Carbohydrates

This Slide share includes Carbohydrate and its Nutrition. It includes introduction, classification, digestion and absorption, sources, RDA and effects of excess and limited use of carbs and fibre and its health effects.

1. Mrs.Nagamani.T Quality Health care College of Nursing Dept.of Community Health Nursing CARBOHYDRATES

2. Introduction: Carbohydrates are * a major source of energy from our diet. * composed of the elements C, H and O. * also called saccharides, which means “sugars .” * are produced by photosynthesis in plants. * such as glucose are synthesized in plants from CO 2 , H 2 O, and energy from the sun. * are oxidized in living cells to produce CO 2 , H 2 O, and energy.

3. Carbohydrates are sugars and provide energy when consumed. Our bodies break down carbohydrates to extract energy. Carbon dioxide and water are released in the process. Glucose is the primary carbohydrate our bodies use to produce energy. Carbohydrates are classified as biomolecules. Simple carbohydrates are referred to as simple sugars and are often sweet to the taste. Consumption of more sugar than is needed for energy results in conversion of these sugars to fat. Complex carbohydrates include starches and the plant and wood fibers known as cellulose .

4. Introduction to Carbohydrates, Continued Carbohydrates are found on the surface of cells where they act as “road signs” allowing molecules to distinguish one cell from another. ABO blood markers found on red blood cells are made up of carbohydrates. They allow us to distinguish our body’s blood type from a foreign blood type. Carbohydrates in our body prevent blood clots. They are also found in our genetic material.

5. Carbohydrates also can combine with lipids to form glycolipids OR With proteins to form glycoproteins .

6. Classification of Carbohydrates Monosaccharides are the simplest carbohydrates. They cannot be broken down to smaller carbohydrates . Disaccharides consist of two monosaccharide units joined together; they can be split into two monosaccharides. Sucrose, table sugar, can be broken down into glucose and fructose . Oligosaccharides contain anywhere from three to nine monosaccharide units. ABO blood groups are oligosaccharides . Polysaccharides are large molecules containing 10 or more monosaccharide units. Carbohydrate units are connected in one continuous chain or the chain can be branched.

7. Monosaccharide One S u g a r Unit I m p o r t a n t S ingle S uga r a r e Glucos e , F r ucto s e , Galactose Glucose (Dextrose): G i v e Energy f o r b o d y Act i v i ty It i s p r i m a r y Fue l of Cell I t u s u a l l y no t f oun d i n D i et ( C o r n S y r up) P r oduc e f r om S t a r c h.

8. Monosaccharide Fructose: F ruit, H o n e y S w eete s t of S i m p l e S ugar Soft drink, Ready to use Cereals, Desserts Galactose: Milk S u g a r

9. Monosaccharides ; Some Important Monosaccharides Glucose is the most abundant monosaccharide found in nature . Glucose is also known as dextrose, blood sugar, and grape sugar. Glucose is broken down in cells to produce energy . Diabetics have difficulty getting glucose in their cells, which is why they must monitor their blood glucose levels regularly. Galactose is found combined with glucose in the disaccharide lactose, which is present in milk and other dairy products. Mannose, a monosaccharide, is found in some fruits and vegetables. Cranberries contain high amounts of mannose, which has been shown to be effective in urinary tract infections.

10. Monosaccharides, Continued Fructose commonly referred to as fruit sugar or levulose. Fructose is combined with glucose to give sucrose, or table sugar. Fructose is the sweetest monosaccharide and is found in fruits, vegetables, and honey. Fructose can be broken down for energy in the body .

11. Benedict’s test is a useful test to determine the presence of an oxidation reaction that occurs with sugars. Benedict’s test can be used in urine dipsticks to determine the level of glucose in urine. Excess glucose in urine suggests high levels of glucose in blood, which is an indicator of diabetes .

