Ingestion, Digestion, Absorption, Metabolism, Transport, Excretion Carbohydrates Lipids

1. Ingestion, Digestion, Absorption, Metabolism, Transport, ExcretionCarbohydratesLipids

2. What happens when we eat?-entry to exit • Ingestion (I)-food and drink in mouth • Digestion (D)-breaking to food down to absorbable units • Absorption (A)-absorbable units cross the gi tract to blood or lymph • Transport (T)-movement about the body in blood or lymph to cells for metabolism • Metabolism(M)-all the chemical reactions that occur in the body-more on this later in the course • Excretion (E)-waste leaves body in urine and faeces primarily • Whole idea with IDATME is to get nutrients to where (W) they are needed, when (W) they are needed, in the form (F) they are needed and in the quantity (Q) they are needed-IDATME and WWFQ must be a tightly choreographed operation or body shuts down • Remember IDATME WWFQ

3. IDATME VIDEO • https://www.youtube.com/watch?v=08VyJOEcDos

4. CarbohydratesChapter 2

5. Carbohydrates • More than just “sugar” and “starch” • Provide the majority of calories in almost all human diets • Carbohydrate classifications • Carbohydrates • Class of energy-yielding nutrients that contain only carbon, hydrogen, and oxygen, hence the common abbreviation of CHO • CH2O is the basic formula and hence the name carbohydrate carbo = carbon and hydrate = H2O • Simple carbohydrates contain only one or two saccharide units (monosaccharide and disaccharides). Mono = 1 and di = 2 • Complex carbohydrates contain many saccharide unit molecules (oligosaccharides (3-10 saccharide units and polysaccharides (> 10 saccharide units)).

6. Carbohydrates—(cont.) • Carbohydrate classifications—(cont.) • Monosaccharides-single saccharide units • Simplest of all sugars • Most common • Glucose • Fructose • Galactose

7. Carbohydrates—(cont.)Monosaccharides-building blocks of disaccharides, oligosaccharides and polysaccharides

8. Carbohydrates—(cont.) • Carbohydrate classifications—(cont.) • Monosaccharides—(cont.) • Glucose • Also known as dextrose • Component of all disaccharides • Sugar into which the body converts all other digestible carbohydrates

9. Carbohydrates—(cont.) • Carbohydrate classifications—(cont.) • Monosaccharides—(cont.) • Fructose or “fruit sugar” • Sweetest of all natural sugars • High-fructose corn syrup (HFCS) • Galactose • Does not occur in appreciable amounts in foods • Combines with glucose to form lactose

10. Carbohydrates—(cont.) • Carbohydrate classifications—(cont.) • Disaccharides • Made of two linked monosaccharides • Sucrose, maltose, and lactose are disaccharides. • Sucrose or “table sugar” • Composed of glucose and fructose • Occurs naturally in some fruits and vegetables

11. Carbohydrates—(cont.) • Carbohydrate classifications—(cont.) • Disaccharides—(cont.) • Maltose • Composed of two joined glucose molecules • Not found naturally in foods • Results from breakdown of starch in humans • Lactose or “milk sugar” • Composed of glucose and galactose • Found naturally in milk • Least sweet of all sugars

12. Carbohydrates—(cont.) • Carbohydrate classifications—(cont.) • Disaccharides—(cont.)

13. Carbohydrates—(cont.) • Carbohydrate classifications—(cont.) • Complex carbohydrates • Oligosaccharides • 3-10 saccharide units • Found naturally in foods e.g. beans (e.g. raffinose and stachyose) • Some are tough to digest and are passed to the large intestine where bacteria make gas, short chain fatty acids and lactic acid from them • Are now considered to be dietary fibre

14. Carbohydrates—(cont.) • Carbohydrate classifications—(cont.) • Polysaccharides • Complex carbohydrates • Do not taste sweet • Starch, glycogen, and fibre are types of polysaccharides.

15. Carbohydrates—(cont.) • Carbohydrate classifications—(cont.) • Polysaccharides—(cont.) • Starch • Glucose not used by plants stored as starch • Grains • World’s major food crops • Foundation of all diets • Potatoes, dried peas and beans have starch

16. Carbohydrates—(cont.) • Carbohydrate classifications—(cont.) • Polysaccharides—(cont.) • Glycogen • Animal (including human) version of starch • Liver glycogen releases glucose into the bloodstream to maintain blood sugar between meals. • No dietary source of glycogen

17. Oligosaccharides-part of fibre

18. Carbohydrates—(cont.) • Carbohydrate classifications—(cont.) • Polysaccharides—(cont.) • Fibre • Generally considered a group name for oligosaccharides and polysaccharides that cannot be digested by human enzymes • Commonly referred to as “roughage” • Categorized as water-insoluble or water-soluble • Commonly assumed that fibre does not provide any calories • However, fibre is broken down by bacteria in the colon to form short chain fatty acids (acetic, proprionic and butyric) acids and lactic acid all of which can be used for energy • Gases (H2, CO2, CH4) is also formed by bacteria in the colon

