborrhic dermatitis

55. FOLIC ACID Pteroyl -mono-glutamic acid, first isolated in 1941 Functions -Synthesis of metabolites in the body, synthesis of nucleic acid. Sources -Green leafy vegetables, liver, legumes. Upto 50% can be lost during cooking hence the need for supplementation especially in pregnancy. Body requirements - 100 mcg daily for adults and 25mcgs for infants

56. VITAMIN B12 Also called cyanocobolamine Functions -Promotes normal growth and development, essential component of several enzymes necessary for synthesis of nucleic acid, essential for functioning of bone marrow cells, nervous system and GI tract. Sources -Organ meats, milk, eggs, fish and muscle meat.

57. ASCOBIC ACID (VITAMIN C) Isolated in 1932 Function -Building and maintainace of tissue especially connective tissues, building of strong capillary walls, partner in protein synthesis, building resistance to infection, aides in absorption of iron. Sources -Citrus fruits, leafy vegetables, amaranth, cabbage and drumstick leaves

58. MINERALS

59. INTRODUCTION These are essential nutrients that represent about 5-6% of the body weight. Classified into 2 depending on the percentage of body weight and the amount required in the diet. Major/ macrominerals are present in the body at levels greater than 0.01% and are required in amounts greater than 100 mg/day and have structural and regulatory roles. Macrominerals include calcium, phosphorus, sodium, potassium, magnesium and chloride.

60. INTRODUCTION Trace/micronutrients are present in the body in at levels less than 0.01% and are required in the body in amounts less than 50 mg/day. They are important regulation, metabolism and healthy immune functions. Trace elements include iron, cobalt, chromium, copper, fluoride, iodine, manganese, selenium, zinc and molybdenum

61. FUNCTIONS OF MICRONUTRIENTS Cofactors in metabolism-trace elements are involved in modulating enzyme activity Coenzymes in metabolism-many vitamins or third metabolites are required in complex biochemical reactions. This ensures utilization of major nutrients to provide energy, proteins and nucleic acid Genetic control-zinc is involved in transcription that bind to DNA and regulates transcription receptors for steroid hormones and other factors Are antioxidants-Reduces oxidative stress