12. C h ara c t er i s t ic s o f M o n o s a c cha r i de A r e Si m p l e Single Sugar Wh i c h r equi r e n o Digesti o n Q u i c k l y abs o rbe d f r o m I n testi n e to Bl o o d an d ca r r ied to the Li v er In Li v er C o n v e r ted i n to G l yc o gen a n d stored. 12

13. 37 Disaccharides Disaccharides consist of two monosaccharide units joined together; they can be split into two monosaccharides . Eg ; Maltose Lactose Sucrose

14. Disaccharide s A r e Si m p l e D ou b l e S u gar Wh i c h Link with t w o Single Sugar I m po r tant D i sa c c ha r i d es a r e Su c r o s e , Lacto s e &Mal t o se Su c r o se = Glu c o se + F r u ct o se e . g . Suga r , B r o wn Sugar Sugarcan e , S uga r beet. 14

15. Disaccharide S L actose = Glucose + G ala c tose e . g . Milk S u g ar La c t o se is les s sol u b le Less S w eet t h a n S u crose M a lt o se = Gluc o se + G l u c o se S t a r c h => M a ltos e => G luc o se S u g a r alc o h o l s su c h S o rbitol Used in Can d ies, B e v er a g e s .

16. Maltose Maltose is known as malt sugar. It is formed by the breakdown of starch. Malted barley, a key ingredient in beer, contains high levels of maltose. During germination of barley seeds, the starch goes through hydrolysis to form maltose. This process is halted by drying and roasting barley seeds prior to their germination . Disaccharides, Continued

17. Disaccharides, Continued Lactose Lactose is known as milk sugar. It is found in milk and milk products. An intolerance to lactose can occur in people who inherit or lose the ability to produce the enzyme lactase that hydrolyzes lactose into its monosaccharide units .

18. Disaccharides, Continued Sucrose Sucrose is known as table sugar. It is the most abundant disaccharide found in nature. Sucrose is found in sugar cane and sugar beets .

19. OLIGO SACCHARIDES Oligosaccharides  are a type of carbohydrate formed when three to 10 simple sugars are linked together.  Small amounts occur naturally in many plants. Oligosaccharides  can have many functions including cell recognition and cell binding . For example , glycolipids have an important role in the immune response . Eg ; maltodextrins  or  cellodextrins ,

20. ABO Blood Types ABO blood types refer to carbohydrates on red blood cells. These chemical markers are oligosaccharides that contain either three or four sugar units.

21. Polysaccharides Polysaccharides are large molecules of monosaccharides that are connected to each other through their anomeric carbons. There are two types of polysaccharides: Storage polysaccharides contain only  -glucose units. Three important ones are starch, glycogen, and amylopectin. Structural polysaccharides contain only  -glucose units. Two important ones are cellulose and chitin. Chitin contains a modified  -glucose unit.

22. Polysaccharide s S tarch = ( Gl u c o s e ) n e . g . C e r e al s , L e g u m e s , T u b e r s G l y c o ge n = ( G luc o se) n A n im a l F oo d Sto r e d in L i v e r & Mu s cl e s Fib e r : P l a n t f oo d – V e g et a b l e , F r uits,Gra i ns Not di g es t ed b y Hu m a n e.g. Cellulose, Hemicellulose, Pectins, Gums, Lignin. 22

23. Amylose and amylopectin—starch Starch is a mixture of amylose and amylopectin and is found in plant foods. Amylose makes up 20% of plant starch . Long chains of amylose tend to coil. Amylopectin makes up 80% of plant starch . During fruit ripening, starch undergoes hydrolysis to produce glucose and maltose, which are sweet. When we consume starch, our digestive system breaks it down into glucose units for use by our bodies. Polysaccharides, Continued

24. Polysaccharides, Continued Glycogen Glycogen is a storage polysaccharide found in animals. Glycogen is stored in the liver and muscles. When glucose is needed, glycogen is hydrolyzed in the liver to glucose.

25. Glycogen Glycogen is the polysaccharide that stores glucose in muscle. is similar to amylopectin, but is more highly branched.

26. Polysaccharides, Continued Cellulose Cellulose contains glucose units bonded This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose. The chain of glucose units is straight. This allows chains to align next to each other to form a strong rigid structure.

27. Heparin Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream. It belongs to a group of polysaccharides called glycosaminoglycans .

28. S o u r ce s o f C a r bo h ydra t es S u g a r : H o n e y , F r ui t s, S o f t D r i nk, M i lk , S u ga r , Starch: Ce r e a ls , P asta , F lo u r , B re a d, P ot a t oes, R o o t V eg e . , Pulses Fibe r : Ce r e a l s , B r a n, Outer skin of F r uit s & V e g e ., B r o wn r i c e , O a t m e a ls P ect i n: F r u i t s .