19. Carbohydrates—(cont.) • Sources of carbohydrates • Grains, Vegetables, Fruits, and Dairy are provide the majority of carbohydrates. • Nuts and dried peas and beans • Grains • Synonymous with “carbs” • Classified as “whole” or “refined”

20. Carbohydrates—(cont.) • Sources of carbohydrates—(cont.) • Grains—(cont.) • Whole grains • Consist of the entire kernel of a grain • Can be cracked, ground, or milled into flour • Composed of three parts • The bran • The endosperm • The germ (embryo)

22. Carbohydrates—(cont.) • Sources of carbohydrates—(cont.) • Grains—(cont.) • “Refined” grains • Grains rich in starch but as the result of refining lose fibre, vitamins, trace minerals, fat, and phytochemicals found in whole grains so have to be enriched with e.g. folic acid • Enrichment • “Enriched” versus “fortified” -enriched foods have nutrients added back in after refinement . Fortified foods add more nutrients to the food, rather than replacing the removed nutrients. • Examples include white flour, white bread, white rice, and refined cornmeal.

23. Carbohydrates—(cont.) • Sources of carbohydrates—(cont.) • Vegetables • Starch and some sugars provide the majority of calories in vegetables. • “Starchy” vegetables provides three times more carbohydrate than the same amount of “watery” vegetables.

24. Carbohydrates—(cont.) • Sources of carbohydrates—(cont.) • Fruits • Almost all of the calories in fruit come from sugar (mostly fructose), with small amounts of starch and minute quantities of protein providing negligible calories. • Exceptions to this are avocado, olives, and coconut, which get the majority of their calories from fat. • fibre is located in the skin of fruits.

25. Carbohydrates—(cont.) • Sources of carbohydrates—(cont.) • Dairy • One cup of milk provides 12 g of carbohydrate in the form of lactose. • Cottage cheese, which has about 6 g of carbohydrate per cup • Empty calories • e.g. soft drinks • Carbohydrate content varies

26. Carbohydrates—(cont.) • How the body handles carbohydrates • Digestion • Cooked starch begins to undergo digestion in the mouth by the action of salivary amylase. • Most carbohydrate digestion occurs in the small intestine. • Disaccharidase enzymes split disaccharides into monosaccharides. • Monosaccharides are the only form of carbohydrates the body is able to absorb intact. • Normally, 95% of starch is digested usually within 1 to 4 hours after eating.

27. Carbohydrates—(cont.) • How the body handles carbohydrates—(cont.) • Absorption • Monosaccharides are absorbed through intestinal mucosa cells. • Undigested starch passes with stools. • Fibres may impair the absorption of some minerals—namely, calcium, zinc, and iron—by binding with them in the small intestine.

28. Carbohydrates—(cont.) • How the body handles carbohydrates—(cont.) • Metabolism • Fructose and galactose are converted to glucose in the liver. • Liver releases glucose to maintain blood sugar level. • Rise in blood sugar causes pancreas to release insulin. • Postprandial state • Blood glucose concentration begins to drop. • Pancreas releases glucagon. • Glucagon stimulates liver to release glucose.

29. Carbohydrates—(cont.) • How the body handles carbohydrates—(cont.) • glycaemic response to foods • Increase in blood glucose levels • glycaemic index (GI) • Determined by comparing the impact on blood glucose after 50 g of a food sample is eaten compared to the impact of 50 g of pure glucose or white bread= GI= 100 • May help diabetics and athletes but is controversial and not found on food labels and not all foods have been assigned a GI value so its current utility is limited

30. Carbohydrates—(cont.) • How the body handles carbohydrates—(cont.) • Glycaemic index

31. Carbohydrates—(cont.) • How the body handles carbohydrates—(cont.) • Glycaemic response to foods • Glycaemic index • Whole grain foods have a lower glycaemic index than white bread • potato > yam legumes > root veggies fruits ~ legumes • Fruits about equal to milks in GI (fructose ~ lactose in terms of GI) • Meats- GI = 0 (no carbs in meat)

32. Carbohydrates—(cont.) • How the body handles carbohydrates—(cont.) • Low glycemic index (GI of 55 or less): Most fruits and vegetables, beans, minimally processed grains, pasta, low-fat dairy foods, and nuts. • Moderate glycemic index (GI 56 to 69): White and sweet potatoes, corn, white rice, couscous, breakfast cereals such as Cream of Wheat and Mini Wheats. • High glycemic index (GI of 70 or higher): White bread, rice cakes, most crackers, bagels, cakes, doughnuts, croissants, most packaged breakfast cereals.

33. Carbohydrates—(cont.) • How the body handles carbohydrates—(cont.) • glycaemic response to foods—(cont.) • glycaemic load= GI times the carbohydrate (grams) in food (note grams of carbohydrate means carbohydrate in food not including fibre)

34. Carbohydrates—(cont.) • How the body handles carbohydrates—(cont.) • Glycaemic load • Not reliable for choosing healthy diet

35. Carbohydrates—(cont.) • How the body handles carbohydrates—(cont.) • Glucose metabolism = balance between catabolism (tear down) and anabolism (build up)

36. Carbohydrates—(cont.) • How the body handles carbohydrates—(cont.) -Functions of carbohydrates • Glucose for energy • Primary function of carbohydrates is to provide energy for cells. • Brain is totally dependent on glucose for energy. • Spares protein and prevents ketosis • Protein sparing • Need to consume adequate carbohydrates

37. Carbohydrates—(cont.) • How the body handles carbohydrates—(cont.) • Functions of carbohydrates—(cont.) • Preventing ketosis • Without adequate glucose, fat oxidation prematurely stops at the intermediate step of ketone body formation. • Increased production of ketones causes nausea, fatigue, loss of appetite, and ketoacidosis. • Dehydration and sodium depletion may follow.

