1. Carbohydrates Part One: A. Classification B. Digestion & Absorption of CHO

2. Carbohydrate Is Made by Photosynthesis CHO

3. Carbohydrate Classifications n Simple CHO = “Sugars” –Monosaccharides: single sugar unit –Disaccharides: two sugar units linked together n Complex CHO= Starch, glycogen, fiber –Polysaccharides: many sugar units linked together

4. Simple CHO: Sugars n Monosaccharides – – – n Disaccharides – – – –

6. condensation hydrolysis

7. Simple Sugars, Cont. n What is sugar good for? n When is sugar considered to be “bad?” – – – –

8. n 10% recommendation –(current U.S. 24%) n high sugar diet can  change in fat distribution toward central adiposity n binge trigger in some, inhibitor in others – highly individual

9. Sugar on the Food Label n n n n fructose/levulose n glucose/dextrose n honey/invert sugar n fruit juice concentrate n corn syrup n corn sweetener n molasses n raw sugar n turbinado sugar

10. Sugar Alcohols n E.g. mannitol, sorbitol, xylitol n Considered “sugar free” sweeteners, but still almost the same kcals as sugar n Sugar free candy -- diarrhea if eaten in excess

11. A word about lactose: milk sugar and lactose intolerance n Enzyme lactase splits lactose into glu-gal in the small intestine n Lactase deficiency causes trouble digesting milk products – – –

12. n Different from milk allergy, immune rx to casein n

13. Carbohydrate Classifications n Simple CHO = “Sugars” –Monosaccharides: single sugar unit –Disaccharides: two sugar units linked together n Complex CHO= Starch, glycogen, fiber –Polysaccharides: many sugar units linked together

14. Complex CHO: Polysaccharides: Several to Hundreds of ____________ Units Linked Together n Starch – n Glycogen – n Fiber –

16. Starch n Long straight or branched chains of hundreds of __________________ units n Sources: –Richest source: –Legumes –Tubers

17. n When eaten, ALL starches are broken down enzymatically to ______________ –(blue dots!) – n One to 4 hours after a meal, all starch  __________________

19. Glycogen n Storage form of CHO in animals. Not found in diet. n More complex and more highly branched than starch – n Limited capacity for storage –

20. n Muscle Glycogen – n Liver Glycogen –

21. Fiber n n Typical U.S. diet: n Most fibers are polysaccharides but –

22. n Most common fibers: cellulose, hemicellulose, and pectin. Also gums, mucilages, and lignins n Sources:

24. Whole Vs. Refined Grains n Whole grains n Label: n n

25. n Refined grains n n Label: n Sources: n

26. “Enriched” n When bran and germ are removed, several vitamins/minerals also n “enriched,” n Shoot for at least half of your grains to be from whole grain sources

28. Soluble vs. Insoluble fiber n Soluble fiber –foods: barley, fruits (apples), legumes, oats, oat bran, rye, seeds, vegetables, nuts n Health benefits: – –lowers serum cholesterol –stool bulk/softening

31. n Insoluble fiber –Foods: brown rice/whole grains/wheat bran, fruits, legumes, seeds, veggies n Health benefits: – –Speeds transit through intestines –delayed starch hydrolysis: slowed glu absorption

33. n If you have a low-fiber diet, add fiber gradually! n n What about fiber supplements? –

34. Carbohydrates n Digestion and absorption of CHO

35. Dietary CHO = starch, sugar, and fiber

36. D&A of CHO n Mouth – – starch Salivary amylase dextrins & maltose glu-glu-glu- glu-glu-glu- glu-glu-glu x100 glu-glu-glu- glu-glu-glu glu-glu

37. n Stomach – – –Mechanical digestion continues in stomach, but –

38. n Small Intestine Starch and dextrins Pancreatic amylase maltose glu-glu-glu- glu-glu-glu glu-glu

39. n Last phase: The brushborder cells of the small intestine. n Enzymes in these cells break down ___________________ to _____________________. maltose lactose sucrose (maltase) (lactase) (sucrase) glu & ________

40. n Monosaccharides are ABSORBED – – –In liver, fru and gal are converted to glu –____________ then regulates the release of glu back into the bloodstream for transport to tissues.

42. Large Intestine (colon) n n n Fiber  –(absorbed & used for E, 0-2kcals/g of fiber) –(Cellulose and lignin completely pass through in feces)

43. So now we have glucose in the liver and the bloodstream. If glu is to fuel the tissues, how is it done? n “Glucose-dependent tissues” rely on glucose for fuel (not fat) –Brain, nervous system, retina, etc. n *** –

44. n Average person enough CHO stored to last ________________ hours n Since we can’t store much, need to rely on dietary CHO. –