29. S o u r ce s o f C a r bo h yd r a t es Carbohydrates F oo d S o u r ce Glucose F r u i t s , H on e y , C o r n Sy r u p Fructose F r u i t s , H on e y Galactose Milk Maltose B ac k e d Sta r ch Sucrose C ane & B e a t Sugar Lactose Milk Product Starch & Dex t r in G r ai n s , R o o t & T u be r s , Leg u mes Glycogen M e a t Pro du c t , Sea Fo o d Cellulose V ege t a b les, O u t e r co a t of Seed P ectin & Gum Fruits, Plant Secretion, seeds.

30. F u n ct i on o f C a r b o h ydra t es Energy Supply . Bra i n , C e ll Spare Proteins Synthesis of Substances N o n - e ss e n tial A mi n o ac i d s Glycoproteins Glycolipids Promote complete lipid metabolism Provide Bulk Fiber in the Diet.

31. F u n ct i on o f C a r b o h ydra t e s E n ergy S u pp l y f o r b o d y f u n c t ion Essent i a l f o r t h e Ox id a t ion o f F a t s Pr o t e i n s s p a r ing a c t ion Pr o vi d e C a r b o n f o r sy n t h es i s o f N o n - es s e n t ial Amin o a c ids A r e p r ese n t in s o m e t i s s u e C on s t i t u e n t s A d d fl a v ou r t o D i e t N u c le i c a c id o f C onne c t i v e t i s s u e M a t r ix, G a l a c t o s i d es o f Nerve Tissue Ne c e ssa r y f o r p r op er f u n c t io n ing o f C NS A d eq u a t e h e p a t ic G l ycogen S t o r a ge e n h a n ces no r ma l li v er d e t o x if i c a t ion a b il i t y .

32. RDA of Carbohydrates Carbs are a concentrated source of calories, at 4 calories per gram. The Dietary Guidelines recommends that carbohydrates make up 45 to 65 percent of total daily  calories . So , if you get 2,000  calories  a day, between 900 and 1,300  calories  should be from carbohydrates. That translates to between 225 and 325 grams of carbohydrates a day.

33. DIGESTION AND ABSORPTION OF CARBOHYDRATES Digestion : Process of breaking down of food into simpler compounds

34. Mechanical Digestion Chewing, also known as mastication, crumbles the carbohydrate foods into smaller and smaller pieces to form bolus. Chemical Digestion Salivary glands in oral cavity secrets saliva. Saliva contains enzyme salivary amylase/ptyalin. Salivary amylase hydrolyses starch into maltose and dextrin at pH of 6.8 to 7. Only about 5% starch are broken down in mouth.

35. Mechanical Digestion The strong peristaltic contractions of the stomach mix the carbohydrates into the more uniform mixture of chyme. Chemical Digestion The action of ptyalin continues only inside bolus. About 30-40% of dietary starch is digested before bolus is broken down and acidified. The action of ptyalin is blocked by acidic nature of stomach(pH 1.5). Further breakdown of carbohydrates takes place when the chyme is passed down to the small intestine.

36. Mechanical Digestion There is no mechanical digestion in small intestine. Chemical Digestion The pancreas releases pancreatic juice through a duct. Pancreatic juice contains the enzyme, pancreatic amylase. Enzymes are also secreted by the intestinal cells that line the villi.

37. Hydrolyze oligo - and polysaccharides into monosaccharide as follow: o Starch pancreatic amylase Maltose + Isomaltose maltase o Maltose Glucose +Glucose o Isomaltose isomaltase Glucose + Dextrin Dextrin S u crose Lactose dextrinase Glucose sucrase Glucose + Fructose lactase Glucose + Galactose

38. Certain carbohydrate like cellulose are undigested by human due to lack of enzymes like cellulase. But ,it provides fibers for absorption of water into the large intestine ,expand the muscle walls and trigger the muscle contractions for egestion. Cure for constipation.

39. Digested food from alimentary canal to blood stream. Monosaccharide is absorbed in small intestine. Sodium Glucose Transport Protein(SGLT) in membrane helps absorb glucose and galactose. Fructose absorbed is converted to glucose inside cell.