38. Carbohydrates—(cont.) • Using glucose to make other compounds • Glycogen • Body’s backup supply of glucose • One-third of the body’s glycogen reserve is in the liver. • Nonessential amino acids • Carbohydrate-containing compounds • Fat

39. Carbohydrates—(cont.) • Dietary reference intakes • Total carbohydrate • The RDA for carbohydrates is set at 130 g for both adults and children. • Acceptable macronutrient distribution range 45-65 % of calories • Fibre • Adequate intake for total fibre is set at 14 g/ 1000 calories. • Sugar • Maximal level of 25% of total calories or less from added sugars is recommended.

40. Carbohydrates—(cont.) However, World Health Organisation indicated on 5 March 2014 that keeping one’s simple sugar (mono and disaccharides) consumption to less than 5 % of daily calories (i.e. less than about 6 teaspoons of sugar) has added health benefits compared to keeping one’s simple sugar (mono and disaccharides) consumption than 10 % of calories (WHO’s previous recommendation). This refers to all simple sugars whether they are added (pop, cakes) or naturally (e.g. honey, fruit) occurring.

41. Carbohydrates in Health Promotion • Concentrate on fibre and whole grains • Most consistent benefit of consuming adequate fibre is to relieve or prevent constipation. • Linked to a decreased risk of heart disease, cancer, diabetes, and obesity • Dietary guidelines recommend that adults and children consume at least one-half of their grain servings from whole grains. • Results in 20% to 30% lower risk of atherosclerotic cardiovascular disease

42. Carbohydrates in Health Promotion—(cont.) • Concentrate on fibre and whole grains—(cont.) • Dietary guidelines—(cont.) • Less likely to develop insulin resistance and metabolic syndrome, common precursors of type 2 diabetes • Associated with improved body weight management • Tips for choosing whole grains • Factors contributing to the low intake of whole grains include consumers’ inability to identify whole grains, a lack of awareness of their health benefits, cost, taste, and unfamiliarity with how to prepare whole grains.

43. Carbohydrates in Health Promotion—(cont.) • How to increase dietary fibre • Replace refined grains with whole grains. • Choose a ready-to-eat cereal with 5 g of fibre or more per serving. • Eat dried peas and beans two to three times per week. • Eat at least five servings of fruits and vegetables daily. • Eat a variety of plant foods daily. • Increase fibre intake gradually to avoid GI intolerance. • Consume adequate fluid.

44. Carbohydrates in Health Promotion—(cont.) • Limit added sugars • Sugar adds flavor and interest. • Limiting intake is prudent-added sugars contribute to obesity • Sugar alternatives • Sugar alcohols • Nonnutritive sweeteners (e.g. sucralose aspartame, saccharin, cyclamate)

45. Carbohydrates in Health Promotion—(cont.) • Limit added sugars—(cont.) • Sugar alternatives—(cont.) • Sugar alcohols • Sorbitol, mannitol, and xylitol • Natural sweeteners derived from monosaccharides • Most are commercially synthesized. • Incompletely absorbed • Side effects • Offer sweetness without promoting cavities

46. Carbohydrates in Health Promotion—(cont.) • Limit added sugars—(cont.) • Sugar alternatives—(cont.) • Nonnutritive sweeteners • Virtually calorie free • Sweeter than sugar • Do not raise blood glucose levels • Risks and benefits of nonnutritive sweeteners • Weight management • Diabetes mellitus • Safety

47. Carbohydrates in Health Promotion—(cont.) • Take steps to avoid dental caries • Choose between-meal snacks that are healthy and teeth-friendly. • Limit between-meal carbohydrate. • Avoid high-sugar items. • Brush promptly after eating. • Chew gum sweetened with sugar alcohols. • Use fluoridated toothpaste.

48. Carbohydrates in Health Promotion—(cont.) • The most common sources of added sugars in the Canadian diet • Soft drinks • Cakes, cookies, and pies • Fruit drinks and punches • Dairy desserts such as ice cream • Candy

49. Carbohydrates in Health Promotion—(cont.) • Sugar: too much of a good thing • Behavioral problems in children-false • Obesity-true • Diabetes mellitus-type 2-true • Atherosclerotic heart disease-true

50. Lipids-Chapter 4 • Low-fat diets do not always mean weight loss. • “Good” (unsaturated) • Eat in moderation-too much causes weight gain • “Bad” (saturated fat and trans fats) • Limited-note however that now saturated fats are considered less problematic than before however recommendation is that dietary saturated fats make up less than 10 % of daily calories remains