40. DIETARY FIBRE Dietary fiber , also known as roughage or bulk, includes the parts of plant foods body can't digest or absorb . Dietary fiber — found mainly in fruits, vegetables, whole grains and legumes — is probably best known for its ability to prevent or relieve constipation . Fiber is simply a type of  carbohydrate  found naturally in plant-based foods that is not digestible in humans. 

41. Fiber is commonly classified as soluble, which dissolves in water, or insoluble, which doesn't dissolve. Soluble fiber.  This type of fiber dissolves in water to form a gel-like material. It can help lower blood cholesterol and glucose levels. Soluble fiber is found in oats, peas, beans, apples, citrus fruits, carrots, barley and psyllium . Insoluble fiber.  This type of fiber promotes the movement of material through your digestive system and increases stool bulk, so it can be of benefit to those who struggle with constipation or irregular stools. Whole-wheat flour, wheat bran, nuts, beans and vegetables, such as cauliflower, green beans and potatoes, are good sources of insoluble fiber.

42. Action of Fiber in the Body Insoluble Fiber Ac c el e r a t e GI T rans i t I nc r e a se F ec a l W e i ght P r om o t es b o w el movement Sl o w S t ar c h Hydrolysis D el a ys Gl u c o se Absorption. Soluble Fiber Del a ys GI T r a nsit L o w e r s b lo o d Cholesterols Del ays Gluc o se absorption. 44

43. Health benefits of fiber; Lowers cholesterol:  Soluble fiber has been shown to lower cholesterol by binding to bile (composed of cholesterol) and taking it out of the body. This may help reduce the risk of heart disease. Better regulates blood sugar levels:  A high-fiber meal slows down the digestion of food into the intestines, which may help to keep blood sugars from rising rapidly. Weight control:  A high-fiber diet may help keep you fuller longer, which prevents overeating and hunger between meals. May prevent intestinal cancer:  Insoluble fiber increases the bulk and speed of food moving through the intestinal tract, which reduces time for harmful substances to build up. Constipation:  Constipation can often be relieved by increasing the fiber or roughage in your diet. Fiber works to help regulate bowel movements by pulling water into the colon to produce softer, bulkier stools. This action helps to promote better regularity.

44. Effects of excess intake of carbohydrates Excess carbohydrate intake  places a large metabolic load on the body. When the body constantly has high levels of blood sugars to deal with over time, this leads to weight gain, poor metabolic health and an  increased  risk of heart disease . If  habitually overeating carbohydrates, the excess calories could lead to weight gain. This is especially true of sugars and refined carbs, like white flour, since they don't tend to fill up despite their high calorie count.

45. Type 2 Diabetes Consuming too many carbs, especially those with a high glycemic load, can increase the risk of several disorders, including Type 2 diabetes. After consuming a carbohydrate-containing meal the blood sugar increases, pancreas releases insulin, which helps convert glucose into a storage compound in the liver, muscles and other tissues. This eventually lowers the blood sugar. Type 2 diabetes develops when the body stops making insulin or become insensitive to it.

46. Cardiovascular Disease A diet containing too many carbohydrates can raise the blood level of triglycerides, a type of unhealthy fat that travels in the blood. It can also lower the blood levels of high-density lipoprotein, often referred to as good cholesterol.

47. The glycemic index The   glycemic index (GI)  ranks how quickly a food raises blood sugar levels on a scale of 0 to 100. Foods with a high GI cause rapid spikes in blood sugar. Foods with a low GI take longer for the body to digest, leading to more balanced blood sugar levels. Eating lots of foods with a high GI may increase a person’s risk for type 2 diabetes and other health concerns, including heart disease and overweight. A diet with plenty of low GI foods, together with exercise and regular sleep, can help a person maintain health and a  moderate weight .

48. To follow a low GI diet, a person can eat more unrefined foods, such as: oats, barley, or bran whole-grain bread brown rice plenty of fresh fruit and vegetables fresh, whole fruit instead of juice whole-grain pasta salads and raw vegetables

49. Effects of low intake of carbohydrates Complications such as heart arrhythmias, cardiac contractile function impairment, sudden death, osteoporosis, kidney damage, increased cancer risk, impairment of physical activity and lipid abnormalities can all be linked to long-term restriction of  carbohydrates  in the diet.

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